[PATCH 1/7] drm/panfrost: Don't WARN when a GEM mapping cannot get its pages

[Arun Iyengar via B4 Relay]

From: Arun Iyengar <aiyengar1990@xxxxxxxxx>

panfrost_mmu_map() gets the pages of a BO with
drm_gem_shmem_get_pages_sgt(), which fails with -ENOMEM when shmem
cannot allocate them, for instance when the caller's memory cgroup is at
its limit, or with -EINTR when the caller is being killed. Those are
ordinary failures that reach userspace as an error (Mesa reports
"DRM_IOCTL_PANFROST_CREATE_BO failed (err=12)"), not driver bugs, but
the WARN_ON() turns each of them into a kernel warning with a backtrace:

  WARNING: drivers/gpu/drm/panfrost/panfrost_mmu.c:478 at panfrost_mmu_map+0xcc

dEQP-GLES31.functional.draw_indirect.compute_interop.large.* run in a
600 MB memory cgroup on a 1 GB Mali-G31 board prints it five times.

Return the error without the warning. No pages are held at this point,
so there is nothing to undo.

Fixes: f3ba91228e8e ("drm/panfrost: Add initial panfrost driver")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Arun Iyengar <aiyengar1990@xxxxxxxxx>
---
 drivers/gpu/drm/panfrost/panfrost_mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index faa62643c..56e642f73 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -480,7 +480,7 @@ int panfrost_mmu_map(struct panfrost_gem_mapping *mapping)
 		prot |= IOMMU_NOEXEC;
 
 	sgt = drm_gem_shmem_get_pages_sgt(shmem);
-	if (WARN_ON(IS_ERR(sgt)))
+	if (IS_ERR(sgt))
 		return PTR_ERR(sgt);
 
 	ret = mmu_map_sg(pfdev, mapping->mmu, mapping->mmnode.start << PAGE_SHIFT,

-- 
2.55.0