[patch -mainline] fm10k: drop upper bits of VLAN ID

[patch -mainline] fm10k: drop upper bits of VLAN ID

[Dan Carpenter]

Static checkers complain that the shifts in "(vid << 4) >> 4" perfectly
cancel each other out and the code is a no-op.  "vid" is a u16.  The
comment says that the intention here is to drop the upper bits so I have
added a cast to "u16" to do that.

Fixes: 401b5383c6c9 ('fm10k: Add support for configuring PF interface')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Static analysis.  Not tested.

diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_pf.c b/drivers/net/ethernet/intel/fm10k/fm10k_pf.c
index 275423d..ee30d06 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_pf.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_pf.c
@@ -335,7 +335,7 @@ static s32 fm10k_update_xc_addr_pf(struct fm10k_hw *hw, u16 glort,
 		return FM10K_ERR_PARAM;
 
 	/* drop upper 4 bits of VLAN ID */
-	vid = (vid << 4) >> 4;
+	vid = (u16)(vid << 4) >> 4;
 
 	/* record fields */
 	mac_update.mac_lower = cpu_to_le32(((u32)mac[2] << 24) |

Re: [patch -mainline] fm10k: drop upper bits of VLAN ID

[Dan Carpenter]

On Fri, Jan 30, 2015 at 11:41:27AM +0300, Dan Carpenter wrote:
> Static checkers complain that the shifts in "(vid << 4) >> 4" perfectly
> cancel each other out and the code is a no-op.  "vid" is a u16.  The
> comment says that the intention here is to drop the upper bits so I have
> added a cast to "u16" to do that.
> 
> Fixes: 401b5383c6c9 ('fm10k: Add support for configuring PF interface')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Oh...  Rasmus Villemoes already fixed this.

regards,
dan carpenter


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Re: [patch -mainline] fm10k: drop upper bits of VLAN ID

[Vick, Matthew]

On 1/30/15, 2:50 AM, "Dan Carpenter" <dan.carpenter@oracle.com> wrote:

>On Fri, Jan 30, 2015 at 11:41:27AM +0300, Dan Carpenter wrote:
>> Static checkers complain that the shifts in "(vid << 4) >> 4" perfectly
>> cancel each other out and the code is a no-op.  "vid" is a u16.  The
>> comment says that the intention here is to drop the upper bits so I have
>> added a cast to "u16" to do that.
>> 
>> Fixes: 401b5383c6c9 ('fm10k: Add support for configuring PF interface')
>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
>Oh...  Rasmus Villemoes already fixed this.
>
>regards,
>dan carpenter

Yep, we have a patch coming through Jeff's tree now to resolve the issue
(technically my version of the patch, which doesn't try to mask off the
bits but instead rejects an out-of-bounds VLAN ID). Thanks, Dan!

Cheers,
Matthew


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