From: Eric Dumazet Date: Thu, 6 Jan 2011 18:54:29 +0000 (-0800) Subject: net: add POLLPRI to sock_def_readable() X-Git-Tag: v2.6.37.1~133 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ed12313af40575c71b1b6533576f6d5dd9cc39b0;p=pandora-kernel.git net: add POLLPRI to sock_def_readable() [ Upstream commit 2c6607c611cb7bf0a6750bcea34a258144e302c5 ] Leonardo Chiquitto found poll() could block forever on tcp sockets and Urgent data was received, if the event flag only contains POLLPRI. He did a bisection and found commit 4938d7e0233 (poll: avoid extra wakeups in select/poll) was the source of the problem. Problem is TCP sockets use standard sock_def_readable() function for their sk_data_ready() handler, and sock_def_readable() doesnt signal POLLPRI. Only TCP is affected by the problem. Adding POLLPRI to the list of flags might trigger unnecessary schedules, but URGENT handling is such a seldom used feature this seems a good compromise. Thanks a lot to Leonardo for providing the bisection result and a test program as well. Reference : http://www.spinics.net/lists/netdev/msg151793.html Reported-and-bisected-by: Leonardo Chiquitto Signed-off-by: Eric Dumazet Tested-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed