packet: Avoid lock_sock in mmap handler
authorHerbert Xu <herbert@gondor.apana.org.au>
Fri, 30 Jan 2009 22:12:06 +0000 (14:12 -0800)
committerDavid S. Miller <davem@davemloft.net>
Fri, 30 Jan 2009 22:13:49 +0000 (14:13 -0800)
commit905db44087855e3c1709f538ecdc22fd149cadd8
tree645708af472fd26bb73b5cd6abe10640322a3b93
parent1974cc205e63cec4a17a6b3fca31fa4240ded77e
packet: Avoid lock_sock in mmap handler

As the mmap handler gets called under mmap_sem, and we may grab
mmap_sem elsewhere under the socket lock to access user data, we
should avoid grabbing the socket lock in the mmap handler.

Since the only thing we care about in the mmap handler is for
pg_vec* to be invariant, i.e., to exclude packet_set_ring, we
can achieve this by simply using a new mutex.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Martin MOKREJ┼á <mmokrejs@ribosome.natur.cuni.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/packet/af_packet.c