drm/i915: Report -EFAULT before pwrite fast path into shmemfs
authorChris Wilson <chris@chris-wilson.co.uk>
Mon, 16 Oct 2017 20:27:32 +0000 (21:27 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Tue, 17 Oct 2017 13:07:47 +0000 (14:07 +0100)
commita6d65e451cc4e7127698384868a4447ee7be7d16
treef7aa656bc04034159ac9392e70dc974789975a77
parent1d7765380f66648d979e33da92bbb49c64c12e61
drm/i915: Report -EFAULT before pwrite fast path into shmemfs

When pwriting into shmemfs, the fast path pagecache_write does not
notice when it is writing to beyond the end of the truncated shmemfs
inode. Report -EFAULT directly when we try to use pwrite into the
!I915_MADV_WILLNEED object.

Fixes: 7c55e2c5772d ("drm/i915: Use pagecache write to prepopulate shmemfs from pwrite-ioctl")
Testcase: igt/gem_madvise/dontneed-before-pwrite
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171016202732.25459-1-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/i915_gem.c