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-rw-r--r--fs/pipe.c59
1 files changed, 31 insertions, 28 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index 12b22c2723b7..4d0799e4e719 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -210,11 +210,10 @@ static const struct pipe_buf_operations 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)
{
- unsigned int head = READ_ONCE(pipe->head);
- unsigned int tail = READ_ONCE(pipe->tail);
+ union pipe_index idx = { .head_tail = READ_ONCE(pipe->head_tail) };
unsigned int writers = READ_ONCE(pipe->writers);
- return !pipe_empty(head, tail) || !writers;
+ return !pipe_empty(idx.head, idx.tail) || !writers;
}
static inline unsigned int pipe_update_tail(struct pipe_inode_info *pipe,
@@ -253,7 +252,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
size_t total_len = iov_iter_count(to);
struct file *filp = iocb->ki_filp;
struct pipe_inode_info *pipe = filp->private_data;
- bool was_full, wake_next_reader = false;
+ bool wake_writer = false, wake_next_reader = false;
ssize_t ret;
/* Null read succeeds. */
@@ -264,14 +263,13 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
mutex_lock(&pipe->mutex);
/*
- * We only wake up writers if the pipe was full when we started
- * reading in order to avoid unnecessary wakeups.
+ * We only wake up writers if the pipe was full when we started reading
+ * and it is no longer full after reading to avoid unnecessary wakeups.
*
* But when we do wake up writers, we do so using a sync wakeup
* (WF_SYNC), because we want them to get going and generate more
* data for us.
*/
- was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage);
for (;;) {
/* Read ->head with a barrier vs post_one_notification() */
unsigned int head = smp_load_acquire(&pipe->head);
@@ -340,8 +338,10 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
buf->len = 0;
}
- if (!buf->len)
+ if (!buf->len) {
+ wake_writer |= pipe_full(head, tail, pipe->max_usage);
tail = pipe_update_tail(pipe, buf, tail);
+ }
total_len -= chars;
if (!total_len)
break; /* common path: read succeeded */
@@ -377,7 +377,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
* _very_ unlikely case that the pipe was full, but we got
* no data.
*/
- if (unlikely(was_full))
+ if (unlikely(wake_writer))
wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
@@ -390,15 +390,15 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
if (wait_event_interruptible_exclusive(pipe->rd_wait, pipe_readable(pipe)) < 0)
return -ERESTARTSYS;
- mutex_lock(&pipe->mutex);
- was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage);
+ wake_writer = false;
wake_next_reader = true;
+ mutex_lock(&pipe->mutex);
}
- if (pipe_empty(pipe->head, pipe->tail))
+ if (pipe_is_empty(pipe))
wake_next_reader = false;
mutex_unlock(&pipe->mutex);
- if (was_full)
+ if (wake_writer)
wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM);
if (wake_next_reader)
wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
@@ -416,11 +416,10 @@ static inline int is_packetized(struct file *file)
/* Done while waiting without holding the pipe lock - thus the READ_ONCE() */
static inline bool pipe_writable(const struct pipe_inode_info *pipe)
{
- unsigned int head = READ_ONCE(pipe->head);
- unsigned int tail = READ_ONCE(pipe->tail);
+ union pipe_index idx = { .head_tail = READ_ONCE(pipe->head_tail) };
unsigned int max_usage = READ_ONCE(pipe->max_usage);
- return !pipe_full(head, tail, max_usage) ||
+ return !pipe_full(idx.head, idx.tail, max_usage) ||
!READ_ONCE(pipe->readers);
}
@@ -578,11 +577,11 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
wait_event_interruptible_exclusive(pipe->wr_wait, pipe_writable(pipe));
mutex_lock(&pipe->mutex);
- was_empty = pipe_empty(pipe->head, pipe->tail);
+ was_empty = pipe_is_empty(pipe);
wake_next_writer = true;
}
out:
- if (pipe_full(pipe->head, pipe->tail, pipe->max_usage))
+ if (pipe_is_full(pipe))
wake_next_writer = false;
mutex_unlock(&pipe->mutex);
@@ -615,7 +614,7 @@ out:
static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct pipe_inode_info *pipe = filp->private_data;
- unsigned int count, head, tail, mask;
+ unsigned int count, head, tail;
switch (cmd) {
case FIONREAD:
@@ -623,10 +622,9 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
count = 0;
head = pipe->head;
tail = pipe->tail;
- mask = pipe->ring_size - 1;
- while (tail != head) {
- count += pipe->bufs[tail & mask].len;
+ while (!pipe_empty(head, tail)) {
+ count += pipe_buf(pipe, tail)->len;
tail++;
}
mutex_unlock(&pipe->mutex);
@@ -658,7 +656,7 @@ pipe_poll(struct file *filp, poll_table *wait)
{
__poll_t mask;
struct pipe_inode_info *pipe = filp->private_data;
- unsigned int head, tail;
+ union pipe_index idx;
/* Epoll has some historical nasty semantics, this enables them */
WRITE_ONCE(pipe->poll_usage, true);
@@ -679,19 +677,18 @@ pipe_poll(struct file *filp, poll_table *wait)
* if something changes and you got it wrong, the poll
* table entry will wake you up and fix it.
*/
- head = READ_ONCE(pipe->head);
- tail = READ_ONCE(pipe->tail);
+ idx.head_tail = READ_ONCE(pipe->head_tail);
mask = 0;
if (filp->f_mode & FMODE_READ) {
- if (!pipe_empty(head, tail))
+ if (!pipe_empty(idx.head, idx.tail))
mask |= EPOLLIN | EPOLLRDNORM;
if (!pipe->writers && filp->f_pipe != pipe->w_counter)
mask |= EPOLLHUP;
}
if (filp->f_mode & FMODE_WRITE) {
- if (!pipe_full(head, tail, pipe->max_usage))
+ if (!pipe_full(idx.head, idx.tail, pipe->max_usage))
mask |= EPOLLOUT | EPOLLWRNORM;
/*
* Most Unices do not set EPOLLERR for FIFOs but on Linux they
@@ -959,6 +956,12 @@ int create_pipe_files(struct file **res, int flags)
res[1] = f;
stream_open(inode, res[0]);
stream_open(inode, res[1]);
+ /*
+ * Disable permission and pre-content events, but enable legacy
+ * inotify events for legacy users.
+ */
+ file_set_fsnotify_mode(res[0], FMODE_NONOTIFY_PERM);
+ file_set_fsnotify_mode(res[1], FMODE_NONOTIFY_PERM);
return 0;
}
@@ -1477,7 +1480,7 @@ static int proc_dopipe_max_size(const struct ctl_table *table, int write,
do_proc_dopipe_max_size_conv, NULL);
}
-static struct ctl_table fs_pipe_sysctls[] = {
+static const struct ctl_table fs_pipe_sysctls[] = {
{
.procname = "pipe-max-size",
.data = &pipe_max_size,
generated by cgit v1.2.3 (git 2.39.0) at 2025-04-30 10:57:08 +0300