netdev - [PATCH bpf-next 16/19] bpf: Remove migrate_{disable|enable} from bpf_selem

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Message-Id: <20250106081900.1665573-17-houtao@huaweicloud.com>
Date: Mon,  6 Jan 2025 16:18:57 +0800
From: Hou Tao <houtao@...weicloud.com>
To: bpf@...r.kernel.org,
	netdev@...r.kernel.org
Cc: Martin KaFai Lau <martin.lau@...ux.dev>,
	Alexei Starovoitov <alexei.starovoitov@...il.com>,
	Andrii Nakryiko <andrii@...nel.org>,
	Eduard Zingerman <eddyz87@...il.com>,
	Song Liu <song@...nel.org>,
	Hao Luo <haoluo@...gle.com>,
	Yonghong Song <yonghong.song@...ux.dev>,
	Daniel Borkmann <daniel@...earbox.net>,
	KP Singh <kpsingh@...nel.org>,
	Stanislav Fomichev <sdf@...ichev.me>,
	Jiri Olsa <jolsa@...nel.org>,
	John Fastabend <john.fastabend@...il.com>,
	houtao1@...wei.com,
	xukuohai@...wei.com
Subject: [PATCH bpf-next 16/19] bpf: Remove migrate_{disable|enable} from bpf_selem_alloc()

From: Hou Tao <houtao1@...wei.com>

bpf_selem_alloc() has two callers:
(1) bpf_sk_storage_clone_elem()
bpf_sk_storage_clone() has already disabled migration before invoking
bpf_sk_storage_clone_elem().

(2) bpf_local_storage_update()
Its callers include: cgrp/task/inode/sock storage ->map_update_elem()
callbacks and bpf_{cgrp|task|inode|sk}_storage_get() helpers. These
running contexts have already disabled migration

Therefore, there is no need to add extra migrate_{disable|enable} pair
in bpf_selem_alloc(). Also add a cant_migrate() check in
bpf_selem_alloc().

Signed-off-by: Hou Tao <houtao1@...wei.com>
---
 kernel/bpf/bpf_local_storage.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 12cf6382175e..fd48a2a17ccd 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -80,10 +80,10 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner,
 	if (charge_mem && mem_charge(smap, owner, smap->elem_size))
 		return NULL;
 
+	cant_migrate();
+
 	if (smap->bpf_ma) {
-		migrate_disable();
 		selem = bpf_mem_cache_alloc_flags(&smap->selem_ma, gfp_flags);
-		migrate_enable();
 		if (selem)
 			/* Keep the original bpf_map_kzalloc behavior
 			 * before started using the bpf_mem_cache_alloc.
-- 
2.29.2