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1894 lines
46 KiB
1894 lines
46 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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#include <crypto/hash.h> |
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#include <linux/export.h> |
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#include <linux/bvec.h> |
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#include <linux/fault-inject-usercopy.h> |
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#include <linux/uio.h> |
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#include <linux/pagemap.h> |
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#include <linux/highmem.h> |
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#include <linux/slab.h> |
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#include <linux/vmalloc.h> |
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#include <linux/splice.h> |
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#include <linux/compat.h> |
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#include <net/checksum.h> |
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#include <linux/scatterlist.h> |
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#include <linux/instrumented.h> |
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|
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#define PIPE_PARANOIA /* for now */ |
|
|
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/* covers ubuf and kbuf alike */ |
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#define iterate_buf(i, n, base, len, off, __p, STEP) { \ |
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size_t __maybe_unused off = 0; \ |
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len = n; \ |
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base = __p + i->iov_offset; \ |
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len -= (STEP); \ |
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i->iov_offset += len; \ |
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n = len; \ |
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} |
|
|
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/* covers iovec and kvec alike */ |
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#define iterate_iovec(i, n, base, len, off, __p, STEP) { \ |
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size_t off = 0; \ |
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size_t skip = i->iov_offset; \ |
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do { \ |
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len = min(n, __p->iov_len - skip); \ |
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if (likely(len)) { \ |
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base = __p->iov_base + skip; \ |
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len -= (STEP); \ |
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off += len; \ |
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skip += len; \ |
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n -= len; \ |
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if (skip < __p->iov_len) \ |
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break; \ |
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} \ |
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__p++; \ |
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skip = 0; \ |
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} while (n); \ |
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i->iov_offset = skip; \ |
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n = off; \ |
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} |
|
|
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#define iterate_bvec(i, n, base, len, off, p, STEP) { \ |
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size_t off = 0; \ |
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unsigned skip = i->iov_offset; \ |
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while (n) { \ |
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unsigned offset = p->bv_offset + skip; \ |
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unsigned left; \ |
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void *kaddr = kmap_local_page(p->bv_page + \ |
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offset / PAGE_SIZE); \ |
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base = kaddr + offset % PAGE_SIZE; \ |
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len = min(min(n, (size_t)(p->bv_len - skip)), \ |
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(size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \ |
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left = (STEP); \ |
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kunmap_local(kaddr); \ |
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len -= left; \ |
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off += len; \ |
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skip += len; \ |
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if (skip == p->bv_len) { \ |
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skip = 0; \ |
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p++; \ |
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} \ |
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n -= len; \ |
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if (left) \ |
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break; \ |
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} \ |
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i->iov_offset = skip; \ |
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n = off; \ |
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} |
|
|
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#define iterate_xarray(i, n, base, len, __off, STEP) { \ |
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__label__ __out; \ |
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size_t __off = 0; \ |
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struct folio *folio; \ |
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loff_t start = i->xarray_start + i->iov_offset; \ |
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pgoff_t index = start / PAGE_SIZE; \ |
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XA_STATE(xas, i->xarray, index); \ |
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\ |
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len = PAGE_SIZE - offset_in_page(start); \ |
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rcu_read_lock(); \ |
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xas_for_each(&xas, folio, ULONG_MAX) { \ |
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unsigned left; \ |
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size_t offset; \ |
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if (xas_retry(&xas, folio)) \ |
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continue; \ |
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if (WARN_ON(xa_is_value(folio))) \ |
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break; \ |
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if (WARN_ON(folio_test_hugetlb(folio))) \ |
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break; \ |
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offset = offset_in_folio(folio, start + __off); \ |
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while (offset < folio_size(folio)) { \ |
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base = kmap_local_folio(folio, offset); \ |
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len = min(n, len); \ |
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left = (STEP); \ |
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kunmap_local(base); \ |
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len -= left; \ |
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__off += len; \ |
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n -= len; \ |
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if (left || n == 0) \ |
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goto __out; \ |
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offset += len; \ |
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len = PAGE_SIZE; \ |
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} \ |
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} \ |
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__out: \ |
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rcu_read_unlock(); \ |
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i->iov_offset += __off; \ |
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n = __off; \ |
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} |
|
|
