fs/coredump.c | 4 +-- fs/pipe.c | 67 +++++++++++++++++++++++++++++++---------------- fs/splice.c | 8 +++--- include/linux/pipe_fs_i.h | 2 +- 4 files changed, 51 insertions(+), 30 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index b1ea7dfbd149..f8296a82d01d 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -517,7 +517,7 @@ static void wait_for_dump_helpers(struct file *file) pipe_lock(pipe); pipe->readers++; pipe->writers--; - wake_up_interruptible_sync(&pipe->wait); + wake_up_interruptible_sync(&pipe->rd_wait); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); pipe_unlock(pipe); @@ -525,7 +525,7 @@ static void wait_for_dump_helpers(struct file *file) * We actually want wait_event_freezable() but then we need * to clear TIF_SIGPENDING and improve dump_interrupted(). */ - wait_event_interruptible(pipe->wait, pipe->readers == 1); + wait_event_interruptible(pipe->rd_wait, pipe->readers == 1); pipe_lock(pipe); pipe->readers--; diff --git a/fs/pipe.c b/fs/pipe.c index 87109e761fa5..1eb64cab63b5 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -108,16 +108,19 @@ void pipe_double_lock(struct pipe_inode_info *pipe1, /* Drop the inode semaphore and wait for a pipe event, atomically */ void pipe_wait(struct pipe_inode_info *pipe) { - DEFINE_WAIT(wait); + DEFINE_WAIT(rdwait); + DEFINE_WAIT(wrwait); /* * Pipes are system-local resources, so sleeping on them * is considered a noninteractive wait: */ - prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE); + prepare_to_wait(&pipe->rd_wait, &rdwait, TASK_INTERRUPTIBLE); + prepare_to_wait(&pipe->wr_wait, &wrwait, TASK_INTERRUPTIBLE); pipe_unlock(pipe); schedule(); - finish_wait(&pipe->wait, &wait); + finish_wait(&pipe->rd_wait, &rdwait); + finish_wait(&pipe->wr_wait, &wrwait); pipe_lock(pipe); } @@ -286,7 +289,7 @@ 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; + bool was_full, wake_next_reader = false; ssize_t ret; /* Null read succeeds. */ @@ -344,10 +347,10 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to) if (!buf->len) { pipe_buf_release(pipe, buf); - spin_lock_irq(&pipe->wait.lock); + spin_lock_irq(&pipe->rd_wait.lock); tail++; pipe->tail = tail; - spin_unlock_irq(&pipe->wait.lock); + spin_unlock_irq(&pipe->rd_wait.lock); } total_len -= chars; if (!total_len) @@ -371,19 +374,24 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to) } __pipe_unlock(pipe); if (was_full) { - wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT | EPOLLWRNORM); + wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); } - wait_event_interruptible(pipe->wait, pipe_readable(pipe)); + wait_event_interruptible_exclusive(pipe->rd_wait, pipe_readable(pipe)); __pipe_lock(pipe); was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage); + wake_next_reader = true; } + if (pipe_empty(pipe->head, pipe->tail)) + wake_next_reader = false; __pipe_unlock(pipe); if (was_full) { - wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT | EPOLLWRNORM); + wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); } + if (wake_next_reader) + wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM); if (ret > 0) file_accessed(filp); return ret; @@ -415,6 +423,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) size_t total_len = iov_iter_count(from); ssize_t chars; bool was_empty = false; + bool wake_next_writer = false; /* Null write succeeds. */ if (unlikely(total_len == 0)) @@ -493,16 +502,16 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) * it, either the reader will consume it or it'll still * be there for the next write. */ - spin_lock_irq(&pipe->wait.lock); + spin_lock_irq(&pipe->rd_wait.lock); head = pipe->head; if (pipe_full(head, pipe->tail, pipe->max_usage)) { - spin_unlock_irq(&pipe->wait.lock); + spin_unlock_irq(&pipe->rd_wait.lock); continue; } pipe->head = head + 1; - spin_unlock_irq(&pipe->wait.lock); + spin_unlock_irq(&pipe->rd_wait.lock); /* Insert it into the buffer array */ buf = &pipe->bufs[head & mask]; @@ -554,14 +563,17 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) */ __pipe_unlock(pipe); if (was_empty) { - wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN | EPOLLRDNORM); + wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); } - wait_event_interruptible(pipe->wait, pipe_writable(pipe)); + wait_event_interruptible_exclusive(pipe->wr_wait, pipe_writable(pipe)); __pipe_lock(pipe); was_empty = pipe_empty(head, pipe->tail); + wake_next_writer = true; } out: + if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) + wake_next_writer = false; __pipe_unlock(pipe); /* @@ -574,9 +586,11 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) * wake up pending jobs */ if (was_empty) { - wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN | EPOLLRDNORM); + wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); } + if (wake_next_writer) + wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM); if (ret > 0 && sb_start_write_trylock(file_inode(filp)->i_sb)) { int err = file_update_time(filp); if (err) @@ -620,12 +634,15 @@ pipe_poll(struct file *filp, poll_table *wait) unsigned int head, tail; /* - * Reading only -- no need for acquiring the semaphore. + * Reading pipe state only -- no need for acquiring the semaphore. * * But because this is racy, the code has to add the * entry to the poll table _first_ .. */ - poll_wait(filp, &pipe->wait, wait); + if (filp->f_mode & FMODE_READ) + poll_wait(filp, &pipe->rd_wait, wait); + if (filp->f_mode & FMODE_WRITE) + poll_wait(filp, &pipe->wr_wait, wait); /* * .. and only then can you do the racy tests. That way, @@ -684,7 +701,8 @@ pipe_release(struct inode *inode, struct file *file) pipe->writers--; if (pipe->readers || pipe->writers) { - wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN | EPOLLOUT | EPOLLRDNORM | EPOLLWRNORM | EPOLLERR | EPOLLHUP); + wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLHUP); + wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM | EPOLLERR | EPOLLHUP); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); } @@ -767,7 +785,8 @@ struct pipe_inode_info *alloc_pipe_info(void) GFP_KERNEL_ACCOUNT); if (pipe->bufs) { - init_waitqueue_head(&pipe->wait); + init_waitqueue_head(&pipe->rd_wait); + init_waitqueue_head(&pipe->wr_wait); pipe->r_counter = pipe->w_counter = 1; pipe->max_usage = pipe_bufs; pipe->ring_size = pipe_bufs; @@ -985,7 +1004,8 @@ static int wait_for_partner(struct pipe_inode_info *pipe, unsigned int *cnt) static void wake_up_partner(struct pipe_inode_info *pipe) { - wake_up_interruptible(&pipe->wait); + wake_up_interruptible(&pipe->rd_wait); + wake_up_interruptible(&pipe->wr_wait); } static int fifo_open(struct inode *inode, struct file *filp) @@ -1096,13 +1116,13 @@ static int fifo_open(struct inode *inode, struct file *filp) err_rd: if (!--pipe->readers) - wake_up_interruptible(&pipe->wait); + wake_up_interruptible(&pipe->wr_wait); ret = -ERESTARTSYS; goto err; err_wr: if (!--pipe->writers) - wake_up_interruptible(&pipe->wait); + wake_up_interruptible(&pipe->rd_wait); ret = -ERESTARTSYS; goto err; @@ -1229,7 +1249,8 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg) pipe->max_usage = nr_slots; pipe->tail = tail; pipe->head = head; - wake_up_interruptible_all(&pipe->wait); + wake_up_interruptible_all(&pipe->rd_wait); + wake_up_interruptible_all(&pipe->wr_wait); return pipe->max_usage * PAGE_SIZE; out_revert_acct: diff --git a/fs/splice.c b/fs/splice.c index 3009652a41c8..d671936d0aad 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -165,8 +165,8 @@ static const struct pipe_buf_operations user_page_pipe_buf_ops = { static void wakeup_pipe_readers(struct pipe_inode_info *pipe) { smp_mb(); - if (waitqueue_active(&pipe->wait)) - wake_up_interruptible(&pipe->wait); + if (waitqueue_active(&pipe->rd_wait)) + wake_up_interruptible(&pipe->rd_wait); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); } @@ -462,8 +462,8 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe, static void wakeup_pipe_writers(struct pipe_inode_info *pipe) { smp_mb(); - if (waitqueue_active(&pipe->wait)) - wake_up_interruptible(&pipe->wait); + if (waitqueue_active(&pipe->wr_wait)) + wake_up_interruptible(&pipe->wr_wait); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); } diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index dbcfa6892384..d5765039652a 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -47,7 +47,7 @@ struct pipe_buffer { **/ struct pipe_inode_info { struct mutex mutex; - wait_queue_head_t wait; + wait_queue_head_t rd_wait, wr_wait; unsigned int head; unsigned int tail; unsigned int max_usage;