[Intel-gfx] [PATCH] drm/i915: Fix copy_to_user usage for pipe_crc

[Rodrigo Vivi]

Copy to user return the number of bytes it couldn't write
and zero on success. So any number different than 0 should
be considered a fault, not only when it doesn't write
the full size.

v2: fixed the inverted logic. (Ville)

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 7c42ec4..8557eb2 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -3632,7 +3632,6 @@ i915_pipe_crc_read(struct file *filep, char __user *user_buf, size_t count,
 	while (n_entries > 0) {
 		struct intel_pipe_crc_entry *entry =
 			&pipe_crc->entries[pipe_crc->tail];
-		int ret;
 
 		if (CIRC_CNT(pipe_crc->head, pipe_crc->tail,
 			     INTEL_PIPE_CRC_ENTRIES_NR) < 1)
@@ -3649,8 +3648,7 @@ i915_pipe_crc_read(struct file *filep, char __user *user_buf, size_t count,
 
 		spin_unlock_irq(&pipe_crc->lock);
 
-		ret = copy_to_user(user_buf, buf, PIPE_CRC_LINE_LEN);
-		if (ret == PIPE_CRC_LINE_LEN)
+		if (copy_to_user(user_buf, buf, PIPE_CRC_LINE_LEN))
 			return -EFAULT;
 
 		user_buf += PIPE_CRC_LINE_LEN;
-- 
2.5.5