diff options
author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-23 06:59:19 -0500 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-23 06:59:19 -0500 |
commit | 749e4121d6ee7fd4495779730fbc6ae800d0317c (patch) | |
tree | 9270ebabd9e3b57ef0427495ec9228f52454b608 /fs/pipe.c | |
parent | tty: serial: 21285: stop using the unused[] variable from struct uart_port (diff) | |
parent | Linux 5.5-rc3 (diff) | |
download | linux-dev-749e4121d6ee7fd4495779730fbc6ae800d0317c.tar.xz linux-dev-749e4121d6ee7fd4495779730fbc6ae800d0317c.zip |
Merge 5.5-rc3 into tty-next
We need the tty/serial fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/pipe.c')
-rw-r--r-- | fs/pipe.c | 38 |
1 files changed, 30 insertions, 8 deletions
diff --git a/fs/pipe.c b/fs/pipe.c index 87109e761fa5..57502c3c0fba 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -364,17 +364,39 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to) ret = -EAGAIN; break; } - if (signal_pending(current)) { - if (!ret) - ret = -ERESTARTSYS; - break; - } __pipe_unlock(pipe); - if (was_full) { + + /* + * We only get here if we didn't actually read anything. + * + * However, we could have seen (and removed) a zero-sized + * pipe buffer, and might have made space in the buffers + * that way. + * + * You can't make zero-sized pipe buffers by doing an empty + * write (not even in packet mode), but they can happen if + * the writer gets an EFAULT when trying to fill a buffer + * that already got allocated and inserted in the buffer + * array. + * + * So we still need to wake up any pending writers in the + * _very_ unlikely case that the pipe was full, but we got + * no data. + */ + if (unlikely(was_full)) { wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT | EPOLLWRNORM); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); } - wait_event_interruptible(pipe->wait, pipe_readable(pipe)); + + /* + * But because we didn't read anything, at this point we can + * just return directly with -ERESTARTSYS if we're interrupted, + * since we've done any required wakeups and there's no need + * to mark anything accessed. And we've dropped the lock. + */ + if (wait_event_interruptible(pipe->wait, pipe_readable(pipe)) < 0) + return -ERESTARTSYS; + __pipe_lock(pipe); was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage); } @@ -559,7 +581,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) } wait_event_interruptible(pipe->wait, pipe_writable(pipe)); __pipe_lock(pipe); - was_empty = pipe_empty(head, pipe->tail); + was_empty = pipe_empty(pipe->head, pipe->tail); } out: __pipe_unlock(pipe); |