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#define __iterate_and_advance(i, n, base, len, off, I, K) { \ |
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if (unlikely(i->count < n)) \ |
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n = i->count; \ |
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if (likely(n)) { \ |
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if (likely(iter_is_ubuf(i))) { \ |
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void __user *base; \ |
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size_t len; \ |
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iterate_buf(i, n, base, len, off, \ |
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i->ubuf, (I)) \ |
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} else if (likely(iter_is_iovec(i))) { \ |
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const struct iovec *iov = i->iov; \ |
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void __user *base; \ |
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size_t len; \ |
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iterate_iovec(i, n, base, len, off, \ |
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iov, (I)) \ |
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i->nr_segs -= iov - i->iov; \ |
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i->iov = iov; \ |
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} else if (iov_iter_is_bvec(i)) { \ |
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const struct bio_vec *bvec = i->bvec; \ |
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void *base; \ |
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size_t len; \ |
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iterate_bvec(i, n, base, len, off, \ |
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bvec, (K)) \ |
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i->nr_segs -= bvec - i->bvec; \ |
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i->bvec = bvec; \ |
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} else if (iov_iter_is_kvec(i)) { \ |
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const struct kvec *kvec = i->kvec; \ |
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void *base; \ |
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size_t len; \ |
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iterate_iovec(i, n, base, len, off, \ |
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kvec, (K)) \ |
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i->nr_segs -= kvec - i->kvec; \ |
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i->kvec = kvec; \ |
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} else if (iov_iter_is_xarray(i)) { \ |
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void *base; \ |
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size_t len; \ |
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iterate_xarray(i, n, base, len, off, \ |
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(K)) \ |
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} \ |
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i->count -= n; \ |
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} \ |
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} |
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#define iterate_and_advance(i, n, base, len, off, I, K) \ |
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__iterate_and_advance(i, n, base, len, off, I, ((void)(K),0)) |
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|
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static int copyout(void __user *to, const void *from, size_t n) |
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{ |
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if (should_fail_usercopy()) |
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return n; |
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if (access_ok(to, n)) { |
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instrument_copy_to_user(to, from, n); |
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n = raw_copy_to_user(to, from, n); |
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} |
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return n; |
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} |
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|
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static int copyin(void *to, const void __user *from, size_t n) |
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{ |
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size_t res = n; |
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|
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if (should_fail_usercopy()) |
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return n; |
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if (access_ok(from, n)) { |
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instrument_copy_from_user_before(to, from, n); |
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res = raw_copy_from_user(to, from, n); |
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instrument_copy_from_user_after(to, from, n, res); |
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} |
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return res; |
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} |
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|
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static inline struct pipe_buffer *pipe_buf(const struct pipe_inode_info *pipe, |
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unsigned int slot) |
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{ |
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return &pipe->bufs[slot & (pipe->ring_size - 1)]; |
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} |
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|
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#ifdef PIPE_PARANOIA |
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static bool sanity(const struct iov_iter *i) |
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{ |
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struct pipe_inode_info *pipe = i->pipe; |
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unsigned int p_head = pipe->head; |
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unsigned int p_tail = pipe->tail; |
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unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); |
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unsigned int i_head = i->head; |
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unsigned int idx; |
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|
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if (i->last_offset) { |
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struct pipe_buffer *p; |
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if (unlikely(p_occupancy == 0)) |
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goto Bad; // pipe must be non-empty |
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if (unlikely(i_head != p_head - 1)) |
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goto Bad; // must be at the last buffer... |
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|
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p = pipe_buf(pipe, i_head); |
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if (unlikely(p->offset + p->len != abs(i->last_offset))) |
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goto Bad; // ... at the end of segment |
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} else { |
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if (i_head != p_head) |
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goto Bad; // must be right after the last buffer |
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} |
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return true; |
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Bad: |
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printk(KERN_ERR "idx = %d, offset = %d\n", i_head, i->last_offset); |
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printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", |
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p_head, p_tail, pipe->ring_size); |
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for (idx = 0; idx < pipe->ring_size; idx++) |
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printk(KERN_ERR "[%p %p %d %d]\n", |
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pipe->bufs[idx].ops, |
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pipe->bufs[idx].page, |
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pipe->bufs[idx].offset, |
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pipe->bufs[idx].len); |
