Commit 52bce911 authored by Linus Torvalds's avatar Linus Torvalds

splice: reinstate SIGPIPE/EPIPE handling

Commit 8924feff ("splice: lift pipe_lock out of splice_to_pipe()")
caused a regression when there were no more readers left on a pipe that
was being spliced into: rather than the expected SIGPIPE and -EPIPE
return value, the writer would end up waiting forever for space to free
up (which obviously was not going to happen with no readers around).

Fixes: 8924feff ("splice: lift pipe_lock out of splice_to_pipe()")
Reported-and-tested-by: default avatarAndreas Schwab <schwab@linux-m68k.org>
Debugged-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org   # v4.9
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0c961c55
...@@ -1087,7 +1087,13 @@ EXPORT_SYMBOL(do_splice_direct); ...@@ -1087,7 +1087,13 @@ EXPORT_SYMBOL(do_splice_direct);
static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags)
{ {
while (pipe->nrbufs == pipe->buffers) { for (;;) {
if (unlikely(!pipe->readers)) {
send_sig(SIGPIPE, current, 0);
return -EPIPE;
}
if (pipe->nrbufs != pipe->buffers)
return 0;
if (flags & SPLICE_F_NONBLOCK) if (flags & SPLICE_F_NONBLOCK)
return -EAGAIN; return -EAGAIN;
if (signal_pending(current)) if (signal_pending(current))
...@@ -1096,7 +1102,6 @@ static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) ...@@ -1096,7 +1102,6 @@ static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags)
pipe_wait(pipe); pipe_wait(pipe);
pipe->waiting_writers--; pipe->waiting_writers--;
} }
return 0;
} }
static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
......
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