[PATCH 2/2] pipe: remove ->can_merge from pipe_buf_operations

[Jann Horn]

My last commit "splice: don't merge into linked buffers" made the
"can_merge" field in struct pipe_buf_operations redundant: Whether a buffer
is mergeable is now a property of the buffer, not of the operations struct.
Get rid of it.

Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
---
 fs/pipe.c                 | 4 +---
 fs/splice.c               | 4 ----
 include/linux/pipe_fs_i.h | 7 -------
 kernel/relay.c            | 1 -
 kernel/trace/trace.c      | 2 --
 net/smc/smc_rx.c          | 1 -
 6 files changed, 1 insertion(+), 18 deletions(-)

diff --git a/fs/pipe.c b/fs/pipe.c
index 4e2eee77f855..b1ad3271c175 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -227,7 +227,6 @@ void generic_pipe_buf_release(struct pipe_inode_info *pipe,
 EXPORT_SYMBOL(generic_pipe_buf_release);
 
 static const struct pipe_buf_operations anon_pipe_buf_ops = {
-	.can_merge = 1,
 	.confirm = generic_pipe_buf_confirm,
 	.release = anon_pipe_buf_release,
 	.steal = anon_pipe_buf_steal,
@@ -235,7 +234,6 @@ static const struct pipe_buf_operations anon_pipe_buf_ops = {
 };
 
 static const struct pipe_buf_operations packet_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = anon_pipe_buf_release,
 	.steal = anon_pipe_buf_steal,
@@ -379,7 +377,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 		struct pipe_buffer *buf = pipe->bufs + lastbuf;
 		int offset = buf->offset + buf->len;
 
-		if (buf->ops->can_merge && offset + chars <= PAGE_SIZE &&
+		if (offset + chars <= PAGE_SIZE &&
 		    (buf->flags & PIPE_BUF_FLAG_MAYMERGE)) {
 			ret = pipe_buf_confirm(pipe, buf);
 			if (ret)
diff --git a/fs/splice.c b/fs/splice.c
index 111977c80dfd..fb7412b2eadb 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -138,7 +138,6 @@ static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe,
 }
 
 const struct pipe_buf_operations page_cache_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = page_cache_pipe_buf_confirm,
 	.release = page_cache_pipe_buf_release,
 	.steal = page_cache_pipe_buf_steal,
@@ -156,7 +155,6 @@ static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
 }
 
 static const struct pipe_buf_operations user_page_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = page_cache_pipe_buf_release,
 	.steal = user_page_pipe_buf_steal,
@@ -326,7 +324,6 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
 EXPORT_SYMBOL(generic_file_splice_read);
 
 const struct pipe_buf_operations default_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = generic_pipe_buf_release,
 	.steal = generic_pipe_buf_steal,
@@ -341,7 +338,6 @@ static int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe,
 
 /* Pipe buffer operations for a socket and similar. */
 const struct pipe_buf_operations nosteal_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = generic_pipe_buf_release,
 	.steal = generic_pipe_buf_nosteal,
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 8893711f9171..03d3529c7654 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -81,13 +81,6 @@ struct pipe_inode_info {
  * in fs/pipe.c for the pipe and generic variants of these hooks.
  */
 struct pipe_buf_operations {
-	/*
-	 * This is set to 1, if the generic pipe read/write may coalesce
-	 * data into an existing buffer. If this is set to 0, a new pipe
-	 * page segment is always used for new data.
-	 */
-	int can_merge;
-
 	/*
 	 * ->confirm() verifies that the data in the pipe buffer is there
 	 * and that the contents are good. If the pages in the pipe belong
diff --git a/kernel/relay.c b/kernel/relay.c
index 04f248644e06..db3e419c25a6 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -1175,7 +1175,6 @@ static void relay_pipe_buf_release(struct pipe_inode_info *pipe,
 }
 
 static const struct pipe_buf_operations relay_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = relay_pipe_buf_release,
 	.steal = generic_pipe_buf_steal,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index bf6f1d70484d..820eff45e907 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5803,7 +5803,6 @@ static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
 }
 
 static const struct pipe_buf_operations tracing_pipe_buf_ops = {
-	.can_merge		= 0,
 	.confirm		= generic_pipe_buf_confirm,
 	.release		= generic_pipe_buf_release,
 	.steal			= generic_pipe_buf_steal,
@@ -6823,7 +6822,6 @@ static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
 
 /* Pipe buffer operations for a buffer. */
 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
-	.can_merge		= 0,
 	.confirm		= generic_pipe_buf_confirm,
 	.release		= buffer_pipe_buf_release,
 	.steal			= generic_pipe_buf_steal,
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index bbcf0fe4ae10..413a6abf227e 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -136,7 +136,6 @@ static int smc_rx_pipe_buf_nosteal(struct pipe_inode_info *pipe,
 }
 
 static const struct pipe_buf_operations smc_pipe_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = smc_rx_pipe_buf_release,
 	.steal = smc_rx_pipe_buf_nosteal,
-- 
2.19.0.605.g01d371f741-goog