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551 lines
13 KiB
551 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/kernel.h> |
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#include <linux/errno.h> |
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#include <linux/fs.h> |
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#include <linux/file.h> |
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#include <linux/mm.h> |
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#include <linux/slab.h> |
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#include <linux/namei.h> |
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#include <linux/poll.h> |
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#include <linux/io_uring.h> |
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#include <uapi/linux/io_uring.h> |
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|
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#include "io_uring.h" |
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#include "opdef.h" |
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#include "kbuf.h" |
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#define IO_BUFFER_LIST_BUF_PER_PAGE (PAGE_SIZE / sizeof(struct io_uring_buf)) |
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#define BGID_ARRAY 64 |
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struct io_provide_buf { |
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struct file *file; |
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__u64 addr; |
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__u32 len; |
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__u32 bgid; |
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__u16 nbufs; |
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__u16 bid; |
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}; |
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static inline struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx, |
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unsigned int bgid) |
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{ |
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if (ctx->io_bl && bgid < BGID_ARRAY) |
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return &ctx->io_bl[bgid]; |
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return xa_load(&ctx->io_bl_xa, bgid); |
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} |
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static int io_buffer_add_list(struct io_ring_ctx *ctx, |
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struct io_buffer_list *bl, unsigned int bgid) |
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{ |
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bl->bgid = bgid; |
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if (bgid < BGID_ARRAY) |
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return 0; |
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return xa_err(xa_store(&ctx->io_bl_xa, bgid, bl, GFP_KERNEL)); |
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} |
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void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags) |
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{ |
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struct io_ring_ctx *ctx = req->ctx; |
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struct io_buffer_list *bl; |
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struct io_buffer *buf; |
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/* |
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* For legacy provided buffer mode, don't recycle if we already did |
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* IO to this buffer. For ring-mapped provided buffer mode, we should |
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* increment ring->head to explicitly monopolize the buffer to avoid |
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* multiple use. |
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*/ |
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if (req->flags & REQ_F_PARTIAL_IO) |
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return; |
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io_ring_submit_lock(ctx, issue_flags); |
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buf = req->kbuf; |
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bl = io_buffer_get_list(ctx, buf->bgid); |
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list_add(&buf->list, &bl->buf_list); |
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req->flags &= ~REQ_F_BUFFER_SELECTED; |
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req->buf_index = buf->bgid; |
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io_ring_submit_unlock(ctx, issue_flags); |
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return; |
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} |
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unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags) |
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{ |
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unsigned int cflags; |
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/* |
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* We can add this buffer back to two lists: |
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* |
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* 1) The io_buffers_cache list. This one is protected by the |
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* ctx->uring_lock. If we already hold this lock, add back to this |
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* list as we can grab it from issue as well. |
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* 2) The io_buffers_comp list. This one is protected by the |
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* ctx->completion_lock. |
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* |
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* We migrate buffers from the comp_list to the issue cache list |
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* when we need one. |
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*/ |
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if (req->flags & REQ_F_BUFFER_RING) { |
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/* no buffers to recycle for this case */ |
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cflags = __io_put_kbuf_list(req, NULL); |
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} else if (issue_flags & IO_URING_F_UNLOCKED) { |
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struct io_ring_ctx *ctx = req->ctx; |
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spin_lock(&ctx->completion_lock); |
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cflags = __io_put_kbuf_list(req, &ctx->io_buffers_comp); |
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spin_unlock(&ctx->completion_lock); |
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} else { |
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lockdep_assert_held(&req->ctx->uring_lock); |
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cflags = __io_put_kbuf_list(req, &req->ctx->io_buffers_cache); |
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} |
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return cflags; |
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} |
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static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len, |
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struct io_buffer_list *bl) |
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{ |
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if (!list_empty(&bl->buf_list)) { |
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struct io_buffer *kbuf; |
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kbuf = list_first_entry(&bl->buf_list, struct io_buffer, list); |
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list_del(&kbuf->list); |
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if (*len == 0 || *len > kbuf->len) |
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*len = kbuf->len; |
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req->flags |= REQ_F_BUFFER_SELECTED; |
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req->kbuf = kbuf; |
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req->buf_index = kbuf->bid; |
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return u64_to_user_ptr(kbuf->addr); |
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} |
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return NULL; |
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} |
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static void __user *io_ring_buffer_select(struct io_kiocb *req, size_t *len, |
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struct io_buffer_list *bl, |
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unsigned int issue_flags) |
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{ |
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struct io_uring_buf_ring *br = bl->buf_ring; |
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struct io_uring_buf *buf; |
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__u16 head = bl->head; |
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if (unlikely(smp_load_acquire(&br->tail) == head)) |
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return NULL; |
