net/fm10k/base: update comment regarding reserved bits check

The original comment may be read incorrectly as referring to checking
the *entire* length is zero. However, it merely checks only the reserved
bits of both length and reserved in a small amount of code. Update the
comment to indicate this is a clever trick and clearly spell out that it
only checks the reserve bits.

Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>

diff --git a/drivers/net/fm10k/base/fm10k_vf.c b/drivers/net/fm10k/base/fm10k_vf.c
index 533dfeb..dd3d318 100644 (file)
--- a/drivers/net/fm10k/base/fm10k_vf.c
+++ b/drivers/net/fm10k/base/fm10k_vf.c
@@ -225,7 +225,7 @@ STATIC s32 fm10k_update_vlan_vf(struct fm10k_hw *hw, u32 vid, u8 vsi, bool set)
        if (vsi)
                return FM10K_ERR_PARAM;
 
-       /* verify upper 4 bits of vid and length are 0 */
+       /* clever trick to verify reserved bits in both vid and length */
        if ((vid << 16 | vid) >> 28)
                return FM10K_ERR_PARAM;