[RFC 2/2] drm/i915: Handle validation of relocation object with length >=2GB

[Sagar Arun Kamble]

With prefaulting extended to support >=2GB, i915 can handle
relocation objects >=2GB. type conversion of length from int to
unsigned long in access_ok was making the validation bail out with
-EFAULT.

Testcase: igt/gem_exec_reloc/wc-31
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Sagar Arun Kamble <sagar.a.kamble at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_execbuffer.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 91c2393..db2c40e 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1159,8 +1159,8 @@ static bool only_mappable_for_reloc(unsigned int flags)
 		   struct drm_i915_gem_exec_object2 *exec,
 		   int count)
 {
-	unsigned relocs_total = 0;
-	unsigned relocs_max = UINT_MAX / sizeof(struct drm_i915_gem_relocation_entry);
+	unsigned long relocs_total = 0;
+	unsigned long relocs_max = ULONG_MAX / sizeof(struct drm_i915_gem_relocation_entry);
 	unsigned invalid_flags;
 	int i;
 
@@ -1173,7 +1173,7 @@ static bool only_mappable_for_reloc(unsigned int flags)
 
 	for (i = 0; i < count; i++) {
 		char __user *ptr = u64_to_user_ptr(exec[i].relocs_ptr);
-		int length; /* limited by fault_in_pages_readable() */
+		unsigned long length;
 
 		if (exec[i].flags & invalid_flags)
 			return -EINVAL;
-- 
1.9.1