Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1538905 > unrolled thread

[PATCH net-next 3/3] net: xgene: avoid bogus maybe-uninitialized warning

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH net-next 3/3] net: xgene: avoid bogus maybe-uninitialized warning Arnd Bergmann <arnd@arndb.de> - 2016-12-08 23:00 +0100
    Re: [PATCH net-next 3/3] net: xgene: avoid bogus  maybe-uninitialized warning David Miller <davem@davemloft.net> - 2016-12-09 03:40 +0100

#1538905 — [PATCH net-next 3/3] net: xgene: avoid bogus maybe-uninitialized warning

In some configurations, gcc cannot trace the state of variables
across a spin_unlock() barrier, leading to a warning about
correct code:

xgene_enet_main.c: In function 'xgene_enet_start_xmit':
../../../phy/mdio-xgene.h:112:14: error: 'mss_index' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Here we can trivially move the assignment before that spin_unlock,
which reliably avoids the warning.

Fixes: e3978673f514 ("drivers: net: xgene: Fix MSS programming")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/ethernet/apm/xgene/xgene_enet_main.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
index 6c7eea8b36af..dba4b883e9a3 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
@@ -319,11 +319,11 @@ static int xgene_enet_setup_mss(struct net_device *ndev, u32 mss)
 		}
 	}
 
-	spin_unlock(&pdata->mss_lock);
-
 	/* No slots with ref_count = 0 available, return busy */
 	if (!mss_index_found)
-		return -EBUSY;
+		mss_index = -EBUSY;
+
+	spin_unlock(&pdata->mss_lock);
 
 	return mss_index;
 }
-- 
2.9.0

[toc] | [next] | [standalone]

#1539021 — Re: [PATCH net-next 3/3] net: xgene: avoid bogus maybe-uninitialized warning

From: Arnd Bergmann <arnd@arndb.de>
Date: Thu,  8 Dec 2016 22:57:05 +0100

> In some configurations, gcc cannot trace the state of variables
> across a spin_unlock() barrier, leading to a warning about
> correct code:
> 
> xgene_enet_main.c: In function 'xgene_enet_start_xmit':
> ../../../phy/mdio-xgene.h:112:14: error: 'mss_index' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> 
> Here we can trivially move the assignment before that spin_unlock,
> which reliably avoids the warning.
> 
> Fixes: e3978673f514 ("drivers: net: xgene: Fix MSS programming")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Applied.

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web