netdev - [PATCH bpf-next 3/4] bpf: Don't do preempt check when migrate is disabled

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Date:   Wed, 29 Jun 2022 15:48:31 +0000
From:   Yafang Shao <laoar.shao@...il.com>
To:     ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
        kafai@...com, songliubraving@...com, yhs@...com,
        john.fastabend@...il.com, kpsingh@...nel.org, quentin@...valent.com
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        Yafang Shao <laoar.shao@...il.com>
Subject: [PATCH bpf-next 3/4] bpf: Don't do preempt check when migrate is disabled

It doesn't need to do the preempt check when migrate is disabled
after commit
74d862b682f5 ("sched: Make migrate_disable/enable() independent of RT").

Signed-off-by: Yafang Shao <laoar.shao@...il.com>
---
 kernel/bpf/bpf_task_storage.c | 8 ++++----
 kernel/bpf/hashtab.c          | 6 +++---
 kernel/bpf/trampoline.c       | 4 ++--
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c
index e9014dc62682..6f290623347e 100644
--- a/kernel/bpf/bpf_task_storage.c
+++ b/kernel/bpf/bpf_task_storage.c
@@ -26,20 +26,20 @@ static DEFINE_PER_CPU(int, bpf_task_storage_busy);
 static void bpf_task_storage_lock(void)
 {
 	migrate_disable();
-	__this_cpu_inc(bpf_task_storage_busy);
+	this_cpu_inc(bpf_task_storage_busy);
 }
 
 static void bpf_task_storage_unlock(void)
 {
-	__this_cpu_dec(bpf_task_storage_busy);
+	this_cpu_dec(bpf_task_storage_busy);
 	migrate_enable();
 }
 
 static bool bpf_task_storage_trylock(void)
 {
 	migrate_disable();
-	if (unlikely(__this_cpu_inc_return(bpf_task_storage_busy) != 1)) {
-		__this_cpu_dec(bpf_task_storage_busy);
+	if (unlikely(this_cpu_inc_return(bpf_task_storage_busy) != 1)) {
+		this_cpu_dec(bpf_task_storage_busy);
 		migrate_enable();
 		return false;
 	}
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 9d4559a1c032..6a3a95037aac 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -166,8 +166,8 @@ static inline int htab_lock_bucket(const struct bpf_htab *htab,
 	hash = hash & HASHTAB_MAP_LOCK_MASK;
 
 	migrate_disable();
-	if (unlikely(__this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) {
-		__this_cpu_dec(*(htab->map_locked[hash]));
+	if (unlikely(this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) {
+		this_cpu_dec(*(htab->map_locked[hash]));
 		migrate_enable();
 		return -EBUSY;
 	}
@@ -190,7 +190,7 @@ static inline void htab_unlock_bucket(const struct bpf_htab *htab,
 		raw_spin_unlock_irqrestore(&b->raw_lock, flags);
 	else
 		spin_unlock_irqrestore(&b->lock, flags);
-	__this_cpu_dec(*(htab->map_locked[hash]));
+	this_cpu_dec(*(htab->map_locked[hash]));
 	migrate_enable();
 }
 
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 93c7675f0c9e..f4486e54fdb3 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -585,7 +585,7 @@ u64 notrace __bpf_prog_enter(struct bpf_prog *prog, struct bpf_tramp_run_ctx *ru
 
 	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
 
-	if (unlikely(__this_cpu_inc_return(*(prog->active)) != 1)) {
+	if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) {
 		inc_misses_counter(prog);
 		return 0;
 	}
@@ -631,7 +631,7 @@ u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog, struct bpf_tramp_r
 	migrate_disable();
 	might_fault();
 
-	if (unlikely(__this_cpu_inc_return(*(prog->active)) != 1)) {
+	if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) {
 		inc_misses_counter(prog);
 		return 0;
 	}
-- 
2.17.1