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bh=WQfGLRATu5yNqviGHfeBkCPNz4Cl1WILm/qvutnMXWM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dmjUVyzkqRGC4Yojq0nM+pzKAoFDXDU3sVCdhZ3hv2uEK5wjYbcmA3aTqHR+GuGh4 uEct+GTMJZbVjpj5FAlkfhw1EVUoO7XvwA0m1qaNQOkDbawzVhGrZfU9wkL/e3A2Nl jOGKt40oSlBMO2ZkGesT6jY+Mz6QSKGQEJ6kGbb8A2x8+10XVbMdhbJLYEWKWl3TgS EMSeGVNi9cZ3LvKM0rqDRcNRqrvXgcEbZU0UQehUPp2UDMFVE2XQWrl0HldWnRwgNO 1kyLYV2jiJv1yz9VGjAXR6a+zhEWjYF7P8pjnlnMW3k2DY9TWQKx94lB9ZUCVlVFYs CkenS7BaVQY0A== From: SeongJae Park To: akpm@linux-foundation.org Cc: SeongJae Park , vbabka@suse.cz, willy@infradead.org, paulmck@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 2/2] mm/slab: break up RCU readers on SLAB_TYPESAFE_BY_RCU example code Date: Mon, 17 Apr 2023 19:04:50 +0000 Message-Id: <20230417190450.1682-3-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230417190450.1682-1-sj@kernel.org> References: <20230417190450.1682-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 600B6A0013 X-Stat-Signature: 88zqec5x9wk1daf1ak3d8u8ntxdp97nr X-Rspam-User: X-HE-Tag: 1681758297-870561 X-HE-Meta: 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 IQe4DeXD +CmOnBTwnJF7v36Mi8+XDsvI6E9fjaf5w70KPQpn1zAGuPOPvjlospSRkSN6795qAes1M4LQgEc0fYZ71LNcDIkJmD4G2aSZf7lLpeeSPqI/ipvy7+bxL/ln27NrapR12THQM84DS2ONhKb2k/ipVgxg9Bc8eUm5+HgztCHQ/ToRbvbQorboglBpxlfP0pj7ZJIoFveHaQzCHuZ05Q5fJlXkSSACML35YaUkO1XUfSO2KKDKXZSJAUgvHQTrdilvSUIwCosp9evBP0Y3c2dnKEWH42jUcL8o4/QuHoob7kniwPnXpyonTEh2vA9ipodYxrGzNbkLa9btSShfecThQWNIocdv8H9jkEJbHHNPleo1ebDch8OxwwWvZOe0BHRkY36PaL3Uioe+qjiq9KwrPZwdcsA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The SLAB_TYPESAFE_BY_RCU example code snippet uses a single RCU read-side critical section for retries. 'Documentation/RCU/rculist_nulls.rst' has similar example code snippet, and commit da82af04352b ("doc: Update and wordsmith rculist_nulls.rst") broke it up. Apply the change to SLAB_TYPESAFE_BY_RCU example code snippet, too. Signed-off-by: SeongJae Park --- include/linux/slab.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/include/linux/slab.h b/include/linux/slab.h index b18e56c6f06c..6acf1b7c6551 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -53,16 +53,18 @@ * stays valid, the trick to using this is relying on an independent * object validation pass. Something like: * + * begin: * rcu_read_lock(); - * again: * obj = lockless_lookup(key); * if (obj) { * if (!try_get_ref(obj)) // might fail for free objects - * goto again; + * rcu_read_unlock(); + * goto begin; * * if (obj->key != key) { // not the object we expected * put_ref(obj); - * goto again; + * rcu_read_unlock(); + * goto begin; * } * } * rcu_read_unlock(); -- 2.25.1