From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1E5EB4F392D; Thu, 17 Sep 2026 16:00:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660854; cv=none; b=JBEDk1fzyQ5dUEcuMqCqnjD+bFN58IZn5YAah/f7tSYX2o0zPRCLXZXJQ35IJHIHpYMi4rNQHf1UDElQ1Jkcv3OBLeJx6FgSVRGwUpYaVllTQDqsAyBt59Kgy1XvFeIkBi/fiXP8D/dHVYOpdRlJg7MV+qylYqZ+dCGyTEAboL0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660854; c=relaxed/simple; bh=Cl18hntfLuSHMEm7E5vPMWAcrfXydLquZ+3QBBNmMwE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GkZzHKT+FDNF6l1WFXWrxvmpfjp5JNo4Md4aBevsFAMAM6weG2F2KRX5D7olrVAf0qOyySgqNKN9FcC4nhdhcqiwswpePhMoW27Ffza9GY8WOOXAYxGlfrS+9ilvfxyUgONsfxrD4qIisZIDHo7nRArmGPOojXlBn5Fnu25++0g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2lRPCt3o; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2lRPCt3o" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E29C1F000FF; Thu, 17 Sep 2026 16:00:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789660852; bh=a+XEMmBW7CWRhTLmZQD7/Y/RXyq1+lh1nhwZ8e568Iw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=2lRPCt3oNfJ6RlCkhQxZSr5IpObw4hw4byZXwm0juHF4R3FuIJSXSX6rurF38Gfqt 4imd96AHMHJWq7SgPMNKjKR4+X3neWLJO8y76Sh3JOr8qJcmqDXOxzXuVn1XZaaqgV KtJ2mnPMhXTK/Y7qbE6xi/mDzmqyT36IcsfeVVPo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Thomas Richter , Sumanth Korikkar , Heiko Carstens , Vasily Gorbik , Sasha Levin Subject: [PATCH 7.2 729/733] s390/pai: Move locking to event init and delete Date: Thu, 17 Sep 2026 16:17:17 +0100 Message-ID: <20260917151411.151520318@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Richter [ Upstream commit e8df39dacb7d98d2b2aea431ca652d9fadf5efa3 ] Move mutex locking from per CPU allocation to event allocation. No functional change. Signed-off-by: Thomas Richter Reviewed-by: Sumanth Korikkar Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik Stable-dep-of: 9ecc4d033879 ("s390/pai: Support CPU hotplug for PMU PAI") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/perf_pai.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) --- a/arch/s390/kernel/perf_pai.c +++ b/arch/s390/kernel/perf_pai.c @@ -138,21 +138,19 @@ static void pai_free(struct pai_mapptr * } /* Adjust usage counters and remove allocated memory when all users are - * gone. + * gone. Called under mutex_lock. */ static void pai_event_destroy_cpu(int idx, int cpu) { struct pai_mapptr *mp = per_cpu_ptr(pai_root[idx].mapptr, cpu); struct pai_map *cpump = mp->mapptr; - mutex_lock(&pai_reserve_mutex); debug_sprintf_event(paidbg, 5, "%s users %d refcnt %u\n", __func__, cpump->active_events, refcount_read(&cpump->refcnt)); if (refcount_dec_and_test(&cpump->refcnt)) pai_free(mp); pai_root_free(idx); - mutex_unlock(&pai_reserve_mutex); } static void pai_event_destroy(struct perf_event *event) @@ -160,6 +158,7 @@ static void pai_event_destroy(struct per int cpu = 0, idx = PAI_PMU_IDX(event); free_page(PAI_SAVE_AREA(event)); + mutex_lock(&pai_reserve_mutex); if (event->cpu == -1) { struct cpumask *mask = PAI_CPU_MASK(event); @@ -169,6 +168,7 @@ static void pai_event_destroy(struct per } else { pai_event_destroy_cpu(idx, event->cpu); } + mutex_unlock(&pai_reserve_mutex); } static void paicrypt_event_destroy(struct perf_event *event) @@ -232,12 +232,10 @@ static u64 paicrypt_getall(struct perf_e return sum; } -/* Check concurrent access of counting and sampling for crypto events. - * This function is called in process context and it is save to block. - * When the event initialization functions fails, no other call back will - * be invoked. - * - * Allocate the memory for the event. +/* Allocate all per-CPU data structures. This function is called in + * process context and can block. In case of error all partly allocated + * memory is released and the reference counters adjusted correctly. + * Called under mutex_lock. */ static int pai_alloc_cpu(int idx, int cpu) { @@ -246,11 +244,10 @@ static int pai_alloc_cpu(int idx, int cp struct pai_mapptr *mp; int rc; - mutex_lock(&pai_reserve_mutex); /* Allocate root node */ rc = pai_root_alloc(idx); if (rc) - goto unlock; + goto out; /* Allocate node for this event */ mp = per_cpu_ptr(pai_root[idx].mapptr, cpu); @@ -308,12 +305,12 @@ undo: */ pai_root_free(idx); } -unlock: - mutex_unlock(&pai_reserve_mutex); +out: /* If rc is non-zero, no increment of counter/sampler was done. */ return rc; } +/* Called under mutex_lock */ static int pai_alloc(struct perf_event *event) { int idx = PAI_PMU_IDX(event); @@ -390,10 +387,12 @@ static int pai_event_init(struct perf_ev } } + mutex_lock(&pai_reserve_mutex); if (event->cpu >= 0) rc = pai_alloc_cpu(idx, event->cpu); else rc = pai_alloc(event); + mutex_unlock(&pai_reserve_mutex); if (rc) { free_page(PAI_SAVE_AREA(event)); goto out;