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329 lines
7.9 KiB
329 lines
7.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* linux/net/sunrpc/socklib.c |
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* |
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* Common socket helper routines for RPC client and server |
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* |
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* Copyright (C) 1995, 1996 Olaf Kirch <[email protected]> |
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*/ |
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#include <linux/compiler.h> |
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#include <linux/netdevice.h> |
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#include <linux/gfp.h> |
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#include <linux/skbuff.h> |
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#include <linux/types.h> |
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#include <linux/pagemap.h> |
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#include <linux/udp.h> |
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#include <linux/sunrpc/msg_prot.h> |
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#include <linux/sunrpc/xdr.h> |
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#include <linux/export.h> |
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#include "socklib.h" |
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/* |
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* Helper structure for copying from an sk_buff. |
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*/ |
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struct xdr_skb_reader { |
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struct sk_buff *skb; |
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unsigned int offset; |
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size_t count; |
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__wsum csum; |
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}; |
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typedef size_t (*xdr_skb_read_actor)(struct xdr_skb_reader *desc, void *to, |
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size_t len); |
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/** |
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* xdr_skb_read_bits - copy some data bits from skb to internal buffer |
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* @desc: sk_buff copy helper |
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* @to: copy destination |
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* @len: number of bytes to copy |
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* |
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* Possibly called several times to iterate over an sk_buff and copy |
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* data out of it. |
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*/ |
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static size_t |
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xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len) |
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{ |
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if (len > desc->count) |
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len = desc->count; |
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if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len))) |
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return 0; |
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desc->count -= len; |
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desc->offset += len; |
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return len; |
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} |
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/** |
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* xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer |
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* @desc: sk_buff copy helper |
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* @to: copy destination |
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* @len: number of bytes to copy |
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* |
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* Same as skb_read_bits, but calculate a checksum at the same time. |
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*/ |
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static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len) |
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{ |
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unsigned int pos; |
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__wsum csum2; |
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if (len > desc->count) |
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len = desc->count; |
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pos = desc->offset; |
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csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len); |
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desc->csum = csum_block_add(desc->csum, csum2, pos); |
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desc->count -= len; |
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desc->offset += len; |
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return len; |
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} |
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/** |
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* xdr_partial_copy_from_skb - copy data out of an skb |
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* @xdr: target XDR buffer |
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* @base: starting offset |
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* @desc: sk_buff copy helper |
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* @copy_actor: virtual method for copying data |
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* |
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*/ |
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static ssize_t |
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xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor) |
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{ |
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struct page **ppage = xdr->pages; |
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unsigned int len, pglen = xdr->page_len; |
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ssize_t copied = 0; |
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size_t ret; |
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len = xdr->head[0].iov_len; |
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if (base < len) { |
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len -= base; |
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ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len); |
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copied += ret; |
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if (ret != len || !desc->count) |
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goto out; |
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base = 0; |
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} else |
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base -= len; |
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if (unlikely(pglen == 0)) |
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goto copy_tail; |
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if (unlikely(base >= pglen)) { |
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base -= pglen; |
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goto copy_tail; |
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} |
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if (base || xdr->page_base) { |
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pglen -= base; |
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base += xdr->page_base; |
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ppage += base >> PAGE_SHIFT; |
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base &= ~PAGE_MASK; |
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} |
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do { |
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char *kaddr; |
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/* ACL likes to be lazy in allocating pages - ACLs |
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* are small by default but can get huge. */ |
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if ((xdr->flags & XDRBUF_SPARSE_PAGES) && *ppage == NULL) { |
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*ppage = alloc_page(GFP_NOWAIT | __GFP_NOWARN); |
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if (unlikely(*ppage == NULL)) { |
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if (copied == 0) |
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copied = -ENOMEM; |
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goto out; |
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} |
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} |
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len = PAGE_SIZE; |
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kaddr = kmap_atomic(*ppage); |
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if (base) { |
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len -= base; |
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if (pglen < len) |
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len = pglen; |
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ret = copy_actor(desc, kaddr + base, len); |
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base = 0; |
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} else { |
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if (pglen < len) |
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len = pglen; |
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ret = copy_actor(desc, kaddr, len); |
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} |
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flush_dcache_page(*ppage); |
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kunmap_atomic(kaddr); |
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copied += ret; |
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if (ret != len || !desc->count) |
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goto out; |
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ppage++; |
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} while ((pglen -= len) != 0); |
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copy_tail: |
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len = xdr->tail[0].iov_len; |
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if (base < len) |
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copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base); |
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out: |
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return copied; |
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} |
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/** |
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* csum_partial_copy_to_xdr - checksum and copy data |
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* @xdr: target XDR buffer |
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* @skb: source skb |
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* |
