Merge branch 'splice-net-switch-over-users-of-sendpage-and-remove-it'

David Howells says:

====================
splice, net: Switch over users of sendpage() and remove it

Here's the final set of patches towards the removal of sendpage.  All the
drivers that use sendpage() get switched over to using sendmsg() with
MSG_SPLICE_PAGES.

The following changes are made:

 (1) Make the protocol drivers behave according to MSG_MORE, not
     MSG_SENDPAGE_NOTLAST.  The latter is restricted to turning on MSG_MORE
     in the sendpage() wrappers.

 (2) Fix ocfs2 to allocate its global protocol buffers with folio_alloc()
     rather than kzalloc() so as not to invoke the !sendpage_ok warning in
     skb_splice_from_iter().

 (3) Make ceph/rds, skb_send_sock, dlm, nvme, smc, ocfs2, drbd and iscsi
     use sendmsg(), not sendpage and make them specify MSG_MORE instead of
     MSG_SENDPAGE_NOTLAST.

 (4) Kill off sendpage and clean up MSG_SENDPAGE_NOTLAST.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=51c78a4d532efe9543a4df019ff405f05c6157f6 # part 1
Link: https://lore.kernel.org/r/20230616161301.622169-1-dhowells@redhat.com/ # v1
Link: https://lore.kernel.org/r/20230617121146.716077-1-dhowells@redhat.com/ # v2
Link: https://lore.kernel.org/r/20230620145338.1300897-1-dhowells@redhat.com/ # v3
====================

Link: https://lore.kernel.org/r/20230623225513.2732256-1-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

Documentation/bpf/map_sockmap.rst

@@ -240,11 +240,11 @@ offsets into ``msg``, respectively.
 If a program of type ``BPF_PROG_TYPE_SK_MSG`` is run on a ``msg`` it can only
 parse data that the (``data``, ``data_end``) pointers have already consumed.
 For ``sendmsg()`` hooks this is likely the first scatterlist element. But for
-calls relying on the ``sendpage`` handler (e.g., ``sendfile()``) this will be
-the range (**0**, **0**) because the data is shared with user space and by
-default the objective is to avoid allowing user space to modify data while (or
-after) BPF verdict is being decided. This helper can be used to pull in data
-and to set the start and end pointers to given values. Data will be copied if
+calls relying on MSG_SPLICE_PAGES (e.g., ``sendfile()``) this will be the
+range (**0**, **0**) because the data is shared with user space and by default
+the objective is to avoid allowing user space to modify data while (or after)
+BPF verdict is being decided. This helper can be used to pull in data and to
+set the start and end pointers to given values. Data will be copied if
 necessary (i.e., if data was not linear and if start and end pointers do not
 point to the same chunk).
 

Documentation/filesystems/locking.rst

@@ -521,8 +521,6 @@ prototypes::
 	int (*fsync) (struct file *, loff_t start, loff_t end, int datasync);
 	int (*fasync) (int, struct file *, int);
 	int (*lock) (struct file *, int, struct file_lock *);
-	ssize_t (*sendpage) (struct file *, struct page *, int, size_t,
-			loff_t *, int);
 	unsigned long (*get_unmapped_area)(struct file *, unsigned long,
 			unsigned long, unsigned long, unsigned long);
 	int (*check_flags)(int);

Documentation/filesystems/vfs.rst

@@ -1086,7 +1086,6 @@ This describes how the VFS can manipulate an open file.  As of kernel
 		int (*fsync) (struct file *, loff_t, loff_t, int datasync);
 		int (*fasync) (int, struct file *, int);
 		int (*lock) (struct file *, int, struct file_lock *);
-		ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
 		unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
 		int (*check_flags)(int);
 		int (*flock) (struct file *, int, struct file_lock *);

Documentation/networking/scaling.rst

@@ -269,8 +269,8 @@ a single application thread handles flows with many different flow hashes.
 rps_sock_flow_table is a global flow table that contains the *desired* CPU
 for flows: the CPU that is currently processing the flow in userspace.
 Each table value is a CPU index that is updated during calls to recvmsg
-and sendmsg (specifically, inet_recvmsg(), inet_sendmsg(), inet_sendpage()
-and tcp_splice_read()).
+and sendmsg (specifically, inet_recvmsg(), inet_sendmsg() and
+tcp_splice_read()).
 
