From: Borislav Petkov <bp@alien8.de>
To: Justin He <Justin.He@arm.com>
Cc: Len Brown <lenb@kernel.org>, James Morse <James.Morse@arm.com>,
Tony Luck <tony.luck@intel.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Robert Richter <rric@kernel.org>,
Robert Moore <robert.moore@intel.com>,
Qiuxu Zhuo <qiuxu.zhuo@intel.com>,
Yazen Ghannam <yazen.ghannam@amd.com>,
Jan Luebbe <jlu@pengutronix.de>,
Khuong Dinh <khuong@os.amperecomputing.com>,
Kani Toshi <toshi.kani@hpe.com>, Ard Biesheuvel <ardb@kernel.org>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>,
"devel@acpica.org" <devel@acpica.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Shuai Xue <xueshuai@linux.alibaba.com>,
Jarkko Sakkinen <jarkko@kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
nd <nd@arm.com>, kernel test robot <lkp@intel.com>
Subject: Re: [PATCH v8 6/7] apei/ghes: Use unrcu_pointer for cmpxchg
Date: Tue, 11 Oct 2022 16:45:38 +0200 [thread overview]
Message-ID: <Y0WBklS1XpB5as+m@zn.tnic> (raw)
In-Reply-To: <DBBPR08MB4538A9F831FA96545BA35D9FF7239@DBBPR08MB4538.eurprd08.prod.outlook.com>
On Tue, Oct 11, 2022 at 02:32:48PM +0000, Justin He wrote:
> My original purpose is to make it pass the sparse checking.
Then do this pls.
This is a combined diff - do a second patch which does only remove the
smp_wmb(). The smp_wmb() there is not needed as the cmpxchg() already
implies a smp_mb() so there's no need for that separate, explicit one.
But it would be prudent to have it in a separate patch just in case.
Thx.
---
diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 85acfc589fb7..fd285bf8d114 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -154,7 +154,7 @@ struct ghes_vendor_record_entry {
static struct gen_pool *ghes_estatus_pool;
static unsigned long ghes_estatus_pool_size_request;
-static struct ghes_estatus_cache *ghes_estatus_caches[GHES_ESTATUS_CACHES_SIZE];
+static struct ghes_estatus_cache __rcu *ghes_estatus_caches[GHES_ESTATUS_CACHES_SIZE];
static atomic_t ghes_estatus_cache_alloced;
static int ghes_panic_timeout __read_mostly = 30;
@@ -842,9 +842,7 @@ static void ghes_estatus_cache_add(
slot_cache = cache;
}
}
- /* new_cache must be put into array after its contents are written */
- smp_wmb();
- if (slot != -1 && cmpxchg(ghes_estatus_caches + slot,
+ if (slot != -1 && cmpxchg((struct ghes_estatus_cache ** __force)(ghes_estatus_caches + slot),
slot_cache, new_cache) == slot_cache) {
if (slot_cache)
call_rcu(&slot_cache->rcu, ghes_estatus_cache_rcu_free);
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-10-11 14:45 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-10 2:35 [PATCH v8 0/7] Make ghes_edac a proper module Jia He
2022-10-10 2:35 ` [PATCH v8 1/7] efi/cper: export several helpers for ghes_edac to use Jia He
2022-10-10 2:35 ` [PATCH v8 2/7] EDAC/ghes: Add a notifier for reporting memory errors Jia He
2022-10-10 2:35 ` [PATCH v8 3/7] EDAC/ghes: Prepare to make ghes_edac a proper module Jia He
2022-10-10 2:35 ` [PATCH v8 4/7] EDAC/ghes: Make ghes_edac a proper module to remove the dependency on ghes Jia He
2022-10-10 2:35 ` [PATCH v8 5/7] EDAC: Add the ghes_get_devices() check for chipset-specific edac drivers Jia He
2022-10-10 2:35 ` [PATCH v8 6/7] apei/ghes: Use unrcu_pointer for cmpxchg Jia He
2022-10-11 10:33 ` Borislav Petkov
2022-10-11 14:32 ` Justin He
2022-10-11 14:45 ` Borislav Petkov [this message]
2022-10-12 4:35 ` Justin He
2022-10-12 12:04 ` Justin He
2022-10-13 13:37 ` Borislav Petkov
2022-10-13 15:41 ` Ard Biesheuvel
2022-10-13 16:37 ` Borislav Petkov
2022-10-13 16:45 ` Peter Zijlstra
2022-10-13 17:42 ` Borislav Petkov
2022-10-14 9:40 ` Ard Biesheuvel
2022-10-14 19:40 ` Borislav Petkov
2022-10-14 12:00 ` Justin He
2022-10-14 14:31 ` Ard Biesheuvel
2022-10-14 15:10 ` Peter Zijlstra
2022-10-14 15:24 ` Ard Biesheuvel
2022-10-17 8:47 ` Justin He
2022-10-17 9:27 ` Ard Biesheuvel
2022-10-17 11:57 ` Justin He
2022-10-13 16:41 ` Peter Zijlstra
2022-10-10 2:35 ` [PATCH v8 7/7] EDAC/igen6: Return consistent errno when another edac driver is enabled Jia He
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