Unverified Commit 3732d8f1 authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge patch series "pipe: Trivial cleanups" 

K Prateek Nayak <kprateek.nayak@amd.com> says:

Based on the suggestion on the RFC, the treewide conversion of
references to pipe->{head,tail} from unsigned int to pipe_index_t has
been dropped for now. The series contains trivial cleanup suggested to
limit the nr_slots in pipe_resize_ring() to be covered between
pipe_index_t limits of pipe->{head,tail} and using pipe_buf() to remove
the open-coded usage of masks to access pipe buffer building on Linus'
cleanup of fs/fuse/dev.c in commit ebb0f38b ("fs/pipe: fix pipe
buffer index use in FUSE")

* patches from https://lore.kernel.org/r/20250307052919.34542-1-kprateek.nayak@amd.com:
  fs/splice: Use pipe_buf() helper to retrieve pipe buffer
  fs/pipe: Use pipe_buf() helper to retrieve pipe buffer
  kernel/watch_queue: Use pipe_buf() to retrieve the pipe buffer
  fs/pipe: Limit the slots in pipe_resize_ring()

Link: https://lore.kernel.org/r/20250307052919.34542-1-kprateek.nayak@amd.com


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 38962d9b d5c6cb01

fs/pipe.c

+7 −6
Original line number Diff line number Diff line
@@ -294,7 +294,6 @@ anon_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) {
@@ -321,7 +320,7 @@ anon_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;
@@ -477,8 +476,7 @@ anon_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) &&
@@ -509,7 +507,6 @@ anon_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;

			int copied;
@@ -531,7 +528,7 @@ anon_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;
@@ -1293,6 +1290,10 @@ int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots) 
	struct pipe_buffer *bufs;

	unsigned int head, tail, mask, n;



	/* nr_slots larger than limits of pipe->{head,tail} */

	if (unlikely(nr_slots > (pipe_index_t)-1u))

		return -EINVAL;



	bufs = kcalloc(nr_slots, sizeof(*bufs),

		       GFP_KERNEL_ACCOUNT | __GFP_NOWARN);

	if (unlikely(!bufs))

fs/splice.c

+14 −26
Original line number Diff line number Diff line
@@ -200,7 +200,6 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 
	unsigned int spd_pages = spd->nr_pages;

	unsigned int tail = pipe->tail;

	unsigned int head = pipe->head;

	unsigned int mask = pipe->ring_size - 1;

	ssize_t ret = 0;

	int page_nr = 0;
@@ -214,7 +213,7 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe, 
	}



	while (!pipe_full(head, tail, pipe->max_usage)) {

		struct pipe_buffer *buf = &pipe->bufs[head & mask];

		struct pipe_buffer *buf = pipe_buf(pipe, head);



		buf->page = spd->pages[page_nr];

		buf->offset = spd->partial[page_nr].offset;
@@ -247,7 +246,6 @@ ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf) 
{

	unsigned int head = pipe->head;

	unsigned int tail = pipe->tail;

	unsigned int mask = pipe->ring_size - 1;

	int ret;



	if (unlikely(!pipe->readers)) {
@@ -256,7 +254,7 @@ ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf) 
	} else if (pipe_full(head, tail, pipe->max_usage)) {

		ret = -EAGAIN;

	} else {

		pipe->bufs[head & mask] = *buf;

		*pipe_buf(pipe, head) = *buf;

		pipe->head = head + 1;

		return buf->len;

	}
@@ -447,11 +445,10 @@ static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_des 
{

	unsigned int head = pipe->head;

	unsigned int tail = pipe->tail;

	unsigned int mask = pipe->ring_size - 1;

	int ret;



	while (!pipe_empty(head, tail)) {

		struct pipe_buffer *buf = &pipe->bufs[tail & mask];

		struct pipe_buffer *buf = pipe_buf(pipe, tail);



		sd->len = buf->len;

		if (sd->len > sd->total_len)
@@ -495,8 +492,7 @@ static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_des 
static inline bool eat_empty_buffer(struct pipe_inode_info *pipe)

{

	unsigned int tail = pipe->tail;

	unsigned int mask = pipe->ring_size - 1;

	struct pipe_buffer *buf = &pipe->bufs[tail & mask];

	struct pipe_buffer *buf = pipe_buf(pipe, tail);



	if (unlikely(!buf->len)) {

		pipe_buf_release(pipe, buf);
@@ -690,7 +686,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 
	while (sd.total_len) {

		struct kiocb kiocb;

		struct iov_iter from;

		unsigned int head, tail, mask;

		unsigned int head, tail;

		size_t left;

		int n;
@@ -711,12 +707,11 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 


		head = pipe->head;

		tail = pipe->tail;

		mask = pipe->ring_size - 1;



		/* build the vector */

		left = sd.total_len;

		for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) {

			struct pipe_buffer *buf = &pipe->bufs[tail & mask];

			struct pipe_buffer *buf = pipe_buf(pipe, tail);

			size_t this_len = buf->len;