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WARN_ON(1); |
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return false; |
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} |
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#else |
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#define sanity(i) true |
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#endif |
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|
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static struct page *push_anon(struct pipe_inode_info *pipe, unsigned size) |
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{ |
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struct page *page = alloc_page(GFP_USER); |
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if (page) { |
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struct pipe_buffer *buf = pipe_buf(pipe, pipe->head++); |
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*buf = (struct pipe_buffer) { |
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.ops = &default_pipe_buf_ops, |
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.page = page, |
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.offset = 0, |
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.len = size |
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}; |
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} |
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return page; |
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} |
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|
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static void push_page(struct pipe_inode_info *pipe, struct page *page, |
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unsigned int offset, unsigned int size) |
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{ |
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struct pipe_buffer *buf = pipe_buf(pipe, pipe->head++); |
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*buf = (struct pipe_buffer) { |
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.ops = &page_cache_pipe_buf_ops, |
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.page = page, |
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.offset = offset, |
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.len = size |
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}; |
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get_page(page); |
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} |
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|
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static inline int last_offset(const struct pipe_buffer *buf) |
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{ |
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if (buf->ops == &default_pipe_buf_ops) |
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return buf->len; // buf->offset is 0 for those |
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else |
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return -(buf->offset + buf->len); |
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} |
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|
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static struct page *append_pipe(struct iov_iter *i, size_t size, |
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unsigned int *off) |
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{ |
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struct pipe_inode_info *pipe = i->pipe; |
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int offset = i->last_offset; |
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struct pipe_buffer *buf; |
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struct page *page; |
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|
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if (offset > 0 && offset < PAGE_SIZE) { |
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// some space in the last buffer; add to it |
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buf = pipe_buf(pipe, pipe->head - 1); |
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size = min_t(size_t, size, PAGE_SIZE - offset); |
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buf->len += size; |
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i->last_offset += size; |
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i->count -= size; |
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*off = offset; |
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return buf->page; |
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} |
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// OK, we need a new buffer |
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*off = 0; |
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size = min_t(size_t, size, PAGE_SIZE); |
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if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
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return NULL; |
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page = push_anon(pipe, size); |
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if (!page) |
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return NULL; |
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i->head = pipe->head - 1; |
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i->last_offset = size; |
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i->count -= size; |
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return page; |
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} |
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|
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static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
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struct iov_iter *i) |
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{ |
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struct pipe_inode_info *pipe = i->pipe; |
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unsigned int head = pipe->head; |
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|
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if (unlikely(bytes > i->count)) |
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bytes = i->count; |
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|
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if (unlikely(!bytes)) |
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return 0; |
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|
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if (!sanity(i)) |
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return 0; |
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|
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if (offset && i->last_offset == -offset) { // could we merge it? |
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struct pipe_buffer *buf = pipe_buf(pipe, head - 1); |
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if (buf->page == page) { |
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buf->len += bytes; |
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i->last_offset -= bytes; |
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i->count -= bytes; |
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return bytes; |
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} |
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} |
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if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
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return 0; |
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|
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push_page(pipe, page, offset, bytes); |
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i->last_offset = -(offset + bytes); |
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i->head = head; |
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i->count -= bytes; |
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return bytes; |
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} |
|
|
|
/* |
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* fault_in_iov_iter_readable - fault in iov iterator for reading |
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* @i: iterator |
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* @size: maximum length |
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* |
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* Fault in one or more iovecs of the given iov_iter, to a maximum length of |
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* @size. For each iovec, fault in each page that constitutes the iovec. |
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* |
