Commit ca8d7822 authored by Chris Wilson's avatar Chris Wilson Committed by Rodrigo Vivi

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: 7c55e2c5 ("drm/i915: Use pagecache write to prepopulate shmemfs from pwrite-ioctl")
Testcase: igt/gem_madvise/dontneed-before-pwrite
Signed-off-by: default avatarChris 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: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171016202732.25459-1-chris@chris-wilson.co.uk
(cherry picked from commit a6d65e45)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
parent 038daf55
...@@ -2657,6 +2657,9 @@ i915_gem_object_pwrite_gtt(struct drm_i915_gem_object *obj, ...@@ -2657,6 +2657,9 @@ i915_gem_object_pwrite_gtt(struct drm_i915_gem_object *obj,
if (READ_ONCE(obj->mm.pages)) if (READ_ONCE(obj->mm.pages))
return -ENODEV; return -ENODEV;
if (obj->mm.madv != I915_MADV_WILLNEED)
return -EFAULT;
/* Before the pages are instantiated the object is treated as being /* Before the pages are instantiated the object is treated as being
* in the CPU domain. The pages will be clflushed as required before * in the CPU domain. The pages will be clflushed as required before
* use, and we can freely write into the pages directly. If userspace * use, and we can freely write into the pages directly. If userspace
......
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