pipe: Advance tail pointer inside of wait spinlock in pipe_read() (b667b867) · Commits · 戴 / test

Advance the pipe ring tail pointer inside of wait spinlock in pipe_read() so that the pipe can be written into with kernel notifications from contexts where pipe->mutex cannot be taken. Signed-off-by:

David Howells <dhowells@redhat.com>

fs/pipe.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -325,9 +325,14 @@ pipe_read(struct kiocb iocb, struct iov_iter to)

		if (!buf->len) {
		pipe_buf_release(pipe, buf);
		spin_lock_irq(&pipe->wait.lock);
		tail++;
		pipe->tail = tail;
		do_wakeup = 1;
		do_wakeup = 0;
		wake_up_interruptible_sync_poll_locked(
		&pipe->wait, EPOLLOUT \| EPOLLWRNORM);
		spin_unlock_irq(&pipe->wait.lock);
		kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
		}
		total_len -= chars;
		if (!total_len)
		@@ -359,6 +364,7 @@ pipe_read(struct kiocb iocb, struct iov_iter to)
		if (do_wakeup) {
		wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT \| EPOLLWRNORM);
		kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
		do_wakeup = 0;
		}
		pipe_wait(pipe);
		}

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