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* Returns the number of bytes not faulted in (like copy_to_user() and |
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* copy_from_user()). |
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* |
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* Always returns 0 for non-userspace iterators. |
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*/ |
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size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size) |
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{ |
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if (iter_is_ubuf(i)) { |
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size_t n = min(size, iov_iter_count(i)); |
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n -= fault_in_readable(i->ubuf + i->iov_offset, n); |
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return size - n; |
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} else if (iter_is_iovec(i)) { |
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size_t count = min(size, iov_iter_count(i)); |
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const struct iovec *p; |
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size_t skip; |
|
|
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size -= count; |
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for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) { |
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size_t len = min(count, p->iov_len - skip); |
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size_t ret; |
|
|
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if (unlikely(!len)) |
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continue; |
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ret = fault_in_readable(p->iov_base + skip, len); |
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count -= len - ret; |
|
if (ret) |
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break; |
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} |
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return count + size; |
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} |
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return 0; |
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} |
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EXPORT_SYMBOL(fault_in_iov_iter_readable); |
|
|
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/* |
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* fault_in_iov_iter_writeable - fault in iov iterator for writing |
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* @i: iterator |
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* @size: maximum length |
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* |
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* Faults in the iterator using get_user_pages(), i.e., without triggering |
|
* hardware page faults. This is primarily useful when we already know that |
|
* some or all of the pages in @i aren't in memory. |
|
* |
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* Returns the number of bytes not faulted in, like copy_to_user() and |
|
* copy_from_user(). |
|
* |
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* Always returns 0 for non-user-space iterators. |
|
*/ |
|
size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t size) |
|
{ |
|
if (iter_is_ubuf(i)) { |
|
size_t n = min(size, iov_iter_count(i)); |
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n -= fault_in_safe_writeable(i->ubuf + i->iov_offset, n); |
|
return size - n; |
|
} else if (iter_is_iovec(i)) { |
|
size_t count = min(size, iov_iter_count(i)); |
|
const struct iovec *p; |
|
size_t skip; |
|
|
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size -= count; |
|
for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) { |
|
size_t len = min(count, p->iov_len - skip); |
|
size_t ret; |
|
|
|
if (unlikely(!len)) |
|
continue; |
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ret = fault_in_safe_writeable(p->iov_base + skip, len); |
|
count -= len - ret; |
|
if (ret) |
|
break; |
|
} |
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return count + size; |
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} |
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return 0; |
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} |
|
EXPORT_SYMBOL(fault_in_iov_iter_writeable); |
|
|
|
void iov_iter_init(struct iov_iter *i, unsigned int direction, |
|
const struct iovec *iov, unsigned long nr_segs, |
|
size_t count) |
|
{ |
|
WARN_ON(direction & ~(READ | WRITE)); |
|
*i = (struct iov_iter) { |
|
.iter_type = ITER_IOVEC, |
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.nofault = false, |
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.user_backed = true, |
|
.data_source = direction, |
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.iov = iov, |
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.nr_segs = nr_segs, |
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.iov_offset = 0, |
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.count = count |
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}; |
|
} |
|
EXPORT_SYMBOL(iov_iter_init); |
|
|
|
// returns the offset in partial buffer (if any) |
|
static inline unsigned int pipe_npages(const struct iov_iter *i, int *npages) |
|
{ |
|
struct pipe_inode_info *pipe = i->pipe; |
|
int used = pipe->head - pipe->tail; |
|
int off = i->last_offset; |
|
|
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*npages = max((int)pipe->max_usage - used, 0); |
|
|
|
if (off > 0 && off < PAGE_SIZE) { // anon and not full |
|
(*npages)++; |
|
return off; |
|
} |
|
return 0; |
|
} |
|
|
|
static size_t copy_pipe_to_iter(const void *addr, size_t bytes, |
|
struct iov_iter *i) |
|
{ |
|
unsigned int off, chunk; |
|
|
|
if (unlikely(bytes > i->count)) |
|
bytes = i->count; |
|
if (unlikely(!bytes)) |
|
return 0; |
|
|
|
if (!sanity(i)) |
|
return 0; |
|
|
|
for (size_t n = bytes; n; n -= chunk) { |
|
struct page *page = append_pipe(i, n, &off); |
|
chunk = min_t(size_t, n, PAGE_SIZE - off); |
|
if (!page) |
|
return bytes - n; |
|
memcpy_to_page(page, off, addr, chunk); |
|
addr += chunk; |
|
} |
|
return bytes; |
|
} |
|
|
|
static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
|
__wsum sum, size_t off) |
|
{ |
|
__wsum next = csum_partial_copy_nocheck(from, to, len); |
|
return csum_block_add(sum, next, off); |
|
} |
|
|
|
static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
|
struct iov_iter *i, __wsum *sump) |
|
{ |
|
__wsum sum = *sump; |
|
size_t off = 0; |
|
unsigned int chunk, r; |
|
|
|
if (unlikely(bytes > i->count)) |
|
bytes = i->count; |
|
if (unlikely(!bytes)) |
|
return 0; |
|
|
|
if (!sanity(i)) |
|
return 0; |
|
|
|
while (bytes) { |
|
struct page *page = append_pipe(i, bytes, &r); |
|
char *p; |
|
|
|
if (!page) |
|
break; |
|
chunk = min_t(size_t, bytes, PAGE_SIZE - r); |
|
p = kmap_local_page(page); |
|
sum = csum_and_memcpy(p + r, addr + off, chunk, sum, off); |
|
kunmap_local(p); |
|
off += chunk; |
|
bytes -= chunk; |
|
} |
|
*sump = sum; |
|
return off; |
|
} |
|
|
|
size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
|
{ |
|
if (unlikely(iov_iter_is_pipe(i))) |
|
return copy_pipe_to_iter(addr, bytes, i); |
|
if (user_backed_iter(i)) |
|
might_fault(); |
|
iterate_and_advance(i, bytes, base, len, off, |
|
copyout(base, addr + off, len), |
|
memcpy(base, addr + off, len) |
|
) |
|
|
|
return bytes; |
|
} |
|
EXPORT_SYMBOL(_copy_to_iter); |
|
|
|
#ifdef CONFIG_ARCH_HAS_COPY_MC |
|
static int copyout_mc(void __user *to, const void *from, size_t n) |
|
{ |
|
if (access_ok(to, n)) { |
|
instrument_copy_to_user(to, from, n); |
|
n = copy_mc_to_user((__force void *) to, from, n); |
|
} |
|
return n; |
|
} |
|
|
|
static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
|
struct iov_iter *i) |
|
{ |
|
size_t xfer = 0; |
|
unsigned int off, chunk; |
|
|
|
if (unlikely(bytes > i->count)) |
|
bytes = i->count; |
|
if (unlikely(!bytes)) |
|
return 0; |
|
|
|
if (!sanity(i)) |
|
return 0; |
|
|
|
while (bytes) { |
|
struct page *page = append_pipe(i, bytes, &off); |
|
unsigned long rem; |
|
char *p; |
|
|
|
if (!page) |
|
break; |
|
chunk = min_t(size_t, bytes, PAGE_SIZE - off); |
|
p = kmap_local_page(page); |
|
rem = copy_mc_to_kernel(p + off, addr + xfer, chunk); |
|
chunk -= rem; |
|
kunmap_local(p); |
|
xfer += chunk; |
|
bytes -= chunk; |
|
if (rem) { |
|
iov_iter_revert(i, rem); |
|
break; |
|
} |
|
} |
|
return xfer; |
|
} |
|
|
|
/** |
|
* _copy_mc_to_iter - copy to iter with source memory error exception handling |
|
* @addr: source kernel address |
|
* @bytes: total transfer length |
|
* @i: destination iterator |
|
* |
|
* The pmem driver deploys this for the dax operation |
