drm/amdgpu: make amdgpu_mn_get wait for mmap_sem killable
authorMichal Hocko <mhocko@suse.com>
Mon, 23 May 2016 23:26:17 +0000 (16:26 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 24 May 2016 00:04:14 +0000 (17:04 -0700)
amdgpu_mn_get which is called during ioct path relies on mmap_sem for
write.  If the waiting task gets killed by the oom killer it would block
oom_reaper from asynchronous address space reclaim and reduce the
chances of timely OOM resolving.  Wait for the lock in the killable mode
and return with EINTR if the task got killed while waiting.

[arnd@arndb.de: use ERR_PTR() to return from amdgpu_mn_get]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Christian K├Ânig <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

index 9f4a45cd2aab8f5db8c2ce6e086e472697e2f4fe..32fa7b7913f787263548299e9dc5e7c788ca41a4 100644 (file)
@@ -232,7 +232,10 @@ static struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev)
        int r;
-       down_write(&mm->mmap_sem);
+       if (down_write_killable(&mm->mmap_sem)) {
+               mutex_unlock(&adev->mn_lock);
+               return ERR_PTR(-EINTR);
+       }
        hash_for_each_possible(adev->mn_hash, rmn, node, (unsigned long)mm)
                if (rmn->mm == mm)