Otherwise we risk sleeping with the pipe locked for indeterminate
lengths of time ‒ given:
cat > unix.c <<^D
#define _GNU_SOURCE
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/un.h>
int main()
{
int sp[2];
socketpair(AF_UNIX, SOCK_STREAM, 0, sp);
for (;;)
splice(sp[0], 0, 1, 0, 128 * 1024 * 1024, 0);
}
^D
cc unix.c -o unix
mkfifo fifo
./unix > fifo &
read -r _ < fifo &
sleep 0.1
echo zupa > fifo
unix used to sleep in splice and the shell used to enter an
uninterruptible sleep in open("fifo");
now the splice returns -EAGAIN and the whole program completes.
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@xxxxxxxxxxxxxxxxxx>
---
net/unix/af_unix.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index ac1f2bc18fc9..bae84552bf58 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2921,15 +2921,12 @@ static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
.pipe = pipe,
.size = size,
.splice_flags = flags,
+ .flags = MSG_DONTWAIT,
};
if (unlikely(*ppos))
return -ESPIPE;
- if (sock->file->f_flags & O_NONBLOCK ||
- flags & SPLICE_F_NONBLOCK)
- state.flags = MSG_DONTWAIT;
-
return unix_stream_read_generic(&state, false);
}
--
2.39.2
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