|
* (dax_copy_to_iter()) for dax reads (bypass page-cache and the |
|
* block-layer). Upon #MC read(2) aborts and returns EIO or the bytes |
|
* successfully copied. |
|
* |
|
* The main differences between this and typical _copy_to_iter(). |
|
* |
|
* * Typical tail/residue handling after a fault retries the copy |
|
* byte-by-byte until the fault happens again. Re-triggering machine |
|
* checks is potentially fatal so the implementation uses source |
|
* alignment and poison alignment assumptions to avoid re-triggering |
|
* hardware exceptions. |
|
* |
|
* * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. |
|
* Compare to copy_to_iter() where only ITER_IOVEC attempts might return |
|
* a short copy. |
|
* |
|
* Return: number of bytes copied (may be %0) |
|
*/ |
|
size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
|
{ |
|
if (unlikely(iov_iter_is_pipe(i))) |
|
return copy_mc_pipe_to_iter(addr, bytes, i); |
|
if (user_backed_iter(i)) |
|
might_fault(); |
|
__iterate_and_advance(i, bytes, base, len, off, |
|
copyout_mc(base, addr + off, len), |
|
copy_mc_to_kernel(base, addr + off, len) |
|
) |
|
|
|
return bytes; |
|
} |
|
EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
|
#endif /* CONFIG_ARCH_HAS_COPY_MC */ |
|
|
|
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
|
{ |
|
if (unlikely(iov_iter_is_pipe(i))) { |
|
WARN_ON(1); |
|
return 0; |
|
} |
|
if (user_backed_iter(i)) |
|
might_fault(); |
|
iterate_and_advance(i, bytes, base, len, off, |
|
copyin(addr + off, base, len), |
|
memcpy(addr + off, base, len) |
|
) |
|
|
|
return bytes; |
|
} |
|
EXPORT_SYMBOL(_copy_from_iter); |
|
|
|
size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
|
{ |
|
if (unlikely(iov_iter_is_pipe(i))) { |
|
WARN_ON(1); |
|
return 0; |
|
} |
|
iterate_and_advance(i, bytes, base, len, off, |
|
__copy_from_user_inatomic_nocache(addr + off, base, len), |
|
memcpy(addr + off, base, len) |
|
) |
|
|
|
return bytes; |
|
} |
|
EXPORT_SYMBOL(_copy_from_iter_nocache); |
|
|
|
#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
|
/** |
|
* _copy_from_iter_flushcache - write destination through cpu cache |
|
* @addr: destination kernel address |
|
* @bytes: total transfer length |
|
* @i: source iterator |
|
* |
|
* The pmem driver arranges for filesystem-dax to use this facility via |
|
* dax_copy_from_iter() for ensuring that writes to persistent memory |
|
* are flushed through the CPU cache. It is differentiated from |
|
* _copy_from_iter_nocache() in that guarantees all data is flushed for |
|
* all iterator types. The _copy_from_iter_nocache() only attempts to |
|
* bypass the cache for the ITER_IOVEC case, and on some archs may use |
|
* instructions that strand dirty-data in the cache. |
|
* |
|
* Return: number of bytes copied (may be %0) |
|
*/ |
|
size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
|
{ |
|
if (unlikely(iov_iter_is_pipe(i))) { |
|
WARN_ON(1); |
|
return 0; |
|
} |
|
iterate_and_advance(i, bytes, base, len, off, |
|
__copy_from_user_flushcache(addr + off, base, len), |
|
memcpy_flushcache(addr + off, base, len) |
|
) |
|
|
|
return bytes; |
|
} |
|
EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
|
#endif |
|
|
|
static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
|
{ |
|
struct page *head; |
|
size_t v = n + offset; |
|
|
|
/* |
|
* The general case needs to access the page order in order |
|
* to compute the page size. |
|
* However, we mostly deal with order-0 pages and thus can |
|
* avoid a possible cache line miss for requests that fit all |
|
* page orders. |
|
*/ |
|
if (n <= v && v <= PAGE_SIZE) |
|
return true; |
|
|
|
head = compound_head(page); |
|
v += (page - head) << PAGE_SHIFT; |
|
|
|
if (likely(n <= v && v <= (page_size(head)))) |
|
return true; |
|
WARN_ON(1); |
|
return false; |
|
} |
|
|
|
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
|
struct iov_iter *i) |
|
{ |
|
size_t res = 0; |
|
if (unlikely(!page_copy_sane(page, offset, bytes))) |
|
return 0; |
|
if (unlikely(iov_iter_is_pipe(i))) |
|
return copy_page_to_iter_pipe(page, offset, bytes, i); |
|
page += offset / PAGE_SIZE; // first subpage |
|
offset %= PAGE_SIZE; |
|
while (1) { |
|
void *kaddr = kmap_local_page(page); |
|
size_t n = min(bytes, (size_t)PAGE_SIZE - offset); |
|
n = _copy_to_iter(kaddr + offset, n, i); |
|
kunmap_local(kaddr); |
|
res += n; |
|
bytes -= n; |
|
if (!bytes || !n) |
|
break; |
|
offset += n; |
|
if (offset == PAGE_SIZE) { |
|
page++; |
|
offset = 0; |
|
} |
|
} |
|
return res; |
|
} |
|
EXPORT_SYMBOL(copy_page_to_iter); |
|
|
|
size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
|
struct iov_iter *i) |
|
{ |
|
size_t res = 0; |
|
if (!page_copy_sane(page, offset, bytes)) |
|
return 0; |
|
page += offset / PAGE_SIZE; // first subpage |
|
offset %= PAGE_SIZE; |
|
while (1) { |
|
void *kaddr = kmap_local_page(page); |
|
size_t n = min(bytes, (size_t)PAGE_SIZE - offset); |
|
n = _copy_from_iter(kaddr + offset, n, i); |
|
kunmap_local(kaddr); |
|
res += n; |
|
bytes -= n; |
|
if (!bytes || !n) |
|
break; |
|
offset += n; |
|
if (offset == PAGE_SIZE) { |
|
page++; |
|
offset = 0; |
|
} |
|
} |
|
return res; |
|
} |
|
EXPORT_SYMBOL(copy_page_from_iter); |
|
|
|
static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
|
{ |
|
unsigned int chunk, off; |
|
|
|
if (unlikely(bytes > i->count)) |
|
bytes = i->count; |
|
if (unlikely(!bytes)) |
|
return 0; |
|
|
|
if (!sanity(i)) |
|
return 0; |
|
|
|
for (size_t n = bytes; n; n -= chunk) { |
|
struct page *page = append_pipe(i, n, &off); |
|
char *p; |
|
|
|
if (!page) |
|
return bytes - n; |
|
chunk = min_t(size_t, n, PAGE_SIZE - off); |
|
p = kmap_local_page(page); |
|
memset(p + off, 0, chunk); |
|
kunmap_local(p); |
|
} |
|
return bytes; |
|
} |
|
|
|
size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
|
{ |
|
if (unlikely(iov_iter_is_pipe(i))) |
|
return pipe_zero(bytes, i); |
|
iterate_and_advance(i, bytes, base, len, count, |
|
clear_user(base, len), |
|
memset(base, 0, len) |
|
) |
|
|
|
return bytes; |
|
} |
|
EXPORT_SYMBOL(iov_iter_zero); |
|
|
|
size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, |
|
struct iov_iter *i) |
|
{ |
|
char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
|
if (unlikely(!page_copy_sane(page, offset, bytes))) { |
|
kunmap_atomic(kaddr); |
|
return 0; |
|
} |
|
if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
|
kunmap_atomic(kaddr); |
|
WARN_ON(1); |
|
return 0; |
|
} |
|
iterate_and_advance(i, bytes, base, len, off, |
|
copyin(p + off, base, len), |
|
memcpy(p + off, base, len) |
|
) |
|
kunmap_atomic(kaddr); |
|
return bytes; |
|
} |
|
EXPORT_SYMBOL(copy_page_from_iter_atomic); |
|
|
|
static void pipe_advance(struct iov_iter *i, size_t size) |
|
{ |
|
struct pipe_inode_info *pipe = i->pipe; |
|
int off = i->last_offset; |
|
|
|
if (!off && !size) { |
|
pipe_discard_from(pipe, i->start_head); // discard everything |
|
return; |
|
} |
|
i->count -= size; |
|
while (1) { |
|
struct pipe_buffer *buf = pipe_buf(pipe, i->head); |
|
if (off) /* make it relative to the beginning of buffer */ |
|
size += abs(off) - buf->offset; |
|
if (size <= buf->len) { |
|
buf->len = size; |
|
i->last_offset = last_offset(buf); |
|
break; |
|
} |
|
size -= buf->len; |
|
i->head++; |
|
off = 0; |
|
} |
|
pipe_discard_from(pipe, i->head + 1); // discard everything past this one |
|
} |
|
|
|
static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
|
{ |
|
const struct bio_vec *bvec, *end; |
|
|
|
if (!i->count) |
|
return; |
|
i->count -= size; |
|
|
|
size += i->iov_offset; |
|
|
|
for (bvec = i->bvec, end = bvec + i->nr_segs; bvec < end; bvec++) { |
|
if (likely(size < bvec->bv_len)) |
|
break; |
|
size -= bvec->bv_len; |
|
} |
|
i->iov_offset = size; |
|
i->nr_segs -= bvec - i->bvec; |
|
i->bvec = bvec; |
|
} |
|
|
|
static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) |
|
{ |
|
const struct iovec *iov, *end; |
|
|
|
if (!i->count) |
|
return; |
|
i->count -= size; |
|
|
|
size += i->iov_offset; // from beginning of current segment |
|
for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { |
|
if (likely(size < iov->iov_len)) |
|
break; |
|
size -= iov->iov_len; |
|
} |
|
i->iov_offset = size; |
|
i->nr_segs -= iov - i->iov; |
|
i->iov = iov; |
|
} |
|
|
|
void iov_iter_advance(struct iov_iter *i, size_t size) |
|
{ |
|
if (unlikely(i->count < size)) |
|
size = i->count; |
|
if (likely(iter_is_ubuf(i)) || unlikely(iov_iter_is_xarray(i))) { |
|
i->iov_offset += size; |
|
i->count -= size; |
|
} else if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { |
|
/* iovec and kvec have identical layouts */ |
|
iov_iter_iovec_advance(i, size); |
|
} else if (iov_iter_is_bvec(i)) { |
|
iov_iter_bvec_advance(i, size); |
|
} else if (iov_iter_is_pipe(i)) { |
|
pipe_advance(i, size); |
|
} else if (iov_iter_is_discard(i)) { |
|
