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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 30 May 2019 16:00:16 +0100 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp23033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x4UF0FfR23331128 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 30 May 2019 15:00:15 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2D16AB206B; Thu, 30 May 2019 15:00:15 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 18C8BB2085; Thu, 30 May 2019 15:00:15 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.216]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 30 May 2019 15:00:15 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id D523E16C5D84; Thu, 30 May 2019 08:00:16 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 3/9] rcu: Make kfree_rcu() ignore NULL pointers Date: Thu, 30 May 2019 08:00:09 -0700 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190530145942.GA30318@linux.ibm.com> References: <20190530145942.GA30318@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 19053015-0040-0000-0000-000004F68291 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011185; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000286; SDB=6.01210785; UDB=6.00636158; IPR=6.00991820; MB=3.00027120; MTD=3.00000008; XFM=3.00000015; UTC=2019-05-30 15:00:20 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19053015-0041-0000-0000-000009029CDE Message-Id: <20190530150015.30995-3-paulmck@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-05-30_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=13 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905300106 Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org This commit makes the kfree_rcu() macro's semantics be consistent with the likes of kfree() by adding a check for NULL pointers, so that kfree_rcu(NULL, ...) is a no-op. Reported-by: Andriy Shevchenko Reported-by: Christoph Hellwig Signed-off-by: Paul E. McKenney Reviewed-by: Andriy Shevchenko --- include/linux/rcupdate.h | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 922bb6848813..915460ec0872 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -805,7 +805,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) /** * kfree_rcu() - kfree an object after a grace period. * @ptr: pointer to kfree - * @rcu_head: the name of the struct rcu_head within the type of @ptr. + * @rhf: the name of the struct rcu_head within the type of @ptr. * * Many rcu callbacks functions just call kfree() on the base structure. * These functions are trivial, but their size adds up, and furthermore @@ -828,9 +828,13 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) * The BUILD_BUG_ON check must not involve any function calls, hence the * checks are done in macros here. */ -#define kfree_rcu(ptr, rcu_head) \ - __kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head)) - +#define kfree_rcu(ptr, rhf) \ +do { \ + typeof (ptr) ___p = (ptr); \ + \ + if (___p) \ + __kfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \ +} while (0) /* * Place this after a lock-acquisition primitive to guarantee that -- 2.17.1