Re: [PATCH] drivers: net: xgene: Simplify xgene_enet_setup_mss() to kill warning

[Iyappan Subramanian]

On Fri, Feb 24, 2017 at 2:30 AM, Geert Uytterhoeven
 wrote:
> With gcc-4.1.2 and -Os:
>
> drivers/net/ethernet/apm/xgene/xgene_enet_main.c: In function 
> ‘xgene_enet_start_xmit’:
> drivers/net/ethernet/apm/xgene/xgene_enet_main.c:297: warning: 
> ‘mss_index’ may be used uninitialized in this function
>
> Using a separate variable to track success may confuse the compiler.
> Preinitialize mss_index with -EBUSY and check for negative error values
> instead to kill the warning.
>
> Signed-off-by: Geert Uytterhoeven 
> ---
> Compile-tested only.
>
>  drivers/net/ethernet/apm/xgene/xgene_enet_main.c | 13 +++--
>  1 file changed, 3 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c 
> b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
> index d0d0d12b531fc683..e536301acfdec9fd 100644
> --- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
> +++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
> @@ -293,36 +293,29 @@ static int xgene_enet_tx_completion(struct 
> xgene_enet_desc_ring *cp_ring,
>  static int xgene_enet_setup_mss(struct net_device *ndev, u32 mss)
>  {
> struct xgene_enet_pdata *pdata = netdev_priv(ndev);
> -   bool mss_index_found = false;
> -   int mss_index;
> +   int mss_index = -EBUSY;
> int i;
>
> spin_lock(>mss_lock);
>
> /* Reuse the slot if MSS matches */
> -   for (i = 0; !mss_index_found && i < NUM_MSS_REG; i++) {
> +   for (i = 0; mss_index < 0 && i < NUM_MSS_REG; i++) {
> if (pdata->mss[i] == mss) {
> pdata->mss_refcnt[i]++;
> mss_index = i;
> -   mss_index_found = true;
> }
> }
>
> /* Overwrite the slot with ref_count = 0 */
> -   for (i = 0; !mss_index_found && i < NUM_MSS_REG; i++) {
> +   for (i = 0; mss_index < 0 && i < NUM_MSS_REG; i++) {
> if (!pdata->mss_refcnt[i]) {
> pdata->mss_refcnt[i]++;
> pdata->mac_ops->set_mss(pdata, mss, i);
> pdata->mss[i] = mss;
> mss_index = i;
> -   mss_index_found = true;
> }
> }
>
> -   /* No slots with ref_count = 0 available, return busy */
> -   if (!mss_index_found)
> -   mss_index = -EBUSY;
> -
> spin_unlock(>mss_lock);
>
> return mss_index;
> --
> 2.7.4
>

Thanks.

Acked-by: Iyappan Subramanian 

Re: [PATCH] drivers: net: xgene: Simplify xgene_enet_setup_mss() to kill warning

[David Miller]

From: Geert Uytterhoeven 
Date: Fri, 24 Feb 2017 11:30:03 +0100

> With gcc-4.1.2 and -Os:
> 
> drivers/net/ethernet/apm/xgene/xgene_enet_main.c: In function 
> ‘xgene_enet_start_xmit’:
> drivers/net/ethernet/apm/xgene/xgene_enet_main.c:297: warning: 
> ‘mss_index’ may be used uninitialized in this function
> 
> Using a separate variable to track success may confuse the compiler.
> Preinitialize mss_index with -EBUSY and check for negative error values
> instead to kill the warning.
> 
> Signed-off-by: Geert Uytterhoeven 

Applied, thank you.

[PATCH] drivers: net: xgene: Simplify xgene_enet_setup_mss() to kill warning

[Geert Uytterhoeven]

With gcc-4.1.2 and -Os:

drivers/net/ethernet/apm/xgene/xgene_enet_main.c: In function 
‘xgene_enet_start_xmit’:
drivers/net/ethernet/apm/xgene/xgene_enet_main.c:297: warning: ‘mss_index’ 
may be used uninitialized in this function

Using a separate variable to track success may confuse the compiler.
Preinitialize mss_index with -EBUSY and check for negative error values
instead to kill the warning.

Signed-off-by: Geert Uytterhoeven 
---
Compile-tested only.

 drivers/net/ethernet/apm/xgene/xgene_enet_main.c | 13 +++--
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c 
b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
index d0d0d12b531fc683..e536301acfdec9fd 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
@@ -293,36 +293,29 @@ static int xgene_enet_tx_completion(struct 
xgene_enet_desc_ring *cp_ring,
 static int xgene_enet_setup_mss(struct net_device *ndev, u32 mss)
 {
struct xgene_enet_pdata *pdata = netdev_priv(ndev);
-   bool mss_index_found = false;
-   int mss_index;
+   int mss_index = -EBUSY;
int i;
 
spin_lock(>mss_lock);
 
/* Reuse the slot if MSS matches */
-   for (i = 0; !mss_index_found && i < NUM_MSS_REG; i++) {
+   for (i = 0; mss_index < 0 && i < NUM_MSS_REG; i++) {
if (pdata->mss[i] == mss) {
pdata->mss_refcnt[i]++;
mss_index = i;
-   mss_index_found = true;
}
}
 
/* Overwrite the slot with ref_count = 0 */
-   for (i = 0; !mss_index_found && i < NUM_MSS_REG; i++) {
+   for (i = 0; mss_index < 0 && i < NUM_MSS_REG; i++) {
if (!pdata->mss_refcnt[i]) {
pdata->mss_refcnt[i]++;
pdata->mac_ops->set_mss(pdata, mss, i);
pdata->mss[i] = mss;
mss_index = i;
-   mss_index_found = true;
}
}
 
-   /* No slots with ref_count = 0 available, return busy */
-   if (!mss_index_found)
-   mss_index = -EBUSY;
-
spin_unlock(>mss_lock);
 
return mss_index;
-- 
2.7.4