[Intel-gfx] [PATCH] drm/i915/gem: Ignore readonly failures when updating relocs

[Chris Wilson]

If the user passes in a readonly reloc[], by the time we notice we have
already commited to modifying the execobjects, or have indeed done so
already. Reporting the failure just compounds the issue as we have no
second pass to fall back to anymore.

Testcase: igt/gem_exec_reloc/readonly
Fixes: 7dc8f1143778 ("drm/i915/gem: Drop relocation slowpath")
References: fddcd00a49e9 ("drm/i915: Force the slow path after a user-write error")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index cda35e6dfc44..bc8aa9604787 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -1540,10 +1540,8 @@ static int eb_relocate_vma(struct i915_execbuffer *eb, struct eb_vma *ev)
 				 * can read from this userspace address.
 				 */
 				offset = gen8_canonical_addr(offset & ~UPDATE);
-				if (unlikely(__put_user(offset, &urelocs[r-stack].presumed_offset))) {
-					remain = -EFAULT;
-					goto out;
-				}
+				__put_user(offset,
+					   &urelocs[r-stack].presumed_offset);
 			}
 		} while (r++, --count);
 		urelocs += ARRAY_SIZE(stack);
-- 
2.20.1