[PATCH v2 3/4] fs/pipe: Use pipe_buf() helper to retrieve pipe buffer

K Prateek Nayak
2025-03-07T05:30:37Z

Use pipe_buf() helper to retrieve the pipe buffer throughout the file
replacing the open-coded the logic.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
---
Changelog:

RFC v1..v2:

o New patch.
---
fs/pipe.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/fs/pipe.c b/fs/pipe.c
index 88e81f84e3ea..4d6ca0f892b1 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -274,7 +274,6 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
/* Read ->head with a barrier vs post_one_notification() */
unsigned int head = smp_load_acquire(&pipe->head);
unsigned int tail = pipe->tail;
- unsigned int mask = pipe->ring_size - 1;

#ifdef CONFIG_WATCH_QUEUE
if (pipe->note_loss) {
@@ -301,7 +300,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
#endif

if (!pipe_empty(head, tail)) {
- struct pipe_buffer *buf = &pipe->bufs[tail & mask];
+ struct pipe_buffer *buf = pipe_buf(pipe, tail);
size_t chars = buf->len;
size_t written;
int error;
@@ -471,8 +470,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
was_empty = pipe_empty(head, pipe->tail);
chars = total_len & (PAGE_SIZE-1);
if (chars && !was_empty) {
- unsigned int mask = pipe->ring_size - 1;
- struct pipe_buffer *buf = &pipe->bufs[(head - 1) & mask];
+ struct pipe_buffer *buf = pipe_buf(pipe, head - 1);
int offset = buf->offset + buf->len;

if ((buf->flags & PIPE_BUF_FLAG_CAN_MERGE) &&
@@ -503,7 +501,6 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)

head = pipe->head;
if (!pipe_full(head, pipe->tail, pipe->max_usage)) {
- unsigned int mask = pipe->ring_size - 1;
struct pipe_buffer *buf;
struct page *page = pipe->tmp_page;
int copied;
@@ -525,7 +522,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
pipe->head = head + 1;

/* Insert it into the buffer array */
- buf = &pipe->bufs[head & mask];
+ buf = pipe_buf(pipe, head);
buf->page = page;
buf->ops = &anon_pipe_buf_ops;
buf->offset = 0;
--
2.43.0