From: Arnd Bergmann <[email protected]>
One local variable has become unused after a recent change:
drivers/net/ethernet/sfc/ef100_nic.c: In function 'ef100_probe_netdev_pf':
drivers/net/ethernet/sfc/ef100_nic.c:1155:21: error: unused variable 'net_dev' [-Werror=unused-variable]
struct net_device *net_dev = efx->net_dev;
^~~~~~~
The variable is still used in an #ifdef. Replace the #ifdef with
an if(IS_ENABLED()) check that lets the compiler see where it is
used, rather than adding another #ifdef.
This also fixes an uninitialized return value in ef100_probe_netdev_pf()
that gcc did not spot.
Fixes: 7e056e2360d9 ("sfc: obtain device mac address based on firmware handle for ef100")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/net/ethernet/sfc/ef100_nic.c | 27 ++++++++++-----------------
1 file changed, 10 insertions(+), 17 deletions(-)
diff --git a/drivers/net/ethernet/sfc/ef100_nic.c b/drivers/net/ethernet/sfc/ef100_nic.c
index becd21c2325d..4dc643b0d2db 100644
--- a/drivers/net/ethernet/sfc/ef100_nic.c
+++ b/drivers/net/ethernet/sfc/ef100_nic.c
@@ -399,14 +399,14 @@ static int ef100_filter_table_up(struct efx_nic *efx)
* filter insertion will need to take the lock for read.
*/
up_write(&efx->filter_sem);
-#ifdef CONFIG_SFC_SRIOV
- rc = efx_tc_insert_rep_filters(efx);
+ if (IS_ENABLED(CONFIG_SFC_SRIOV))
+ rc = efx_tc_insert_rep_filters(efx);
+
/* Rep filter failure is nonfatal */
if (rc)
netif_warn(efx, drv, efx->net_dev,
"Failed to insert representor filters, rc %d\n",
rc);
-#endif
return 0;
fail_vlan0:
@@ -419,9 +419,8 @@ static int ef100_filter_table_up(struct efx_nic *efx)
static void ef100_filter_table_down(struct efx_nic *efx)
{
-#ifdef CONFIG_SFC_SRIOV
- efx_tc_remove_rep_filters(efx);
-#endif
+ if (IS_ENABLED(CONFIG_SFC_SRIOV))
+ efx_tc_remove_rep_filters(efx);
down_write(&efx->filter_sem);
efx_mcdi_filter_del_vlan(efx, 0);
efx_mcdi_filter_del_vlan(efx, EFX_FILTER_VID_UNSPEC);
@@ -737,7 +736,6 @@ static unsigned int efx_ef100_recycle_ring_size(const struct efx_nic *efx)
return 10 * EFX_RECYCLE_RING_SIZE_10G;
}
-#ifdef CONFIG_SFC_SRIOV
static int efx_ef100_get_base_mport(struct efx_nic *efx)
{
struct ef100_nic_data *nic_data = efx->nic_data;
@@ -773,7 +771,6 @@ static int efx_ef100_get_base_mport(struct efx_nic *efx)
return 0;
}
-#endif
static int compare_versions(const char *a, const char *b)
{
@@ -1155,10 +1152,9 @@ int ef100_probe_netdev_pf(struct efx_nic *efx)
struct net_device *net_dev = efx->net_dev;
int rc;
- if (!nic_data->grp_mae)
+ if (!IS_ENABLED(CONFIG_SFC_SRIOV) || !nic_data->grp_mae)
return 0;
-#ifdef CONFIG_SFC_SRIOV
rc = efx_init_struct_tc(efx);
if (rc)
return rc;
@@ -1193,7 +1189,6 @@ int ef100_probe_netdev_pf(struct efx_nic *efx)
net_dev->features |= NETIF_F_HW_TC;
efx->fixed_features |= NETIF_F_HW_TC;
}
-#endif
return rc;
}
@@ -1206,12 +1201,11 @@ void ef100_remove(struct efx_nic *efx)
{
struct ef100_nic_data *nic_data = efx->nic_data;
-#ifdef CONFIG_SFC_SRIOV
- if (efx->mae) {
+ if (IS_ENABLED(CONFIG_SFC_SRIOV) && efx->mae) {
efx_ef100_fini_reps(efx);
efx_fini_mae(efx);
}
-#endif
+
efx_mcdi_detach(efx);
efx_mcdi_fini(efx);
if (nic_data)
@@ -1304,9 +1298,8 @@ const struct efx_nic_type ef100_pf_nic_type = {
.update_stats = ef100_update_stats,
.pull_stats = efx_mcdi_mac_pull_stats,
.stop_stats = efx_mcdi_mac_stop_stats,
-#ifdef CONFIG_SFC_SRIOV
- .sriov_configure = efx_ef100_sriov_configure,
-#endif
+ .sriov_configure = IS_ENABLED(CONFIG_SFC_SRIOV) ?
+ efx_ef100_sriov_configure : NULL,
/* Per-type bar/size configuration not used on ef100. Location of
* registers is defined by extended capabilities.
--
2.39.1
On 17/02/2023 09:56, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> One local variable has become unused after a recent change:
>
> drivers/net/ethernet/sfc/ef100_nic.c: In function 'ef100_probe_netdev_pf':
> drivers/net/ethernet/sfc/ef100_nic.c:1155:21: error: unused variable 'net_dev' [-Werror=unused-variable]
> struct net_device *net_dev = efx->net_dev;
> ^~~~~~~
>
> The variable is still used in an #ifdef. Replace the #ifdef with
> an if(IS_ENABLED()) check that lets the compiler see where it is
> used, rather than adding another #ifdef.
So we've had Leon telling us[1] to use __maybe_unused, and you're
saying to use IS_ENABLED() instead. Which is right?
