kernfs: add back missing error check in kernfs_fop_mmap()
authorTejun Heo <tj@kernel.org>
Sun, 20 Apr 2014 12:29:21 +0000 (08:29 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 25 Apr 2014 19:25:13 +0000 (12:25 -0700)
commitb44b2140265ddfde03acbe809336111d31adb0d1
tree816005d20738096829c9730747eba6373ce3cd04
parentc1befb885939cdaaf420c10bbe9ff57aa00446ea
kernfs: add back missing error check in kernfs_fop_mmap()

While updating how mmap enabled kernfs files are handled by lockdep,
9b2db6e18945 ("sysfs: bail early from kernfs_file_mmap() to avoid
spurious lockdep warning") inadvertently dropped error return check
from kernfs_file_mmap().  The intention was just dropping "if
(ops->mmap)" check as the control won't reach the point if the mmap
callback isn't implemented, but I mistakenly removed the error return
check together with it.

This led to Xorg crash on i810 which was reported and bisected to the
commit and then to the specific change by Tobias.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-bisected-by: Tobias Powalowski <tobias.powalowski@googlemail.com>
Tested-by: Tobias Powalowski <tobias.powalowski@googlemail.com>
References: http://lkml.kernel.org/g/533D01BD.1010200@googlemail.com
Cc: stable <stable@vger.kernel.org> # 3.14
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fs/kernfs/file.c