i->count -= size; |
|
} |
|
} |
|
EXPORT_SYMBOL(iov_iter_advance); |
|
|
|
void iov_iter_revert(struct iov_iter *i, size_t unroll) |
|
{ |
|
if (!unroll) |
|
return; |
|
if (WARN_ON(unroll > MAX_RW_COUNT)) |
|
return; |
|
i->count += unroll; |
|
if (unlikely(iov_iter_is_pipe(i))) { |
|
struct pipe_inode_info *pipe = i->pipe; |
|
unsigned int head = pipe->head; |
|
|
|
while (head > i->start_head) { |
|
struct pipe_buffer *b = pipe_buf(pipe, --head); |
|
if (unroll < b->len) { |
|
b->len -= unroll; |
|
i->last_offset = last_offset(b); |
|
i->head = head; |
|
return; |
|
} |
|
unroll -= b->len; |
|
pipe_buf_release(pipe, b); |
|
pipe->head--; |
|
} |
|
i->last_offset = 0; |
|
i->head = head; |
|
return; |
|
} |
|
if (unlikely(iov_iter_is_discard(i))) |
|
return; |
|
if (unroll <= i->iov_offset) { |
|
i->iov_offset -= unroll; |
|
return; |
|
} |
|
unroll -= i->iov_offset; |
|
if (iov_iter_is_xarray(i) || iter_is_ubuf(i)) { |
|
BUG(); /* We should never go beyond the start of the specified |
|
* range since we might then be straying into pages that |
|
* aren't pinned. |
|
*/ |
|
} else if (iov_iter_is_bvec(i)) { |
|
const struct bio_vec *bvec = i->bvec; |
|
while (1) { |
|
size_t n = (--bvec)->bv_len; |
|
i->nr_segs++; |
|
if (unroll <= n) { |
|
i->bvec = bvec; |
|
i->iov_offset = n - unroll; |
|
return; |
|
} |
|
unroll -= n; |
|
} |
|
} else { /* same logics for iovec and kvec */ |
|
const struct iovec *iov = i->iov; |
|
while (1) { |
|
size_t n = (--iov)->iov_len; |
|
i->nr_segs++; |
|
if (unroll <= n) { |
|
i->iov = iov; |
|
i->iov_offset = n - unroll; |
|
return; |
|
} |
|
unroll -= n; |
|
} |
|
} |
|
} |
|
EXPORT_SYMBOL(iov_iter_revert); |
|
|
|
/* |
|
* Return the count of just the current iov_iter segment. |
|
*/ |
|
size_t iov_iter_single_seg_count(const struct iov_iter *i) |
|
{ |
|
if (i->nr_segs > 1) { |
|
if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) |
|
return min(i->count, i->iov->iov_len - i->iov_offset); |
|
if (iov_iter_is_bvec(i)) |
|
return min(i->count, i->bvec->bv_len - i->iov_offset); |
|
} |
|
return i->count; |
|
} |
|
EXPORT_SYMBOL(iov_iter_single_seg_count); |
|
|
|
void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
|
const struct kvec *kvec, unsigned long nr_segs, |
|
size_t count) |
|
{ |
|
WARN_ON(direction & ~(READ | WRITE)); |
|
*i = (struct iov_iter){ |
|
.iter_type = ITER_KVEC, |
|
.data_source = direction, |
|
.kvec = kvec, |
|
.nr_segs = nr_segs, |
|
.iov_offset = 0, |
|
.count = count |
|
}; |
|
} |
|
EXPORT_SYMBOL(iov_iter_kvec); |
|
|
|
void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
|
const struct bio_vec *bvec, unsigned long nr_segs, |
|
size_t count) |
|
{ |
|
WARN_ON(direction & ~(READ | WRITE)); |
|
*i = (struct iov_iter){ |
|
.iter_type = ITER_BVEC, |
|
.data_source = direction, |
|
.bvec = bvec, |
|
.nr_segs = nr_segs, |
|
.iov_offset = 0, |
|
.count = count |
|
}; |
|
} |
|
EXPORT_SYMBOL(iov_iter_bvec); |
|
|
|
void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
|
struct pipe_inode_info *pipe, |
|
size_t count) |
|
{ |
|
BUG_ON(direction != READ); |
|
WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
|
*i = (struct iov_iter){ |
|
.iter_type = ITER_PIPE, |
|
.data_source = false, |
|
.pipe = pipe, |
|
.head = pipe->head, |
|
.start_head = pipe->head, |
|
.last_offset = 0, |
|
.count = count |
|
}; |
|
} |
|
EXPORT_SYMBOL(iov_iter_pipe); |
|
|
|
/** |
|
* iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray |
|
* @i: The iterator to initialise. |
|
* @direction: The direction of the transfer. |
|
* @xarray: The xarray to access. |
|
* @start: The start file position. |
|
* @count: The size of the I/O buffer in bytes. |
|
* |
|
* Set up an I/O iterator to either draw data out of the pages attached to an |
|
* inode or to inject data into those pages. The pages *must* be prevented |
|
* from evaporation, either by taking a ref on them or locking them by the |
|
* caller. |
|
*/ |
|
void iov_iter_xarray(struct iov_iter *i, unsigned int direction, |
|
struct xarray *xarray, loff_t start, size_t count) |
|
{ |
|
BUG_ON(direction & ~1); |
|
*i = (struct iov_iter) { |
|
.iter_type = ITER_XARRAY, |
|
.data_source = direction, |
|
.xarray = xarray, |
|
.xarray_start = start, |
|
.count = count, |
|
.iov_offset = 0 |
|
}; |
|
} |
|
EXPORT_SYMBOL(iov_iter_xarray); |
|
|
|
/** |
|
* iov_iter_discard - Initialise an I/O iterator that discards data |
|
* @i: The iterator to initialise. |
|
* @direction: The direction of the transfer. |
|
* @count: The size of the I/O buffer in bytes. |
|
* |
|
* Set up an I/O iterator that just discards everything that's written to it. |
|
* It's only available as a READ iterator. |
|
*/ |
|
void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) |
|
{ |
|
BUG_ON(direction != READ); |
|
*i = (struct iov_iter){ |
|
.iter_type = ITER_DISCARD, |
|
.data_source = false, |
|
.count = count, |
|
.iov_offset = 0 |
|
}; |
|
} |
|
EXPORT_SYMBOL(iov_iter_discard); |
|
|
|
static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask, |
|
unsigned len_mask) |
|
{ |
|
size_t size = i->count; |
|
size_t skip = i->iov_offset; |
|
unsigned k; |
|
|
|
for (k = 0; k < i->nr_segs; k++, skip = 0) { |
|
size_t len = i->iov[k].iov_len - skip; |
|
|
|
if (len > size) |
|
len = size; |
|
if (len & len_mask) |
|
return false; |
|
if ((unsigned long)(i->iov[k].iov_base + skip) & addr_mask) |
|
return false; |
|
|
|
size -= len; |
|
if (!size) |
|
break; |
|
} |
|
return true; |
|
} |
|
|
|
static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask, |
|
unsigned len_mask) |
|
{ |
|
size_t size = i->count; |
|
unsigned skip = i->iov_offset; |
|
unsigned k; |
|
|
|
for (k = 0; k < i->nr_segs; k++, skip = 0) { |
|
size_t len = i->bvec[k].bv_len - skip; |
|
|
|
if (len > size) |
|
len = size; |
|
if (len & len_mask) |
|
return false; |
|
if ((unsigned long)(i->bvec[k].bv_offset + skip) & addr_mask) |
|
return false; |
|
|
|
size -= len; |
|
if (!size) |
|
break; |
|
} |
|
return true; |
|
} |
|
|
|
/** |
|
* iov_iter_is_aligned() - Check if the addresses and lengths of each segments |
|
* are aligned to the parameters. |
|
* |
|
* @i: &struct iov_iter to restore |
|
* @addr_mask: bit mask to check against the iov element's addresses |
|
* @len_mask: bit mask to check against the iov element's lengths |
|
* |
|
* Return: false if any addresses or lengths intersect with the provided masks |
|
*/ |
|
bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, |
|
unsigned len_mask) |
|
{ |
|
if (likely(iter_is_ubuf(i))) { |
|
if (i->count & len_mask) |
|
return false; |
|
if ((unsigned long)(i->ubuf + i->iov_offset) & addr_mask) |
|
return false; |
|
return true; |
|
} |
|
|
|
if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) |
|
return iov_iter_aligned_iovec(i, addr_mask, len_mask); |
|
|
|
if (iov_iter_is_bvec(i)) |
|
return iov_iter_aligned_bvec(i, addr_mask, len_mask); |
|
|
|
if (iov_iter_is_pipe(i)) { |
|
size_t size = i->count; |
|
|
|
if (size & len_mask) |
|
return false; |
|
if (size && i->last_offset > 0) { |
|
if (i->last_offset & addr_mask) |
|
return false; |
|
} |
|
|
|
return true; |
|
} |
|
|
|
if (iov_iter_is_xarray(i)) { |
|
if (i->count & len_mask) |
|
return false; |
|
if ((i->xarray_start + i->iov_offset) & addr_mask) |
|
return false; |
|
} |
|
|
|
return true; |
|
} |
|
EXPORT_SYMBOL_GPL(iov_iter_is_aligned); |
|
|
|
static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) |
|
{ |
|
unsigned long res = 0; |
|
size_t size = i->count; |
|
size_t skip = i->iov_offset; |
|
unsigned k; |
|
|
|
for (k = 0; k < i->nr_segs; k++, skip = 0) { |
|
size_t len = i->iov[k].iov_len - skip; |
|
if (len) { |
|
res |= (unsigned long)i->iov[k].iov_base + skip; |
|
if (len > size) |
|
len = size; |
|
res |= len; |
|
size -= len; |
|
if (!size) |
|
break; |
|
} |
|
} |
|
return res; |
|
} |
|
|
|
static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) |
|
{ |
|
unsigned res = 0; |
|
size_t size = i->count; |
|
unsigned skip = i->iov_offset; |
|
unsigned k; |
|
|
|
for (k = 0; k < i->nr_segs; k++, skip = 0) { |
|
size_t len = i->bvec[k].bv_len - skip; |
|
res |= (unsigned long)i->bvec[k].bv_offset + skip; |
|
if (len > size) |
|
len = size; |
|
res |= len; |
|
size -= len; |
|
if (!size) |
|
break; |
|
} |
|
return res; |
|
} |
|
|
|
unsigned long iov_iter_alignment(const struct iov_iter *i) |
|
{ |
|
if (likely(iter_is_ubuf(i))) { |
|
size_t size = i->count; |
|
if (size) |
|
return ((unsigned long)i->ubuf + i->iov_offset) | size; |
|
return 0; |
|
} |
|
|
|
/* iovec and kvec have identical layouts */ |
|
if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) |
|
return iov_iter_alignment_iovec(i); |
|
|
|
if (iov_iter_is_bvec(i)) |
|
return iov_iter_alignment_bvec(i); |
|
|
|
if (iov_iter_is_pipe(i)) { |
|
size_t size = i->count; |
|
|
|
if (size && i->last_offset > 0) |
|
return size | i->last_offset; |
|
return size; |
