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authorChristoph Hellwig <hch@lst.de>2020-05-20 17:58:12 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2020-05-20 12:11:26 -0400
commitf6dd975583bd8ce088400648fd9819e4691c8958 (patch)
tree73f60b95a258fc83e535781510a66288e2190a52 /fs/pipe.c
parent00c285d0d0fe4606d20fe88f1c824962475ba880 (diff)
downloadlinux-f6dd975583bd8ce088400648fd9819e4691c8958.tar.bz2
pipe: merge anon_pipe_buf*_ops
All the op vectors are exactly the same, they are just used to encode packet or nomerge behavior. There already is a flag for the packet behavior, so just add a new one to allow for merging. Inverting it vs the previous nomerge special casing actually allows for much nicer code. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/pipe.c')
-rw-r--r--fs/pipe.c45
1 files changed, 5 insertions, 40 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index 16fb72e9abf7..8e52b78b4042 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -231,7 +231,6 @@ void generic_pipe_buf_release(struct pipe_inode_info *pipe,
}
EXPORT_SYMBOL(generic_pipe_buf_release);
-/* New data written to a pipe may be appended to a buffer with this type. */
static const struct pipe_buf_operations anon_pipe_buf_ops = {
.confirm = generic_pipe_buf_confirm,
.release = anon_pipe_buf_release,
@@ -239,40 +238,6 @@ static const struct pipe_buf_operations anon_pipe_buf_ops = {
.get = generic_pipe_buf_get,
};
-static const struct pipe_buf_operations anon_pipe_buf_nomerge_ops = {
- .confirm = generic_pipe_buf_confirm,
- .release = anon_pipe_buf_release,
- .steal = anon_pipe_buf_steal,
- .get = generic_pipe_buf_get,
-};
-
-static const struct pipe_buf_operations packet_pipe_buf_ops = {
- .confirm = generic_pipe_buf_confirm,
- .release = anon_pipe_buf_release,
- .steal = anon_pipe_buf_steal,
- .get = generic_pipe_buf_get,
-};
-
-/**
- * pipe_buf_mark_unmergeable - mark a &struct pipe_buffer as unmergeable
- * @buf: the buffer to mark
- *
- * Description:
- * This function ensures that no future writes will be merged into the
- * given &struct pipe_buffer. This is necessary when multiple pipe buffers
- * share the same backing page.
- */
-void pipe_buf_mark_unmergeable(struct pipe_buffer *buf)
-{
- if (buf->ops == &anon_pipe_buf_ops)
- buf->ops = &anon_pipe_buf_nomerge_ops;
-}
-
-static bool pipe_buf_can_merge(struct pipe_buffer *buf)
-{
- return buf->ops == &anon_pipe_buf_ops;
-}
-
/* Done while waiting without holding the pipe lock - thus the READ_ONCE() */
static inline bool pipe_readable(const struct pipe_inode_info *pipe)
{
@@ -478,7 +443,8 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
struct pipe_buffer *buf = &pipe->bufs[(head - 1) & mask];
int offset = buf->offset + buf->len;
- if (pipe_buf_can_merge(buf) && offset + chars <= PAGE_SIZE) {
+ if ((buf->flags & PIPE_BUF_FLAG_CAN_MERGE) &&
+ offset + chars <= PAGE_SIZE) {
ret = pipe_buf_confirm(pipe, buf);
if (ret)
goto out;
@@ -541,11 +507,10 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
buf->ops = &anon_pipe_buf_ops;
buf->offset = 0;
buf->len = 0;
- buf->flags = 0;
- if (is_packetized(filp)) {
- buf->ops = &packet_pipe_buf_ops;
+ if (is_packetized(filp))
buf->flags = PIPE_BUF_FLAG_PACKET;
- }
+ else
+ buf->flags = PIPE_BUF_FLAG_CAN_MERGE;
pipe->tmp_page = NULL;
copied = copy_page_from_iter(page, 0, PAGE_SIZE, from);