 When the scheduler moves a thread to a new CPU while it has outstanding
 receive packets on the old CPU, packets may arrive out of order. To

crypto/af_alg.c

@@ -482,7 +482,6 @@ static const struct proto_ops alg_proto_ops = {
 	.listen		=	sock_no_listen,
 	.shutdown	=	sock_no_shutdown,
 	.mmap		=	sock_no_mmap,
-	.sendpage	=	sock_no_sendpage,
 	.sendmsg	=	sock_no_sendmsg,
 	.recvmsg	=	sock_no_recvmsg,
 
@@ -1106,33 +1105,6 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 }
 EXPORT_SYMBOL_GPL(af_alg_sendmsg);
 
-/**
- * af_alg_sendpage - sendpage system call handler
- * @sock: socket of connection to user space to write to
- * @page: data to send
- * @offset: offset into page to begin sending
- * @size: length of data
- * @flags: message send/receive flags
- *
- * This is a generic implementation of sendpage to fill ctx->tsgl_list.
- */
-ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
-			int offset, size_t size, int flags)
-{
-	struct bio_vec bvec;
-	struct msghdr msg = {
-		.msg_flags = flags | MSG_SPLICE_PAGES,
-	};
-
-	if (flags & MSG_SENDPAGE_NOTLAST)
-		msg.msg_flags |= MSG_MORE;
-
-	bvec_set_page(&bvec, page, size, offset);
-	iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size);
-	return sock_sendmsg(sock, &msg);
-}
-EXPORT_SYMBOL_GPL(af_alg_sendpage);
-
 /**
  * af_alg_free_resources - release resources required for crypto request
  * @areq: Request holding the TX and RX SGL

crypto/algif_aead.c

@@ -9,10 +9,10 @@
  * The following concept of the memory management is used:
  *
  * The kernel maintains two SGLs, the TX SGL and the RX SGL. The TX SGL is
- * filled by user space with the data submitted via sendpage. Filling up
- * the TX SGL does not cause a crypto operation -- the data will only be
- * tracked by the kernel. Upon receipt of one recvmsg call, the caller must
- * provide a buffer which is tracked with the RX SGL.
+ * filled by user space with the data submitted via sendmsg (maybe with
+ * MSG_SPLICE_PAGES).  Filling up the TX SGL does not cause a crypto operation
+ * -- the data will only be tracked by the kernel. Upon receipt of one recvmsg
+ * call, the caller must provide a buffer which is tracked with the RX SGL.
  *
  * During the processing of the recvmsg operation, the cipher request is
  * allocated and prepared. As part of the recvmsg operation, the processed
@@ -370,7 +370,6 @@ static struct proto_ops algif_aead_ops = {
 
 	.release	=	af_alg_release,
 	.sendmsg	=	aead_sendmsg,
-	.sendpage	=	af_alg_sendpage,
 	.recvmsg	=	aead_recvmsg,
 	.poll		=	af_alg_poll,
 };
@@ -422,18 +421,6 @@ static int aead_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
 	return aead_sendmsg(sock, msg, size);
 }
 
-static ssize_t aead_sendpage_nokey(struct socket *sock, struct page *page,
-				       int offset, size_t size, int flags)
-{
-	int err;
-
-	err = aead_check_key(sock);
-	if (err)
-		return err;
-
-	return af_alg_sendpage(sock, page, offset, size, flags);
-}
-
 static int aead_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
 				  size_t ignored, int flags)
 {
@@ -461,7 +448,6 @@ static struct proto_ops algif_aead_ops_nokey = {
 
 	.release	=	af_alg_release,
 	.sendmsg	=	aead_sendmsg_nokey,
-	.sendpage	=	aead_sendpage_nokey,
 	.recvmsg	=	aead_recvmsg_nokey,
 	.poll		=	af_alg_poll,
 };

crypto/algif_rng.c

@@ -174,7 +174,6 @@ static struct proto_ops algif_rng_ops = {
 	.bind		=	sock_no_bind,
 	.accept		=	sock_no_accept,
 	.sendmsg	=	sock_no_sendmsg,
-	.sendpage	=	sock_no_sendpage,
 
 	.release	=	af_alg_release,
 	.recvmsg	=	rng_recvmsg,
@@ -192,7 +191,6 @@ static struct proto_ops __maybe_unused algif_rng_test_ops = {
 	.mmap		=	sock_no_mmap,
 	.bind		=	sock_no_bind,
 	.accept		=	sock_no_accept,
-	.sendpage	=	sock_no_sendpage,
 