(And does it make any difference to build time? I'm assuming the
compiler is smart enough that this change doesn't affect text
size...?)
-ed
[1]: https://lore.kernel.org/netdev/[email protected]/T/#md2ecc82f18c200391dc6581ff68ff08eee9a65cf
On Fri, Feb 17, 2023, at 17:13, Edward Cree wrote:
> On 17/02/2023 09:56, Arnd Bergmann wrote:
>> From: Arnd Bergmann <[email protected]>
>>
>> One local variable has become unused after a recent change:
>>
>> drivers/net/ethernet/sfc/ef100_nic.c: In function 'ef100_probe_netdev_pf':
>> drivers/net/ethernet/sfc/ef100_nic.c:1155:21: error: unused variable 'net_dev' [-Werror=unused-variable]
>> struct net_device *net_dev = efx->net_dev;
>> ^~~~~~~
>>
>> The variable is still used in an #ifdef. Replace the #ifdef with
>> an if(IS_ENABLED()) check that lets the compiler see where it is
>> used, rather than adding another #ifdef.
>
> So we've had Leon telling us[1] to use __maybe_unused, and you're
> saying to use IS_ENABLED() instead. Which is right?
> (And does it make any difference to build time? I'm assuming the
> compiler is smart enough that this change doesn't affect text
> size...?)
> -ed
Both are correct, but I prefer the IS_ENABLED() change because it
improves build coverage. The resulting object code should be the
same, as the dead-code-elimination in gcc takes care of removing
it the same way.
If you use the __maybe_uninitialized annotation, you still need
an extra fix to initialize the ef100_probe_netdev_pf() return
code.
Arnd
On Fri, Feb 17, 2023 at 04:13:59PM +0000, Edward Cree wrote:
> On 17/02/2023 09:56, Arnd Bergmann wrote:
> > From: Arnd Bergmann <[email protected]>
> >
> > One local variable has become unused after a recent change:
> >
> > drivers/net/ethernet/sfc/ef100_nic.c: In function 'ef100_probe_netdev_pf':
> > drivers/net/ethernet/sfc/ef100_nic.c:1155:21: error: unused variable 'net_dev' [-Werror=unused-variable]
> > struct net_device *net_dev = efx->net_dev;
> > ^~~~~~~
> >
> > The variable is still used in an #ifdef. Replace the #ifdef with
> > an if(IS_ENABLED()) check that lets the compiler see where it is
> > used, rather than adding another #ifdef.
>
> So we've had Leon telling us[1] to use __maybe_unused, and you're
> saying to use IS_ENABLED() instead. Which is right?
> (And does it make any difference to build time? I'm assuming the
> compiler is smart enough that this change doesn't affect text
> size...?)
You are mixing answers, __maybe_unused is for variables. For functions,
it will be much saner to create empty declarations for relevant
functions in tc.h, for !CONFIG_SFC_SRIOV flow.
It will be much cleaner than spaghetti code in .c files which you have now.
Thanks
> -ed
>
> [1]: https://lore.kernel.org/netdev/[email protected]/T/#md2ecc82f18c200391dc6581ff68ff08eee9a65cf
On Fri, Feb 17, 2023 at 05:19:26PM +0100, Arnd Bergmann wrote:
> On Fri, Feb 17, 2023, at 17:13, Edward Cree wrote:
> > On 17/02/2023 09:56, Arnd Bergmann wrote:
> >> From: Arnd Bergmann <[email protected]>
> >>
> >> One local variable has become unused after a recent change:
> >>
> >> drivers/net/ethernet/sfc/ef100_nic.c: In function 'ef100_probe_netdev_pf':
> >> drivers/net/ethernet/sfc/ef100_nic.c:1155:21: error: unused variable 'net_dev' [-Werror=unused-variable]
> >> struct net_device *net_dev = efx->net_dev;
> >> ^~~~~~~
> >>
> >> The variable is still used in an #ifdef. Replace the #ifdef with
> >> an if(IS_ENABLED()) check that lets the compiler see where it is
> >> used, rather than adding another #ifdef.
> >
> > So we've had Leon telling us[1] to use __maybe_unused, and you're
> > saying to use IS_ENABLED() instead. Which is right?
> > (And does it make any difference to build time? I'm assuming the
> > compiler is smart enough that this change doesn't affect text
> > size...?)
> > -ed
>
> Both are correct, but I prefer the IS_ENABLED() change because it
> improves build coverage. The resulting object code should be the
> same, as the dead-code-elimination in gcc takes care of removing
> it the same way.
>
> If you use the __maybe_uninitialized annotation, you still need
> an extra fix to initialize the ef100_probe_netdev_pf() return
> code.
FWIIW, IS_ENABLED() is the approach that is more familiar to me.
Though I have nothing in particular against other approaches.
Questions of consistency aside, this patch does look good to
me and does appear to address the build problem in question - on x86_64.
Reviewed-by: Simon Horman <[email protected]>
Hello:
This patch was applied to netdev/net-next.git (master)
by David S. Miller <[email protected]>:
On Fri, 17 Feb 2023 10:56:39 +0100 you wrote:
> From: Arnd Bergmann <[email protected]>
>
> One local variable has become unused after a recent change:
>
> drivers/net/ethernet/sfc/ef100_nic.c: In function 'ef100_probe_netdev_pf':
> drivers/net/ethernet/sfc/ef100_nic.c:1155:21: error: unused variable 'net_dev' [-Werror=unused-variable]
> struct net_device *net_dev = efx->net_dev;
> ^~~~~~~
>
> [...]
Here is the summary with links:
- sfc: use IS_ENABLED() checks for CONFIG_SFC_SRIOV
https://git.kernel.org/netdev/net-next/c/a59f832a71c9
You are awesome, thank you!
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