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head &= bl->mask; |
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if (head < IO_BUFFER_LIST_BUF_PER_PAGE) { |
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buf = &br->bufs[head]; |
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} else { |
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int off = head & (IO_BUFFER_LIST_BUF_PER_PAGE - 1); |
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int index = head / IO_BUFFER_LIST_BUF_PER_PAGE; |
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buf = page_address(bl->buf_pages[index]); |
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buf += off; |
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} |
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if (*len == 0 || *len > buf->len) |
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*len = buf->len; |
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req->flags |= REQ_F_BUFFER_RING; |
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req->buf_list = bl; |
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req->buf_index = buf->bid; |
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if (issue_flags & IO_URING_F_UNLOCKED || !file_can_poll(req->file)) { |
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/* |
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* If we came in unlocked, we have no choice but to consume the |
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* buffer here, otherwise nothing ensures that the buffer won't |
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* get used by others. This does mean it'll be pinned until the |
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* IO completes, coming in unlocked means we're being called from |
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* io-wq context and there may be further retries in async hybrid |
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* mode. For the locked case, the caller must call commit when |
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* the transfer completes (or if we get -EAGAIN and must poll of |
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* retry). |
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*/ |
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req->buf_list = NULL; |
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bl->head++; |
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} |
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return u64_to_user_ptr(buf->addr); |
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} |
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void __user *io_buffer_select(struct io_kiocb *req, size_t *len, |
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unsigned int issue_flags) |
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{ |
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struct io_ring_ctx *ctx = req->ctx; |
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struct io_buffer_list *bl; |
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void __user *ret = NULL; |
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io_ring_submit_lock(req->ctx, issue_flags); |
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bl = io_buffer_get_list(ctx, req->buf_index); |
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if (likely(bl)) { |
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if (bl->buf_nr_pages) |
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ret = io_ring_buffer_select(req, len, bl, issue_flags); |
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else |
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ret = io_provided_buffer_select(req, len, bl); |
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} |
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io_ring_submit_unlock(req->ctx, issue_flags); |
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return ret; |
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} |
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static __cold int io_init_bl_list(struct io_ring_ctx *ctx) |
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{ |
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int i; |
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ctx->io_bl = kcalloc(BGID_ARRAY, sizeof(struct io_buffer_list), |
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GFP_KERNEL); |
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if (!ctx->io_bl) |
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return -ENOMEM; |
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for (i = 0; i < BGID_ARRAY; i++) { |
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INIT_LIST_HEAD(&ctx->io_bl[i].buf_list); |
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ctx->io_bl[i].bgid = i; |
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} |
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return 0; |
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} |
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static int __io_remove_buffers(struct io_ring_ctx *ctx, |
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struct io_buffer_list *bl, unsigned nbufs) |
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{ |
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unsigned i = 0; |
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/* shouldn't happen */ |
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if (!nbufs) |
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return 0; |
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if (bl->buf_nr_pages) { |
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int j; |
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i = bl->buf_ring->tail - bl->head; |
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for (j = 0; j < bl->buf_nr_pages; j++) |
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unpin_user_page(bl->buf_pages[j]); |
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kvfree(bl->buf_pages); |
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bl->buf_pages = NULL; |
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bl->buf_nr_pages = 0; |
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/* make sure it's seen as empty */ |
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INIT_LIST_HEAD(&bl->buf_list); |
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return i; |
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} |
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/* the head kbuf is the list itself */ |
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while (!list_empty(&bl->buf_list)) { |
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struct io_buffer *nxt; |
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nxt = list_first_entry(&bl->buf_list, struct io_buffer, list); |
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list_del(&nxt->list); |
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if (++i == nbufs) |
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return i; |
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cond_resched(); |
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} |
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i++; |
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return i; |
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} |
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void io_destroy_buffers(struct io_ring_ctx *ctx) |
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{ |
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struct io_buffer_list *bl; |
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unsigned long index; |
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int i; |
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for (i = 0; i < BGID_ARRAY; i++) { |
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if (!ctx->io_bl) |
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break; |
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__io_remove_buffers(ctx, &ctx->io_bl[i], -1U); |
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} |
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xa_for_each(&ctx->io_bl_xa, index, bl) { |
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xa_erase(&ctx->io_bl_xa, bl->bgid); |
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__io_remove_buffers(ctx, bl, -1U); |
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kfree(bl); |
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} |
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while (!list_empty(&ctx->io_buffers_pages)) { |
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struct page *page; |
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page = list_first_entry(&ctx->io_buffers_pages, struct page, lru); |
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list_del_init(&page->lru); |
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__free_page(page); |
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} |
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} |
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int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
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{ |
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struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); |
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u64 tmp; |
