[PATCH bpf-next] bpf: Remove unnecessary cpu == 0 check in memalloc

[PATCH bpf-next] bpf: Remove unnecessary cpu == 0 check in memalloc

[Yonghong Song]

After merging the patch set [1] to reduce memory usage
for bpf_global_percpu_ma, Alexei found a redundant check (cpu == 0)
in function bpf_mem_alloc_percpu_unit_init() ([2]).
Indeed, the check is unnecessary since c->unit_size will
be all NULL or all non-NULL for all cpus before
for_each_possible_cpu() loop.
Removing the check makes code less confusing.

  [1] https://lore.kernel.org/all/20231222031729.1287957-1-yonghong.song@linux.dev/
  [2] https://lore.kernel.org/all/20231222031745.1289082-1-yonghong.song@linux.dev/

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
 kernel/bpf/memalloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
index 460c8f38fed6..550f02e2cb13 100644
--- a/kernel/bpf/memalloc.c
+++ b/kernel/bpf/memalloc.c
@@ -613,7 +613,7 @@ int bpf_mem_alloc_percpu_unit_init(struct bpf_mem_alloc *ma, int size)
 	for_each_possible_cpu(cpu) {
 		cc = per_cpu_ptr(pcc, cpu);
 		c = &cc->cache[i];
-		if (cpu == 0 && c->unit_size)
+		if (c->unit_size)
 			break;
 
 		c->unit_size = unit_size;
-- 
2.34.1

Re: [PATCH bpf-next] bpf: Remove unnecessary cpu == 0 check in memalloc

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Thu,  4 Jan 2024 08:57:44 -0800 you wrote:
> After merging the patch set [1] to reduce memory usage
> for bpf_global_percpu_ma, Alexei found a redundant check (cpu == 0)
> in function bpf_mem_alloc_percpu_unit_init() ([2]).
> Indeed, the check is unnecessary since c->unit_size will
> be all NULL or all non-NULL for all cpus before
> for_each_possible_cpu() loop.
> Removing the check makes code less confusing.
> 
> [...]

Here is the summary with links:
  - [bpf-next] bpf: Remove unnecessary cpu == 0 check in memalloc
    https://git.kernel.org/bpf/bpf-next/c/9ddf872b47e3

You are awesome, thank you!
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