[PATCH] net-sysfs: Slightly optimize 'xps_queue_show()'

The 'mask' bitmap is local to this function. So the non-atomic
'__set_bit()' can be used to save a few cycles.

Signed-off-by: Christophe JAILLET <redacted>
---
 net/core/net-sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 9c01c642cf9e..3be3f4a6add3 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c

@@ -1452,7 +1452,7 @@ static ssize_t xps_queue_show(struct net_device *dev, unsigned int index,
 
 		for (i = map->len; i--;) {
 			if (map->queues[i] == index) {
-				set_bit(j, mask);
+				__set_bit(j, mask);
 				break;
 			}
 		}

-- 
2.30.2

Hello:

This patch was applied to netdev/net-next.git (master)
by David S. Miller [off-list ref]:

On Sun, 21 Nov 2021 19:01:03 +0100 you wrote:

The 'mask' bitmap is local to this function. So the non-atomic
'__set_bit()' can be used to save a few cycles.

Signed-off-by: Christophe JAILLET <redacted>
---
 net/core/net-sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Here is the summary with links:
  - net-sysfs: Slightly optimize 'xps_queue_show()'
    https://git.kernel.org/netdev/net-next/c/08a7abf4aff1

You are awesome, thank you!
-- 
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On Sun, Nov 21, 2021 at 2:38 PM Christophe JAILLET
[off-list ref] wrote:

The similar optimization can seem to be done in br_vlan.c and br_if.c as well.

Le 22/11/2021 à 16:23, Xin Long a écrit :

On Sun, Nov 21, 2021 at 2:38 PM Christophe JAILLET
[off-list ref] wrote:

quoted

The 'mask' bitmap is local to this function. So the non-atomic
'__set_bit()' can be used to save a few cycles.

Signed-off-by: Christophe JAILLET <redacted>
---
  net/core/net-sysfs.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 9c01c642cf9e..3be3f4a6add3 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c

@@ -1452,7 +1452,7 @@ static ssize_t xps_queue_show(struct net_device *dev, unsigned int index,

                 for (i = map->len; i--;) {
                         if (map->queues[i] == index) {
-                               set_bit(j, mask);
+                               __set_bit(j, mask);
                                 break;
                         }
                 }
--

2.30.2

The similar optimization can seem to be done in br_vlan.c and br_if.c as well.

Hi,

br_if.c should be fixed in cc0be1ad686f.

br_vlan.c was not spotted by my heuristic (a set of grep, while looking 
at something else). So, thanks for your feedback.

Feel free to propose a patch for it, it was not part of my todo list :)

If you prefer, I can also send a patch. Let me know.

CJ