			/* zero-length bvecs are not supported, skip them */
@@ -752,7 +747,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, 
		/* dismiss the fully eaten buffers, adjust the partial one */

		tail = pipe->tail;

		while (ret) {

			struct pipe_buffer *buf = &pipe->bufs[tail & mask];

			struct pipe_buffer *buf = pipe_buf(pipe, tail);

			if (ret >= buf->len) {

				ret -= buf->len;

				buf->len = 0;
@@ -809,7 +804,7 @@ ssize_t splice_to_socket(struct pipe_inode_info *pipe, struct file *out, 
	pipe_lock(pipe);



	while (len > 0) {

		unsigned int head, tail, mask, bc = 0;

		unsigned int head, tail, bc = 0;

		size_t remain = len;



		/*
@@ -846,10 +841,9 @@ ssize_t splice_to_socket(struct pipe_inode_info *pipe, struct file *out, 


		head = pipe->head;

		tail = pipe->tail;

		mask = pipe->ring_size - 1;



		while (!pipe_empty(head, tail)) {

			struct pipe_buffer *buf = &pipe->bufs[tail & mask];

			struct pipe_buffer *buf = pipe_buf(pipe, tail);

			size_t seg;



			if (!buf->len) {
@@ -894,7 +888,7 @@ ssize_t splice_to_socket(struct pipe_inode_info *pipe, struct file *out, 
		len -= ret;

		tail = pipe->tail;

		while (ret > 0) {

			struct pipe_buffer *buf = &pipe->bufs[tail & mask];

			struct pipe_buffer *buf = pipe_buf(pipe, tail);

			size_t seg = min_t(size_t, ret, buf->len);



			buf->offset += seg;
@@ -1725,7 +1719,6 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 
	struct pipe_buffer *ibuf, *obuf;

	unsigned int i_head, o_head;

	unsigned int i_tail, o_tail;

	unsigned int i_mask, o_mask;

	int ret = 0;

	bool input_wakeup = false;
@@ -1747,9 +1740,7 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 
	pipe_double_lock(ipipe, opipe);



	i_tail = ipipe->tail;

	i_mask = ipipe->ring_size - 1;

	o_head = opipe->head;

	o_mask = opipe->ring_size - 1;



	do {

		size_t o_len;
@@ -1792,8 +1783,8 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 
			goto retry;

		}



		ibuf = &ipipe->bufs[i_tail & i_mask];

		obuf = &opipe->bufs[o_head & o_mask];

		ibuf = pipe_buf(ipipe, i_tail);

		obuf = pipe_buf(opipe, o_head);



		if (len >= ibuf->len) {

			/*
@@ -1862,7 +1853,6 @@ static ssize_t link_pipe(struct pipe_inode_info *ipipe, 
	struct pipe_buffer *ibuf, *obuf;

	unsigned int i_head, o_head;

	unsigned int i_tail, o_tail;

	unsigned int i_mask, o_mask;

	ssize_t ret = 0;



	/*
@@ -1873,9 +1863,7 @@ static ssize_t link_pipe(struct pipe_inode_info *ipipe, 
	pipe_double_lock(ipipe, opipe);



	i_tail = ipipe->tail;

	i_mask = ipipe->ring_size - 1;

	o_head = opipe->head;

	o_mask = opipe->ring_size - 1;



	do {

		if (!opipe->readers) {
@@ -1896,8 +1884,8 @@ static ssize_t link_pipe(struct pipe_inode_info *ipipe, 
		    pipe_full(o_head, o_tail, opipe->max_usage))

			break;



		ibuf = &ipipe->bufs[i_tail & i_mask];

		obuf = &opipe->bufs[o_head & o_mask];

		ibuf = pipe_buf(ipipe, i_tail);

		obuf = pipe_buf(opipe, o_head);



		/*

		 * Get a reference to this pipe buffer,

kernel/watch_queue.c

+3 −4
Original line number Diff line number Diff line
@@ -101,12 +101,11 @@ static bool post_one_notification(struct watch_queue *wqueue, 
	struct pipe_inode_info *pipe = wqueue->pipe;

	struct pipe_buffer *buf;

	struct page *page;

	unsigned int head, tail, mask, note, offset, len;

	unsigned int head, tail, note, offset, len;

	bool done = false;



	spin_lock_irq(&pipe->rd_wait.lock);



	mask = pipe->ring_size - 1;

	head = pipe->head;

	tail = pipe->tail;

	if (pipe_full(head, tail, pipe->ring_size))
@@ -124,7 +123,7 @@ static bool post_one_notification(struct watch_queue *wqueue, 
	memcpy(p + offset, n, len);

	kunmap_atomic(p);



	buf = &pipe->bufs[head & mask];

	buf = pipe_buf(pipe, head);

	buf->page = page;

	buf->private = (unsigned long)wqueue;

	buf->ops = &watch_queue_pipe_buf_ops;
@@ -147,7 +146,7 @@ static bool post_one_notification(struct watch_queue *wqueue, 
	return done;



lost:

	buf = &pipe->bufs[(head - 1) & mask];

	buf = pipe_buf(pipe, head - 1);

	buf->flags |= PIPE_BUF_FLAG_LOSS;

	goto out;

}