Commit 721017cf authored Mar 31, 2020 by Chris Wilson Committed by Rodrigo Vivi Apr 06, 2020

drm/i915/gem: Ignore readonly failures when updating relocs



If the user passes in a readonly reloc[], by the time we notice we have
already committed 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.

"Be damned if you do, and damned if you don't."

Testcase: igt/gem_exec_reloc/readonly
Fixes: 7dc8f114 ("drm/i915/gem: Drop relocation slowpath")
References: fddcd00a ("drm/i915: Force the slow path after a user-write error")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200331162150.3635-1-chris@chris-wilson.co.uk


(cherry picked from commit 97a37c91)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

parent 0b72a251

drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -1477,10 +1477,8 @@ 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);

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