1 files changed, 201 insertions, 109 deletions

diff --git a/net/sunrpc/socklib.c b/net/sunrpc/socklib.c
index 0a648c502fc3..d8d8842c7de5 100644
--- a/net/sunrpc/socklib.c
+++ b/net/sunrpc/socklib.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * linux/net/sunrpc/socklib.c
  *
@@ -13,134 +14,106 @@
 #include <linux/types.h>
 #include <linux/pagemap.h>
 #include <linux/udp.h>
+#include <linux/sunrpc/msg_prot.h>
+#include <linux/sunrpc/sched.h>
 #include <linux/sunrpc/xdr.h>
 #include <linux/export.h>
 
+#include "socklib.h"
 
-/**
- * xdr_skb_read_bits - copy some data bits from skb to internal buffer
- * @desc: sk_buff copy helper
- * @to: copy destination
- * @len: number of bytes to copy
- *
- * Possibly called several times to iterate over an sk_buff and copy
- * data out of it.
+/*
+ * Helper structure for copying from an sk_buff.
  */
-size_t xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
-{
-	if (len > desc->count)
-		len = desc->count;
-	if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
-		return 0;
-	desc->count -= len;
-	desc->offset += len;
-	return len;
-}
-EXPORT_SYMBOL_GPL(xdr_skb_read_bits);
+struct xdr_skb_reader {
+	struct sk_buff	*skb;
+	unsigned int	offset;
+	bool		need_checksum;
+	size_t		count;
+	__wsum		csum;
+};
 
 /**
- * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
+ * xdr_skb_read_bits - copy some data bits from skb to internal buffer
  * @desc: sk_buff copy helper
  * @to: copy destination
  * @len: number of bytes to copy
  *
- * Same as skb_read_bits, but calculate a checksum at the same time.
+ * Possibly called several times to iterate over an sk_buff and copy data out of
+ * it.
  */
-static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len)
+static size_t
+xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
 {
-	unsigned int pos;
-	__wsum csum2;
-
-	if (len > desc->count)
-		len = desc->count;
-	pos = desc->offset;
-	csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
-	desc->csum = csum_block_add(desc->csum, csum2, pos);
+	len = min(len, desc->count);
+
+	if (desc->need_checksum) {
+		__wsum csum;
+
+		csum = skb_copy_and_csum_bits(desc->skb, desc->offset, to, len);
+		desc->csum = csum_block_add(desc->csum, csum, desc->offset);
+	} else {
+		if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
+			return 0;
+	}
+
 	desc->count -= len;
 	desc->offset += len;
 	return len;
 }
 
-/**
- * xdr_partial_copy_from_skb - copy data out of an skb
- * @xdr: target XDR buffer
- * @base: starting offset
- * @desc: sk_buff copy helper
- * @copy_actor: virtual method for copying data
- *
- */
-ssize_t xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor)
+static ssize_t
+xdr_partial_copy_from_skb(struct xdr_buf *xdr, struct xdr_skb_reader *desc)
 {
-	struct page	**ppage = xdr->pages;
-	unsigned int	len, pglen = xdr->page_len;
-	ssize_t		copied = 0;
-	size_t		ret;
-
-	len = xdr->head[0].iov_len;
-	if (base < len) {
-		len -= base;
-		ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
-		copied += ret;
-		if (ret != len || !desc->count)
-			goto out;
-		base = 0;
-	} else
-		base -= len;
-
-	if (unlikely(pglen == 0))
-		goto copy_tail;
-	if (unlikely(base >= pglen)) {
-		base -= pglen;
-		goto copy_tail;
-	}
-	if (base || xdr->page_base) {
-		pglen -= base;
-		base += xdr->page_base;
-		ppage += base >> PAGE_CACHE_SHIFT;
-		base &= ~PAGE_CACHE_MASK;
-	}
-	do {
+	struct page **ppage = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
+	unsigned int poff = xdr->page_base & ~PAGE_MASK;
+	unsigned int pglen = xdr->page_len;
+	ssize_t copied = 0;
+	size_t ret;
+
+	if (xdr->head[0].iov_len == 0)
+		return 0;
+
+	ret = xdr_skb_read_bits(desc, xdr->head[0].iov_base,
+				xdr->head[0].iov_len);
+	if (ret != xdr->head[0].iov_len || !desc->count)
+		return ret;
+	copied += ret;
+
+	while (pglen) {
+		unsigned int len = min(PAGE_SIZE - poff, pglen);
 		char *kaddr;
 