 	.release	=	af_alg_release,
 	.recvmsg	=	rng_test_recvmsg,

crypto/algif_skcipher.c

@@ -194,7 +194,6 @@ static struct proto_ops algif_skcipher_ops = {
 
 	.release	=	af_alg_release,
 	.sendmsg	=	skcipher_sendmsg,
-	.sendpage	=	af_alg_sendpage,
 	.recvmsg	=	skcipher_recvmsg,
 	.poll		=	af_alg_poll,
 };
@@ -246,18 +245,6 @@ static int skcipher_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
 	return skcipher_sendmsg(sock, msg, size);
 }
 
-static ssize_t skcipher_sendpage_nokey(struct socket *sock, struct page *page,
-				       int offset, size_t size, int flags)
-{
-	int err;
-
-	err = skcipher_check_key(sock);
-	if (err)
-		return err;
-
-	return af_alg_sendpage(sock, page, offset, size, flags);
-}
-
 static int skcipher_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
 				  size_t ignored, int flags)
 {
@@ -285,7 +272,6 @@ static struct proto_ops algif_skcipher_ops_nokey = {
 
 	.release	=	af_alg_release,
 	.sendmsg	=	skcipher_sendmsg_nokey,
-	.sendpage	=	skcipher_sendpage_nokey,
 	.recvmsg	=	skcipher_recvmsg_nokey,
 	.poll		=	af_alg_poll,
 };

drivers/block/drbd/drbd_main.c

@@ -1540,6 +1540,8 @@ static int _drbd_send_page(struct drbd_peer_device *peer_device, struct page *pa
 		    int offset, size_t size, unsigned msg_flags)
 {
 	struct socket *socket = peer_device->connection->data.socket;
+	struct msghdr msg = { .msg_flags = msg_flags, };
+	struct bio_vec bvec;
 	int len = size;
 	int err = -EIO;
 
@@ -1549,15 +1551,17 @@ static int _drbd_send_page(struct drbd_peer_device *peer_device, struct page *pa
 	 * put_page(); and would cause either a VM_BUG directly, or
 	 * __page_cache_release a page that would actually still be referenced
 	 * by someone, leading to some obscure delayed Oops somewhere else. */
-	if (drbd_disable_sendpage || !sendpage_ok(page))
-		return _drbd_no_send_page(peer_device, page, offset, size, msg_flags);
+	if (!drbd_disable_sendpage && sendpage_ok(page))
+		msg.msg_flags |= MSG_NOSIGNAL | MSG_SPLICE_PAGES;
 
-	msg_flags |= MSG_NOSIGNAL;
 	drbd_update_congested(peer_device->connection);
 	do {
 		int sent;
 
-		sent = socket->ops->sendpage(socket, page, offset, len, msg_flags);
+		bvec_set_page(&bvec, page, offset, len);
+		iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, len);
+
+		sent = sock_sendmsg(socket, &msg);
 		if (sent <= 0) {
 			if (sent == -EAGAIN) {
 				if (we_should_drop_the_connection(peer_device->connection, socket))

drivers/infiniband/sw/siw/siw_qp_tx.c

@@ -325,8 +325,7 @@ static int siw_tcp_sendpages(struct socket *s, struct page **page, int offset,
 {
 	struct bio_vec bvec;
 	struct msghdr msg = {
-		.msg_flags = (MSG_MORE | MSG_DONTWAIT | MSG_SENDPAGE_NOTLAST |
-			      MSG_SPLICE_PAGES),
+		.msg_flags = (MSG_MORE | MSG_DONTWAIT | MSG_SPLICE_PAGES),
 	};
 	struct sock *sk = s->sk;
 	int i = 0, rv = 0, sent = 0;
@@ -335,7 +334,7 @@ static int siw_tcp_sendpages(struct socket *s, struct page **page, int offset,
 		size_t bytes = min_t(size_t, PAGE_SIZE - offset, size);
 
 		if (size + offset <= PAGE_SIZE)
-			msg.msg_flags &= ~MSG_SENDPAGE_NOTLAST;
+			msg.msg_flags &= ~MSG_MORE;
 
 		tcp_rate_check_app_limited(sk);
 		bvec_set_page(&bvec, page[i], bytes, offset);