4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit ca22f32a6296cbfa29de56328c8505560a18cfa8 ]

Legacy behaviour was to allow non-page-aligned mmap requests, as does the
linux mmap(2) implementation by virtue of automatically rounding up for
the caller.

To avoid breaking legacy userspace relax the newly introduced fix.

Signed-off-by: Tvrtko Ursulin <[email protected]>
Fixes: 5c4604e757ba ("drm/i915: Prevent a race during I915_GEM_MMAP ioctl with 
WC set")
Reported-by: Guenter Roeck <[email protected]>
Cc: Adam Zabrocki <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Cc: <[email protected]> # v4.0+
Cc: Akash Goel <[email protected]>
Cc: Chris Wilson <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: [email protected]
Reviewed-by: Chris Wilson <[email protected]>
Link: 
https://patchwork.freedesktop.org/patch/msgid/[email protected]
(cherry picked from commit a90e1948efb648f567444f87f3c19b2a0787affd)
Signed-off-by: Rodrigo Vivi <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 drivers/gpu/drm/i915/i915_gem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 280c851714e6..03cda197fb6b 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1828,7 +1828,8 @@ __vma_matches(struct vm_area_struct *vma, struct file 
*filp,
        if (vma->vm_file != filp)
                return false;
 
-       return vma->vm_start == addr && (vma->vm_end - vma->vm_start) == size;
+       return vma->vm_start == addr &&
+              (vma->vm_end - vma->vm_start) == PAGE_ALIGN(size);
 }
 
 /**
-- 
2.19.1



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