 		/* ACL likes to be lazy in allocating pages - ACLs
 		 * are small by default but can get huge. */
-		if (unlikely(*ppage == NULL)) {
-			*ppage = alloc_page(GFP_ATOMIC);
+		if ((xdr->flags & XDRBUF_SPARSE_PAGES) && *ppage == NULL) {
+			*ppage = alloc_page(GFP_NOWAIT);
 			if (unlikely(*ppage == NULL)) {
 				if (copied == 0)
-					copied = -ENOMEM;
-				goto out;
+					return -ENOMEM;
+				return copied;
 			}
 		}
 
-		len = PAGE_CACHE_SIZE;
 		kaddr = kmap_atomic(*ppage);
-		if (base) {
-			len -= base;
-			if (pglen < len)
-				len = pglen;
-			ret = copy_actor(desc, kaddr + base, len);
-			base = 0;
-		} else {
-			if (pglen < len)
-				len = pglen;
-			ret = copy_actor(desc, kaddr, len);
-		}
+		ret = xdr_skb_read_bits(desc, kaddr + poff, len);
 		flush_dcache_page(*ppage);
 		kunmap_atomic(kaddr);
+
 		copied += ret;
 		if (ret != len || !desc->count)
-			goto out;
+			return copied;
 		ppage++;
-	} while ((pglen -= len) != 0);
-copy_tail:
-	len = xdr->tail[0].iov_len;
-	if (base < len)
-		copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
-out:
+		pglen -= len;
+		poff = 0;
+	}
+
+	if (xdr->tail[0].iov_len) {
+		copied += xdr_skb_read_bits(desc, xdr->tail[0].iov_base,
+					xdr->tail[0].iov_len);
+	}
+
 	return copied;
 }
-EXPORT_SYMBOL_GPL(xdr_partial_copy_from_skb);
 
 /**
  * csum_partial_copy_to_xdr - checksum and copy data
@@ -152,17 +125,22 @@ EXPORT_SYMBOL_GPL(xdr_partial_copy_from_skb);
  */
 int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
 {
-	struct xdr_skb_reader	desc;
-
-	desc.skb = skb;
-	desc.offset = sizeof(struct udphdr);
-	desc.count = skb->len - desc.offset;
+	struct xdr_skb_reader desc = {
+		.skb		= skb,
+		.count		= skb->len - desc.offset,
+	};
 
-	if (skb_csum_unnecessary(skb))
-		goto no_checksum;
+	if (skb_csum_unnecessary(skb)) {
+		if (xdr_partial_copy_from_skb(xdr, &desc) < 0)
+			return -1;
+		if (desc.count)
+			return -1;
+		return 0;
+	}
 
