| Message ID | 20190307162101.29204-1-natechancellor@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | net: stmmac: Avoid sometimes uninitialized Clang warnings | expand |
From: Nathan Chancellor <natechancellor@gmail.com> Date: Thu, 7 Mar 2019 09:21:01 -0700 > @@ -565,7 +565,7 @@ static int stmmac_hwtstamp_set(struct net_device *dev, struct ifreq *ifr) > u32 ts_master_en = 0; > u32 ts_event_en = 0; > u32 value = 0; > - u32 sec_inc; > + u32 sec_inc = 0; > bool xmac; Please don't break the reverse christmas tree ordering here, thank you.
On Thu, Mar 7, 2019 at 9:49 AM David Miller <davem@davemloft.net> wrote: > > From: Nathan Chancellor <natechancellor@gmail.com> > Date: Thu, 7 Mar 2019 09:21:01 -0700 > > > @@ -565,7 +565,7 @@ static int stmmac_hwtstamp_set(struct net_device *dev, struct ifreq *ifr) > > u32 ts_master_en = 0; > > u32 ts_event_en = 0; > > u32 value = 0; > > - u32 sec_inc; > > + u32 sec_inc = 0; > > bool xmac; > > Please don't break the reverse christmas tree ordering here, thank you. Every codebase has its own unique code style. *wonders how clang-format could or could not handle that rule* Thanks for sending the patch Nathan; if you could resend with the declaration order changed so that the line width decreases going down in the order, you can add my Reviewed-by tag.
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index e2a13ec2e30b..001a45aed273 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -480,7 +480,7 @@ static void stmmac_get_tx_hwtstamp(struct stmmac_priv *priv, struct dma_desc *p, struct sk_buff *skb) { struct skb_shared_hwtstamps shhwtstamp; - u64 ns; + u64 ns = 0; if (!priv->hwts_tx_en) return; @@ -519,7 +519,7 @@ static void stmmac_get_rx_hwtstamp(struct stmmac_priv *priv, struct dma_desc *p, { struct skb_shared_hwtstamps *shhwtstamp = NULL; struct dma_desc *desc = p; - u64 ns; + u64 ns = 0; if (!priv->hwts_rx_en) return; @@ -565,7 +565,7 @@ static int stmmac_hwtstamp_set(struct net_device *dev, struct ifreq *ifr) u32 ts_master_en = 0; u32 ts_event_en = 0; u32 value = 0; - u32 sec_inc; + u32 sec_inc = 0; bool xmac; xmac = priv->plat->has_gmac4 || priv->plat->has_xgmac;
When building with -Wsometimes-uninitialized, Clang warns: drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:495:3: warning: variable 'ns' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:495:3: warning: variable 'ns' is used uninitialized whenever '&&' condition is false [-Wsometimes-uninitialized] drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:532:3: warning: variable 'ns' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:532:3: warning: variable 'ns' is used uninitialized whenever '&&' condition is false [-Wsometimes-uninitialized] drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:741:3: warning: variable 'sec_inc' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:741:3: warning: variable 'sec_inc' is used uninitialized whenever '&&' condition is false [-Wsometimes-uninitialized] Clang is concerned with the use of stmmac_do_void_callback (which stmmac_get_timestamp and stmmac_config_sub_second_increment wrap), as it may fail to initialize these values if the if condition was ever false (meaning the callbacks don't exist). It's not wrong because the callbacks (get_timestamp and config_sub_second_increment respectively) are the ones that initialize the variables. While it's unlikely that the callbacks are ever going to disappear and make that condition false, we can easily avoid this warning by zero initialize the variables. Link: https://github.com/ClangBuiltLinux/linux/issues/384 Suggested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)