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* We have set things up such that we perform the checksum of the UDP |
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* packet in parallel with the copies into the RPC client iovec. -DaveM |
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*/ |
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int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb) |
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{ |
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struct xdr_skb_reader desc; |
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desc.skb = skb; |
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desc.offset = 0; |
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desc.count = skb->len - desc.offset; |
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if (skb_csum_unnecessary(skb)) |
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goto no_checksum; |
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desc.csum = csum_partial(skb->data, desc.offset, skb->csum); |
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if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0) |
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return -1; |
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if (desc.offset != skb->len) { |
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__wsum csum2; |
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csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0); |
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desc.csum = csum_block_add(desc.csum, csum2, desc.offset); |
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} |
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if (desc.count) |
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return -1; |
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if (csum_fold(desc.csum)) |
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return -1; |
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if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && |
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!skb->csum_complete_sw) |
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netdev_rx_csum_fault(skb->dev, skb); |
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return 0; |
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no_checksum: |
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if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0) |
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return -1; |
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if (desc.count) |
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return -1; |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr); |
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static inline int xprt_sendmsg(struct socket *sock, struct msghdr *msg, |
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size_t seek) |
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{ |
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if (seek) |
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iov_iter_advance(&msg->msg_iter, seek); |
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return sock_sendmsg(sock, msg); |
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} |
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static int xprt_send_kvec(struct socket *sock, struct msghdr *msg, |
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struct kvec *vec, size_t seek) |
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{ |
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iov_iter_kvec(&msg->msg_iter, WRITE, vec, 1, vec->iov_len); |
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return xprt_sendmsg(sock, msg, seek); |
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} |
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static int xprt_send_pagedata(struct socket *sock, struct msghdr *msg, |
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struct xdr_buf *xdr, size_t base) |
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{ |
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int err; |
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err = xdr_alloc_bvec(xdr, GFP_KERNEL); |
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if (err < 0) |
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return err; |
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iov_iter_bvec(&msg->msg_iter, WRITE, xdr->bvec, xdr_buf_pagecount(xdr), |
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xdr->page_len + xdr->page_base); |
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return xprt_sendmsg(sock, msg, base + xdr->page_base); |
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} |
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/* Common case: |
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* - stream transport |
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* - sending from byte 0 of the message |
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* - the message is wholly contained in @xdr's head iovec |
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*/ |
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static int xprt_send_rm_and_kvec(struct socket *sock, struct msghdr *msg, |
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rpc_fraghdr marker, struct kvec *vec, |
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size_t base) |
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{ |
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struct kvec iov[2] = { |
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[0] = { |
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.iov_base = &marker, |
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.iov_len = sizeof(marker) |
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}, |
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[1] = *vec, |
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}; |
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size_t len = iov[0].iov_len + iov[1].iov_len; |
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iov_iter_kvec(&msg->msg_iter, WRITE, iov, 2, len); |
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return xprt_sendmsg(sock, msg, base); |
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} |
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/** |
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* xprt_sock_sendmsg - write an xdr_buf directly to a socket |
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* @sock: open socket to send on |
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* @msg: socket message metadata |
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* @xdr: xdr_buf containing this request |
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* @base: starting position in the buffer |
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* @marker: stream record marker field |
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* @sent_p: return the total number of bytes successfully queued for sending |
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* |
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* Return values: |
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* On success, returns zero and fills in @sent_p. |
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* %-ENOTSOCK if @sock is not a struct socket. |
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*/ |
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int xprt_sock_sendmsg(struct socket *sock, struct msghdr *msg, |
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struct xdr_buf *xdr, unsigned int base, |
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rpc_fraghdr marker, unsigned int *sent_p) |
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{ |
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unsigned int rmsize = marker ? sizeof(marker) : 0; |
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unsigned int remainder = rmsize + xdr->len - base; |
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unsigned int want; |
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int err = 0; |
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*sent_p = 0; |
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if (unlikely(!sock)) |
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return -ENOTSOCK; |
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msg->msg_flags |= MSG_MORE; |
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want = xdr->head[0].iov_len + rmsize; |
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if (base < want) { |
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unsigned int len = want - base; |
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remainder -= len; |
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if (remainder == 0) |
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msg->msg_flags &= ~MSG_MORE; |
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if (rmsize) |
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err = xprt_send_rm_and_kvec(sock, msg, marker, |
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&xdr->head[0], base); |
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else |
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err = xprt_send_kvec(sock, msg, &xdr->head[0], base); |
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if (remainder == 0 || err != len) |
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goto out; |
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*sent_p += err; |
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base = 0; |
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} else { |
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base -= want; |
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} |
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if (base < xdr->page_len) { |
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unsigned int len = xdr->page_len - base; |
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remainder -= len; |
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if (remainder == 0) |
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msg->msg_flags &= ~MSG_MORE; |
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err = xprt_send_pagedata(sock, msg, xdr, base); |
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if (remainder == 0 || err != len) |
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goto out; |
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*sent_p += err; |
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base = 0; |
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} else { |
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base -= xdr->page_len; |
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} |
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if (base >= xdr->tail[0].iov_len) |
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return 0; |
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msg->msg_flags &= ~MSG_MORE; |
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err = xprt_send_kvec(sock, msg, &xdr->tail[0], base); |
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out: |
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if (err > 0) { |
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*sent_p += err; |
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err = 0; |
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} |
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return err; |
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}
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