[RFC PATCH 032/162] drm/i915: Add object locking to vm_fault_cpu

[Matthew Auld]

From: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>

Take a simple lock so we hold ww around (un)pin_pages as needed.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_mman.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index c0034d811e50..163208a6260d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -246,6 +246,9 @@ static vm_fault_t vm_fault_cpu(struct vm_fault *vmf)
 		     area->vm_flags & VM_WRITE))
 		return VM_FAULT_SIGBUS;
 
+	if (i915_gem_object_lock_interruptible(obj, NULL))
+		return VM_FAULT_NOPAGE;
+
 	err = i915_gem_object_pin_pages(obj);
 	if (err)
 		goto out;
@@ -269,6 +272,7 @@ static vm_fault_t vm_fault_cpu(struct vm_fault *vmf)
 	i915_gem_object_unpin_pages(obj);
 
 out:
+	i915_gem_object_unlock(obj);
 	return i915_error_to_vmf_fault(err);
 }
 
-- 
2.26.2