+	desc.need_checksum = true;
 	desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
-	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
+	if (xdr_partial_copy_from_skb(xdr, &desc) < 0)
 		return -1;
 	if (desc.offset != skb->len) {
 		__wsum csum2;
@@ -173,14 +151,128 @@ int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
 		return -1;
 	if (csum_fold(desc.csum))
 		return -1;
-	if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
-		netdev_rx_csum_fault(skb->dev);
-	return 0;
-no_checksum:
-	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
-		return -1;
-	if (desc.count)
-		return -1;
+	if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
+	    !skb->csum_complete_sw)
+		netdev_rx_csum_fault(skb->dev, skb);
 	return 0;
 }
-EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);
+
+static inline int xprt_sendmsg(struct socket *sock, struct msghdr *msg,
+			       size_t seek)
+{
+	if (seek)
+		iov_iter_advance(&msg->msg_iter, seek);
+	return sock_sendmsg(sock, msg);
+}
+
+static int xprt_send_kvec(struct socket *sock, struct msghdr *msg,
+			  struct kvec *vec, size_t seek)
+{
+	iov_iter_kvec(&msg->msg_iter, ITER_SOURCE, vec, 1, vec->iov_len);
+	return xprt_sendmsg(sock, msg, seek);
+}
+
+static int xprt_send_pagedata(struct socket *sock, struct msghdr *msg,
+			      struct xdr_buf *xdr, size_t base)
+{
+	iov_iter_bvec(&msg->msg_iter, ITER_SOURCE, xdr->bvec, xdr_buf_pagecount(xdr),
+		      xdr->page_len + xdr->page_base);
+	return xprt_sendmsg(sock, msg, base + xdr->page_base);
+}
+
+/* Common case:
+ *  - stream transport
+ *  - sending from byte 0 of the message
+ *  - the message is wholly contained in @xdr's head iovec
+ */
+static int xprt_send_rm_and_kvec(struct socket *sock, struct msghdr *msg,
+				 rpc_fraghdr marker, struct kvec *vec,
+				 size_t base)
+{
+	struct kvec iov[2] = {
+		[0] = {
+			.iov_base	= &marker,
+			.iov_len	= sizeof(marker)
+		},
+		[1] = *vec,
+	};
+	size_t len = iov[0].iov_len + iov[1].iov_len;
+
+	iov_iter_kvec(&msg->msg_iter, ITER_SOURCE, iov, 2, len);
+	return xprt_sendmsg(sock, msg, base);
+}
+
+/**
+ * xprt_sock_sendmsg - write an xdr_buf directly to a socket
+ * @sock: open socket to send on
+ * @msg: socket message metadata
+ * @xdr: xdr_buf containing this request
+ * @base: starting position in the buffer
+ * @marker: stream record marker field
+ * @sent_p: return the total number of bytes successfully queued for sending
+ *
+ * Return values:
+ *   On success, returns zero and fills in @sent_p.
+ *   %-ENOTSOCK if  @sock is not a struct socket.
+ */
+int xprt_sock_sendmsg(struct socket *sock, struct msghdr *msg,
+		      struct xdr_buf *xdr, unsigned int base,
+		      rpc_fraghdr marker, unsigned int *sent_p)
+{
+	unsigned int rmsize = marker ? sizeof(marker) : 0;
+	unsigned int remainder = rmsize + xdr->len - base;
+	unsigned int want;
+	int err = 0;
+
+	*sent_p = 0;
+
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	msg->msg_flags |= MSG_MORE;
+	want = xdr->head[0].iov_len + rmsize;
+	if (base < want) {
+		unsigned int len = want - base;
+
+		remainder -= len;
+		if (remainder == 0)
+			msg->msg_flags &= ~MSG_MORE;
+		if (rmsize)
+			err = xprt_send_rm_and_kvec(sock, msg, marker,
+						    &xdr->head[0], base);
+		else
+			err = xprt_send_kvec(sock, msg, &xdr->head[0], base);
+		if (remainder == 0 || err != len)
+			goto out;
+		*sent_p += err;
+		base = 0;
+	} else {
+		base -= want;
+	}
+
+	if (base < xdr->page_len) {
+		unsigned int len = xdr->page_len - base;
+
+		remainder -= len;
+		if (remainder == 0)
+			msg->msg_flags &= ~MSG_MORE;
+		err = xprt_send_pagedata(sock, msg, xdr, base);
+		if (remainder == 0 || err != len)
+			goto out;
+		*sent_p += err;
+		base = 0;
+	} else {
+		base -= xdr->page_len;
+	}
+
+	if (base >= xdr->tail[0].iov_len)
+		return 0;
+	msg->msg_flags &= ~MSG_MORE;
+	err = xprt_send_kvec(sock, msg, &xdr->tail[0], base);
+out:
+	if (err > 0) {
+		*sent_p += err;
+		err = 0;
+	}
+	return err;
+}