|
} |
|
|
|
if (iov_iter_is_xarray(i)) |
|
return (i->xarray_start + i->iov_offset) | i->count; |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL(iov_iter_alignment); |
|
|
|
unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
|
{ |
|
unsigned long res = 0; |
|
unsigned long v = 0; |
|
size_t size = i->count; |
|
unsigned k; |
|
|
|
if (iter_is_ubuf(i)) |
|
return 0; |
|
|
|
if (WARN_ON(!iter_is_iovec(i))) |
|
return ~0U; |
|
|
|
for (k = 0; k < i->nr_segs; k++) { |
|
if (i->iov[k].iov_len) { |
|
unsigned long base = (unsigned long)i->iov[k].iov_base; |
|
if (v) // if not the first one |
|
res |= base | v; // this start | previous end |
|
v = base + i->iov[k].iov_len; |
|
if (size <= i->iov[k].iov_len) |
|
break; |
|
size -= i->iov[k].iov_len; |
|
} |
|
} |
|
return res; |
|
} |
|
EXPORT_SYMBOL(iov_iter_gap_alignment); |
|
|
|
static int want_pages_array(struct page ***res, size_t size, |
|
size_t start, unsigned int maxpages) |
|
{ |
|
unsigned int count = DIV_ROUND_UP(size + start, PAGE_SIZE); |
|
|
|
if (count > maxpages) |
|
count = maxpages; |
|
WARN_ON(!count); // caller should've prevented that |
|
if (!*res) { |
|
*res = kvmalloc_array(count, sizeof(struct page *), GFP_KERNEL); |
|
if (!*res) |
|
return 0; |
|
} |
|
return count; |
|
} |
|
|
|
static ssize_t pipe_get_pages(struct iov_iter *i, |
|
struct page ***pages, size_t maxsize, unsigned maxpages, |
|
size_t *start) |
|
{ |
|
unsigned int npages, count, off, chunk; |
|
struct page **p; |
|
size_t left; |
|
|
|
if (!sanity(i)) |
|
return -EFAULT; |
|
|
|
*start = off = pipe_npages(i, &npages); |
|
if (!npages) |
|
return -EFAULT; |
|
count = want_pages_array(pages, maxsize, off, min(npages, maxpages)); |
|
if (!count) |
|
return -ENOMEM; |
|
p = *pages; |
|
for (npages = 0, left = maxsize ; npages < count; npages++, left -= chunk) { |
|
struct page *page = append_pipe(i, left, &off); |
|
if (!page) |
|
break; |
|
chunk = min_t(size_t, left, PAGE_SIZE - off); |
|
get_page(*p++ = page); |
|
} |
|
if (!npages) |
|
return -EFAULT; |
|
return maxsize - left; |
|
} |
|
|
|
static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
|
pgoff_t index, unsigned int nr_pages) |
|
{ |
|
XA_STATE(xas, xa, index); |
|
struct page *page; |
|
unsigned int ret = 0; |
|
|
|
rcu_read_lock(); |
|
for (page = xas_load(&xas); page; page = xas_next(&xas)) { |
|
if (xas_retry(&xas, page)) |
|
continue; |
|
|
|
/* Has the page moved or been split? */ |
|
if (unlikely(page != xas_reload(&xas))) { |
|
xas_reset(&xas); |
|
continue; |
|
} |
|
|
|
pages[ret] = find_subpage(page, xas.xa_index); |
|
get_page(pages[ret]); |
|
if (++ret == nr_pages) |
|
break; |
|
} |
|
rcu_read_unlock(); |
|
return ret; |
|
} |
|
|
|
static ssize_t iter_xarray_get_pages(struct iov_iter *i, |
|
struct page ***pages, size_t maxsize, |
|
unsigned maxpages, size_t *_start_offset) |
|
{ |
|
unsigned nr, offset, count; |
|
pgoff_t index; |
|
loff_t pos; |
|
|
|
pos = i->xarray_start + i->iov_offset; |
|
index = pos >> PAGE_SHIFT; |
|
offset = pos & ~PAGE_MASK; |
|
*_start_offset = offset; |
|
|
|
count = want_pages_array(pages, maxsize, offset, maxpages); |
|
if (!count) |
|
return -ENOMEM; |
|
nr = iter_xarray_populate_pages(*pages, i->xarray, index, count); |
|
if (nr == 0) |
|
return 0; |
|
|
|
maxsize = min_t(size_t, nr * PAGE_SIZE - offset, maxsize); |
|
i->iov_offset += maxsize; |
|
i->count -= maxsize; |
|
return maxsize; |
|
} |
|
|
|
/* must be done on non-empty ITER_UBUF or ITER_IOVEC one */ |
|
static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size) |
|
{ |
|
size_t skip; |
|
long k; |
|
|
|
if (iter_is_ubuf(i)) |
|
return (unsigned long)i->ubuf + i->iov_offset; |
|
|
|
for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { |
|
size_t len = i->iov[k].iov_len - skip; |
|
|
|
if (unlikely(!len)) |
|
continue; |
|
if (*size > len) |
|
*size = len; |
|
return (unsigned long)i->iov[k].iov_base + skip; |
|
} |
|
BUG(); // if it had been empty, we wouldn't get called |
|
} |
|
|
|
/* must be done on non-empty ITER_BVEC one */ |
|
static struct page *first_bvec_segment(const struct iov_iter *i, |
|
size_t *size, size_t *start) |
|
{ |
|
struct page *page; |
|
size_t skip = i->iov_offset, len; |
|
|
|
len = i->bvec->bv_len - skip; |
|
if (*size > len) |
|
*size = len; |
|
skip += i->bvec->bv_offset; |
|
page = i->bvec->bv_page + skip / PAGE_SIZE; |
|
*start = skip % PAGE_SIZE; |
|
return page; |
|
} |
|
|
|
static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, |
|
struct page ***pages, size_t maxsize, |
|
unsigned int maxpages, size_t *start) |
|
{ |
|
unsigned int n; |
|
|
|
if (maxsize > i->count) |
|
maxsize = i->count; |
|
if (!maxsize) |
|
return 0; |
|
if (maxsize > MAX_RW_COUNT) |
|
maxsize = MAX_RW_COUNT; |
|
|
|
if (likely(user_backed_iter(i))) { |
|
unsigned int gup_flags = 0; |
|
unsigned long addr; |
|
int res; |
|
|
|
if (iov_iter_rw(i) != WRITE) |
|
gup_flags |= FOLL_WRITE; |
|
if (i->nofault) |
|
gup_flags |= FOLL_NOFAULT; |
|
|
|
addr = first_iovec_segment(i, &maxsize); |
|
*start = addr % PAGE_SIZE; |
|
addr &= PAGE_MASK; |
|
n = want_pages_array(pages, maxsize, *start, maxpages); |
|
if (!n) |
|
return -ENOMEM; |
|
res = get_user_pages_fast(addr, n, gup_flags, *pages); |
|
if (unlikely(res <= 0)) |
|
return res; |
|
maxsize = min_t(size_t, maxsize, res * PAGE_SIZE - *start); |
|
iov_iter_advance(i, maxsize); |
|
return maxsize; |
|
} |
|
if (iov_iter_is_bvec(i)) { |
|
struct page **p; |
|
struct page *page; |
|
|
|
page = first_bvec_segment(i, &maxsize, start); |
|
n = want_pages_array(pages, maxsize, *start, maxpages); |
|
if (!n) |
|
return -ENOMEM; |
|
p = *pages; |
|
for (int k = 0; k < n; k++) |
|
get_page(p[k] = page + k); |
|
maxsize = min_t(size_t, maxsize, n * PAGE_SIZE - *start); |
|
i->count -= maxsize; |
|
i->iov_offset += maxsize; |
|
if (i->iov_offset == i->bvec->bv_len) { |
|
i->iov_offset = 0; |
|
i->bvec++; |
|
i->nr_segs--; |
|
} |
|
return maxsize; |
|
} |
|
if (iov_iter_is_pipe(i)) |
|
return pipe_get_pages(i, pages, maxsize, maxpages, start); |
|
if (iov_iter_is_xarray(i)) |
|
return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); |
|
return -EFAULT; |
|
} |
|
|
|
ssize_t iov_iter_get_pages2(struct iov_iter *i, |
|
struct page **pages, size_t maxsize, unsigned maxpages, |
|
size_t *start) |
|
{ |
|
if (!maxpages) |
|
return 0; |
|
BUG_ON(!pages); |
|
|
|
return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start); |
|
} |
|
EXPORT_SYMBOL(iov_iter_get_pages2); |
|
|
|
ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, |
|
struct page ***pages, size_t maxsize, |
|
size_t *start) |
|
{ |
|
ssize_t len; |
|
|
|
*pages = NULL; |
|
|
|
len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start); |
|
if (len <= 0) { |
|
kvfree(*pages); |
|
*pages = NULL; |
|
} |
|
return len; |
|
} |
|
EXPORT_SYMBOL(iov_iter_get_pages_alloc2); |
|
|
|
size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
|
struct iov_iter *i) |
|
{ |
|
__wsum sum, next; |
|
sum = *csum; |
|
if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
|
WARN_ON(1); |
|
return 0; |
|
} |
|
iterate_and_advance(i, bytes, base, len, off, ({ |
|
next = csum_and_copy_from_user(base, addr + off, len); |
|
sum = csum_block_add(sum, next, off); |
|
next ? 0 : len; |
|
}), ({ |
|
sum = csum_and_memcpy(addr + off, base, len, sum, off); |
|
}) |
|
) |
|
*csum = sum; |
|
return bytes; |
|
} |
|
EXPORT_SYMBOL(csum_and_copy_from_iter); |
|
|
|
size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
|
struct iov_iter *i) |
|
{ |
|
struct csum_state *csstate = _csstate; |
|
__wsum sum, next; |
|
|
|
if (unlikely(iov_iter_is_discard(i))) { |
|
WARN_ON(1); /* for now */ |
|
return 0; |
|
} |
|
|
|
sum = csum_shift(csstate->csum, csstate->off); |
|
if (unlikely(iov_iter_is_pipe(i))) |
|
bytes = csum_and_copy_to_pipe_iter(addr, bytes, i, &sum); |
|
else iterate_and_advance(i, bytes, base, len, off, ({ |
|
next = csum_and_copy_to_user(addr + off, base, len); |
|
sum = csum_block_add(sum, next, off); |
|
next ? 0 : len; |
|
}), ({ |
|
sum = csum_and_memcpy(base, addr + off, len, sum, off); |
|
}) |
|
) |
|
csstate->csum = csum_shift(sum, csstate->off); |
|
csstate->off += bytes; |
|
return bytes; |
|
} |
|
EXPORT_SYMBOL(csum_and_copy_to_iter); |
|
|
|
size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
|
struct iov_iter *i) |
|
{ |
|
#ifdef CONFIG_CRYPTO_HASH |
|
struct ahash_request *hash = hashp; |
|
struct scatterlist sg; |
|
size_t copied; |
|
|
|
copied = copy_to_iter(addr, bytes, i); |
|
sg_init_one(&sg, addr, copied); |
|
ahash_request_set_crypt(hash, &sg, NULL, copied); |
|
crypto_ahash_update(hash); |
|
return copied; |
|
#else |
|
return 0; |
|
#endif |
|
} |
|
EXPORT_SYMBOL(hash_and_copy_to_iter); |
|
|
|
static int iov_npages(const struct iov_iter *i, int maxpages) |
|
{ |
|
size_t skip = i->iov_offset, size = i->count; |
|
const struct iovec *p; |
|
