xen-netfront: fix resource leak in netfront
authorAnnie Li <annie.li@oracle.com>
Tue, 28 Jan 2014 03:35:42 +0000 (11:35 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 6 Feb 2014 19:08:17 +0000 (11:08 -0800)
commit64cee83a9856e8fa4cb6616a072469d5eba3c1d7
tree37784694043ad6811be6a6974ecf59064c06c416
parent873c4941de470ec803d409150df3d9d4b705f578
xen-netfront: fix resource leak in netfront

[ Upstream commit cefe0078eea52af17411eb1248946a94afb84ca5 ]

This patch removes grant transfer releasing code from netfront, and uses
gnttab_end_foreign_access to end grant access since
gnttab_end_foreign_access_ref may fail when the grant entry is
currently used for reading or writing.

* clean up grant transfer code kept from old netfront(2.6.18) which grants
pages for access/map and transfer. But grant transfer is deprecated in current
netfront, so remove corresponding release code for transfer.

* fix resource leak, release grant access (through gnttab_end_foreign_access)
and skb for tx/rx path, use get_page to ensure page is released when grant
access is completed successfully.

Xen-blkfront/xen-tpmfront/xen-pcifront also have similar issue, but patches
for them will be created separately.

V6: Correct subject line and commit message.

V5: Remove unecessary change in xennet_end_access.

V4: Revert put_page in gnttab_end_foreign_access, and keep netfront change in
single patch.

V3: Changes as suggestion from David Vrabel, ensure pages are not freed untill
grant acess is ended.

V2: Improve patch comments.

Signed-off-by: Annie Li <annie.li@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/net/xen-netfront.c