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if (sqe->rw_flags || sqe->addr || sqe->len || sqe->off || |
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sqe->splice_fd_in) |
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return -EINVAL; |
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tmp = READ_ONCE(sqe->fd); |
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if (!tmp || tmp > USHRT_MAX) |
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return -EINVAL; |
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memset(p, 0, sizeof(*p)); |
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p->nbufs = tmp; |
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p->bgid = READ_ONCE(sqe->buf_group); |
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return 0; |
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} |
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int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags) |
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{ |
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struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); |
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struct io_ring_ctx *ctx = req->ctx; |
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struct io_buffer_list *bl; |
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int ret = 0; |
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io_ring_submit_lock(ctx, issue_flags); |
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ret = -ENOENT; |
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bl = io_buffer_get_list(ctx, p->bgid); |
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if (bl) { |
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ret = -EINVAL; |
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/* can't use provide/remove buffers command on mapped buffers */ |
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if (!bl->buf_nr_pages) |
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ret = __io_remove_buffers(ctx, bl, p->nbufs); |
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} |
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if (ret < 0) |
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req_set_fail(req); |
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/* complete before unlock, IOPOLL may need the lock */ |
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io_req_set_res(req, ret, 0); |
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__io_req_complete(req, issue_flags); |
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io_ring_submit_unlock(ctx, issue_flags); |
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return IOU_ISSUE_SKIP_COMPLETE; |
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} |
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int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
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{ |
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unsigned long size, tmp_check; |
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struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); |
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u64 tmp; |
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if (sqe->rw_flags || sqe->splice_fd_in) |
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return -EINVAL; |
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tmp = READ_ONCE(sqe->fd); |
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if (!tmp || tmp > USHRT_MAX) |
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return -E2BIG; |
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p->nbufs = tmp; |
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p->addr = READ_ONCE(sqe->addr); |
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p->len = READ_ONCE(sqe->len); |
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if (check_mul_overflow((unsigned long)p->len, (unsigned long)p->nbufs, |
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&size)) |
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return -EOVERFLOW; |
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if (check_add_overflow((unsigned long)p->addr, size, &tmp_check)) |
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return -EOVERFLOW; |
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size = (unsigned long)p->len * p->nbufs; |
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if (!access_ok(u64_to_user_ptr(p->addr), size)) |
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return -EFAULT; |
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p->bgid = READ_ONCE(sqe->buf_group); |
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tmp = READ_ONCE(sqe->off); |
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if (tmp > USHRT_MAX) |
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return -E2BIG; |
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if (tmp + p->nbufs >= USHRT_MAX) |
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return -EINVAL; |
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p->bid = tmp; |
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return 0; |
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} |
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static int io_refill_buffer_cache(struct io_ring_ctx *ctx) |
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{ |
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struct io_buffer *buf; |
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struct page *page; |
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int bufs_in_page; |
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/* |
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* Completions that don't happen inline (eg not under uring_lock) will |
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* add to ->io_buffers_comp. If we don't have any free buffers, check |
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* the completion list and splice those entries first. |
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*/ |
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if (!list_empty_careful(&ctx->io_buffers_comp)) { |
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spin_lock(&ctx->completion_lock); |
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if (!list_empty(&ctx->io_buffers_comp)) { |
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list_splice_init(&ctx->io_buffers_comp, |
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&ctx->io_buffers_cache); |
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spin_unlock(&ctx->completion_lock); |
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return 0; |
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} |
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spin_unlock(&ctx->completion_lock); |
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} |
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/* |
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* No free buffers and no completion entries either. Allocate a new |
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* page worth of buffer entries and add those to our freelist. |
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*/ |
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page = alloc_page(GFP_KERNEL_ACCOUNT); |
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if (!page) |
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return -ENOMEM; |
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list_add(&page->lru, &ctx->io_buffers_pages); |
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buf = page_address(page); |
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bufs_in_page = PAGE_SIZE / sizeof(*buf); |
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while (bufs_in_page) { |
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list_add_tail(&buf->list, &ctx->io_buffers_cache); |
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buf++; |
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bufs_in_page--; |
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} |
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return 0; |
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} |
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static int io_add_buffers(struct io_ring_ctx *ctx, struct io_provide_buf *pbuf, |
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struct io_buffer_list *bl) |
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{ |
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struct io_buffer *buf; |
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u64 addr = pbuf->addr; |
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int i, bid = pbuf->bid; |
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for (i = 0; i < pbuf->nbufs; i++) { |
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if (list_empty(&ctx->io_buffers_cache) && |
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io_refill_buffer_cache(ctx)) |
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break; |
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buf = list_first_entry(&ctx->io_buffers_cache, struct io_buffer, |
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list); |
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list_move_tail(&buf->list, &bl->buf_list); |
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buf->addr = addr; |
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buf->len = min_t(__u32, pbuf->len, MAX_RW_COUNT); |