int npages = 0; |
|
|
|
for (p = i->iov; size; skip = 0, p++) { |
|
unsigned offs = offset_in_page(p->iov_base + skip); |
|
size_t len = min(p->iov_len - skip, size); |
|
|
|
if (len) { |
|
size -= len; |
|
npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); |
|
if (unlikely(npages > maxpages)) |
|
return maxpages; |
|
} |
|
} |
|
return npages; |
|
} |
|
|
|
static int bvec_npages(const struct iov_iter *i, int maxpages) |
|
{ |
|
size_t skip = i->iov_offset, size = i->count; |
|
const struct bio_vec *p; |
|
int npages = 0; |
|
|
|
for (p = i->bvec; size; skip = 0, p++) { |
|
unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; |
|
size_t len = min(p->bv_len - skip, size); |
|
|
|
size -= len; |
|
npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); |
|
if (unlikely(npages > maxpages)) |
|
return maxpages; |
|
} |
|
return npages; |
|
} |
|
|
|
int iov_iter_npages(const struct iov_iter *i, int maxpages) |
|
{ |
|
if (unlikely(!i->count)) |
|
return 0; |
|
if (likely(iter_is_ubuf(i))) { |
|
unsigned offs = offset_in_page(i->ubuf + i->iov_offset); |
|
int npages = DIV_ROUND_UP(offs + i->count, PAGE_SIZE); |
|
return min(npages, maxpages); |
|
} |
|
/* iovec and kvec have identical layouts */ |
|
if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) |
|
return iov_npages(i, maxpages); |
|
if (iov_iter_is_bvec(i)) |
|
return bvec_npages(i, maxpages); |
|
if (iov_iter_is_pipe(i)) { |
|
int npages; |
|
|
|
if (!sanity(i)) |
|
return 0; |
|
|
|
pipe_npages(i, &npages); |
|
return min(npages, maxpages); |
|
} |
|
if (iov_iter_is_xarray(i)) { |
|
unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; |
|
int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); |
|
return min(npages, maxpages); |
|
} |
|
return 0; |
|
} |
|
EXPORT_SYMBOL(iov_iter_npages); |
|
|
|
const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) |
|
{ |
|
*new = *old; |
|
if (unlikely(iov_iter_is_pipe(new))) { |
|
WARN_ON(1); |
|
return NULL; |
|
} |
|
if (iov_iter_is_bvec(new)) |
|
return new->bvec = kmemdup(new->bvec, |
|
new->nr_segs * sizeof(struct bio_vec), |
|
flags); |
|
else if (iov_iter_is_kvec(new) || iter_is_iovec(new)) |
|
/* iovec and kvec have identical layout */ |
|
return new->iov = kmemdup(new->iov, |
|
new->nr_segs * sizeof(struct iovec), |
|
flags); |
|
return NULL; |
|
} |
|
EXPORT_SYMBOL(dup_iter); |
|
|
|
static int copy_compat_iovec_from_user(struct iovec *iov, |
|
const struct iovec __user *uvec, unsigned long nr_segs) |
|
{ |
|
const struct compat_iovec __user *uiov = |
|
(const struct compat_iovec __user *)uvec; |
|
int ret = -EFAULT, i; |
|
|
|
if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
|
return -EFAULT; |
|
|
|
for (i = 0; i < nr_segs; i++) { |
|
compat_uptr_t buf; |
|
compat_ssize_t len; |
|
|
|
unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); |
|
unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); |
|
|
|
/* check for compat_size_t not fitting in compat_ssize_t .. */ |
|
if (len < 0) { |
|
ret = -EINVAL; |
|
goto uaccess_end; |
|
} |
|
iov[i].iov_base = compat_ptr(buf); |
|
iov[i].iov_len = len; |
|
} |
|
|
|
ret = 0; |
|
uaccess_end: |
|
user_access_end(); |
|
return ret; |
|
} |
|
|
|
static int copy_iovec_from_user(struct iovec *iov, |
|
const struct iovec __user *uvec, unsigned long nr_segs) |
|
{ |
|
unsigned long seg; |
|
|
|
if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
|
return -EFAULT; |
|
for (seg = 0; seg < nr_segs; seg++) { |
|
if ((ssize_t)iov[seg].iov_len < 0) |
|
return -EINVAL; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
struct iovec *iovec_from_user(const struct iovec __user *uvec, |
|
unsigned long nr_segs, unsigned long fast_segs, |
|
struct iovec *fast_iov, bool compat) |
|
{ |
|
struct iovec *iov = fast_iov; |
|
int ret; |
|
|
|
/* |
|
* SuS says "The readv() function *may* fail if the iovcnt argument was |
|
* less than or equal to 0, or greater than {IOV_MAX}. Linux has |
|
* traditionally returned zero for zero segments, so... |
|
*/ |
|
if (nr_segs == 0) |
|
return iov; |
|
if (nr_segs > UIO_MAXIOV) |
|
return ERR_PTR(-EINVAL); |
|
if (nr_segs > fast_segs) { |
|
iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); |
|
if (!iov) |
|
return ERR_PTR(-ENOMEM); |
|
} |
|
|
|
if (compat) |
|
ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); |
|
else |
|
ret = copy_iovec_from_user(iov, uvec, nr_segs); |
|
if (ret) { |
|
if (iov != fast_iov) |
|
kfree(iov); |
|
return ERR_PTR(ret); |
|
} |
|
|
|
return iov; |
|
} |
|
|
|
ssize_t __import_iovec(int type, const struct iovec __user *uvec, |
|
unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, |
|
struct iov_iter *i, bool compat) |
|
{ |
|
ssize_t total_len = 0; |
|
unsigned long seg; |
|
struct iovec *iov; |
|
|
|
iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); |
|
if (IS_ERR(iov)) { |
|
*iovp = NULL; |
|
return PTR_ERR(iov); |
|
} |
|
|
|
/* |
|
* According to the Single Unix Specification we should return EINVAL if |
|
* an element length is < 0 when cast to ssize_t or if the total length |
|
* would overflow the ssize_t return value of the system call. |
|
* |
|
* Linux caps all read/write calls to MAX_RW_COUNT, and avoids the |
|
* overflow case. |
|
*/ |
|
for (seg = 0; seg < nr_segs; seg++) { |
|
ssize_t len = (ssize_t)iov[seg].iov_len; |
|
|
|
if (!access_ok(iov[seg].iov_base, len)) { |
|
if (iov != *iovp) |
|
kfree(iov); |
|
*iovp = NULL; |
|
return -EFAULT; |
|
} |
|
|
|
if (len > MAX_RW_COUNT - total_len) { |
|
len = MAX_RW_COUNT - total_len; |
|
iov[seg].iov_len = len; |
|
} |
|
total_len += len; |
|
} |
|
|
|
iov_iter_init(i, type, iov, nr_segs, total_len); |
|
if (iov == *iovp) |
|
*iovp = NULL; |
|
else |
|
*iovp = iov; |
|
return total_len; |
|
} |
|
|
|
/** |
|
* import_iovec() - Copy an array of &struct iovec from userspace |
|
* into the kernel, check that it is valid, and initialize a new |
|
* &struct iov_iter iterator to access it. |
|
* |
|
* @type: One of %READ or %WRITE. |
|
* @uvec: Pointer to the userspace array. |
|
* @nr_segs: Number of elements in userspace array. |
|
* @fast_segs: Number of elements in @iov. |
|
* @iovp: (input and output parameter) Pointer to pointer to (usually small |
|
* on-stack) kernel array. |
|
* @i: Pointer to iterator that will be initialized on success. |
|
* |
|
* If the array pointed to by *@iov is large enough to hold all @nr_segs, |
|
* then this function places %NULL in *@iov on return. Otherwise, a new |
|
* array will be allocated and the result placed in *@iov. This means that |
|
* the caller may call kfree() on *@iov regardless of whether the small |
|
* on-stack array was used or not (and regardless of whether this function |
|
* returns an error or not). |
|
* |
|
* Return: Negative error code on error, bytes imported on success |
|
*/ |
|
ssize_t import_iovec(int type, const struct iovec __user *uvec, |
|
unsigned nr_segs, unsigned fast_segs, |
|
struct iovec **iovp, struct iov_iter *i) |
|
{ |
|
return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
|
in_compat_syscall()); |
|
} |
|
EXPORT_SYMBOL(import_iovec); |
|
|
|
int import_single_range(int rw, void __user *buf, size_t len, |
|
struct iovec *iov, struct iov_iter *i) |
|
{ |
|
if (len > MAX_RW_COUNT) |
|
len = MAX_RW_COUNT; |
|
if (unlikely(!access_ok(buf, len))) |
|
return -EFAULT; |
|
|
|
iov->iov_base = buf; |
|
iov->iov_len = len; |
|
iov_iter_init(i, rw, iov, 1, len); |
|
return 0; |
|
} |
|
EXPORT_SYMBOL(import_single_range); |
|
|
|
/** |
|
* iov_iter_restore() - Restore a &struct iov_iter to the same state as when |
|
* iov_iter_save_state() was called. |
|
* |
|
* @i: &struct iov_iter to restore |
|
* @state: state to restore from |
|
* |
|
* Used after iov_iter_save_state() to bring restore @i, if operations may |
|
* have advanced it. |
|
* |
|
* Note: only works on ITER_IOVEC, ITER_BVEC, and ITER_KVEC |
|
*/ |
|
void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state) |
|
{ |
|
if (WARN_ON_ONCE(!iov_iter_is_bvec(i) && !iter_is_iovec(i)) && |
|
!iov_iter_is_kvec(i) && !iter_is_ubuf(i)) |
|
return; |
|
i->iov_offset = state->iov_offset; |
|
i->count = state->count; |
|
if (iter_is_ubuf(i)) |
|
return; |
|
/* |
|
* For the *vec iters, nr_segs + iov is constant - if we increment |
|
* the vec, then we also decrement the nr_segs count. Hence we don't |
|
* need to track both of these, just one is enough and we can deduct |
|
* the other from that. ITER_KVEC and ITER_IOVEC are the same struct |
|
* size, so we can just increment the iov pointer as they are unionzed. |
|
* ITER_BVEC _may_ be the same size on some archs, but on others it is |
|
* not. Be safe and handle it separately. |
|
*/ |
|
BUILD_BUG_ON(sizeof(struct iovec) != sizeof(struct kvec)); |
|
if (iov_iter_is_bvec(i)) |
|
i->bvec -= state->nr_segs - i->nr_segs; |
|
else |
|
i->iov -= state->nr_segs - i->nr_segs; |
|
i->nr_segs = state->nr_segs; |
|
}
|
|
|