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buf->bid = bid; |
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buf->bgid = pbuf->bgid; |
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addr += pbuf->len; |
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bid++; |
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cond_resched(); |
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} |
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return i ? 0 : -ENOMEM; |
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} |
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int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags) |
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{ |
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struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); |
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struct io_ring_ctx *ctx = req->ctx; |
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struct io_buffer_list *bl; |
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int ret = 0; |
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io_ring_submit_lock(ctx, issue_flags); |
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if (unlikely(p->bgid < BGID_ARRAY && !ctx->io_bl)) { |
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ret = io_init_bl_list(ctx); |
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if (ret) |
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goto err; |
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} |
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bl = io_buffer_get_list(ctx, p->bgid); |
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if (unlikely(!bl)) { |
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bl = kzalloc(sizeof(*bl), GFP_KERNEL_ACCOUNT); |
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if (!bl) { |
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ret = -ENOMEM; |
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goto err; |
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} |
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INIT_LIST_HEAD(&bl->buf_list); |
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ret = io_buffer_add_list(ctx, bl, p->bgid); |
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if (ret) { |
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kfree(bl); |
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goto err; |
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} |
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} |
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/* can't add buffers via this command for a mapped buffer ring */ |
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if (bl->buf_nr_pages) { |
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ret = -EINVAL; |
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goto err; |
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} |
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ret = io_add_buffers(ctx, p, bl); |
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err: |
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if (ret < 0) |
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req_set_fail(req); |
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/* complete before unlock, IOPOLL may need the lock */ |
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io_req_set_res(req, ret, 0); |
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__io_req_complete(req, issue_flags); |
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io_ring_submit_unlock(ctx, issue_flags); |
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return IOU_ISSUE_SKIP_COMPLETE; |
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} |
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int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) |
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{ |
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struct io_uring_buf_ring *br; |
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struct io_uring_buf_reg reg; |
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struct io_buffer_list *bl, *free_bl = NULL; |
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struct page **pages; |
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int nr_pages; |
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if (copy_from_user(®, arg, sizeof(reg))) |
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return -EFAULT; |
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if (reg.pad || reg.resv[0] || reg.resv[1] || reg.resv[2]) |
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return -EINVAL; |
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if (!reg.ring_addr) |
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return -EFAULT; |
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if (reg.ring_addr & ~PAGE_MASK) |
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return -EINVAL; |
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if (!is_power_of_2(reg.ring_entries)) |
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return -EINVAL; |
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/* cannot disambiguate full vs empty due to head/tail size */ |
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if (reg.ring_entries >= 65536) |
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return -EINVAL; |
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if (unlikely(reg.bgid < BGID_ARRAY && !ctx->io_bl)) { |
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int ret = io_init_bl_list(ctx); |
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if (ret) |
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return ret; |
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} |
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bl = io_buffer_get_list(ctx, reg.bgid); |
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if (bl) { |
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/* if mapped buffer ring OR classic exists, don't allow */ |
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if (bl->buf_nr_pages || !list_empty(&bl->buf_list)) |
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return -EEXIST; |
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} else { |
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free_bl = bl = kzalloc(sizeof(*bl), GFP_KERNEL); |
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if (!bl) |
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return -ENOMEM; |
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} |
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pages = io_pin_pages(reg.ring_addr, |
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struct_size(br, bufs, reg.ring_entries), |
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&nr_pages); |
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if (IS_ERR(pages)) { |
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kfree(free_bl); |
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return PTR_ERR(pages); |
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} |
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br = page_address(pages[0]); |
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bl->buf_pages = pages; |
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bl->buf_nr_pages = nr_pages; |
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bl->nr_entries = reg.ring_entries; |
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bl->buf_ring = br; |
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bl->mask = reg.ring_entries - 1; |
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io_buffer_add_list(ctx, bl, reg.bgid); |
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return 0; |
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} |
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int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) |
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{ |
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struct io_uring_buf_reg reg; |
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struct io_buffer_list *bl; |
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|
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if (copy_from_user(®, arg, sizeof(reg))) |
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return -EFAULT; |
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if (reg.pad || reg.resv[0] || reg.resv[1] || reg.resv[2]) |
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return -EINVAL; |
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bl = io_buffer_get_list(ctx, reg.bgid); |
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if (!bl) |
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return -ENOENT; |
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if (!bl->buf_nr_pages) |
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return -EINVAL; |
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|
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__io_remove_buffers(ctx, bl, -1U); |
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if (bl->bgid >= BGID_ARRAY) { |
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xa_erase(&ctx->io_bl_xa, bl->bgid); |
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kfree(bl); |
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} |
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return 0; |
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}
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