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Mon, 30 Jul 2018 07:16:56 +0000 (UTC) Delivered-To: dm-devel@redhat.com Received: from mx1.redhat.com (ext-mx20.extmail.prod.ext.phx2.redhat.com [10.5.110.49]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 131AC100164C; Mon, 30 Jul 2018 07:16:52 +0000 (UTC) Received: from sender-pp-092.zoho.com (sender-pp-092.zoho.com [135.84.80.237]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D0EEB3086267; Mon, 30 Jul 2018 07:16:50 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=zapps768; d=zoho.com; h=from:to:cc:subject:date:message-id:in-reply-to:references; b=O8ywsKPHA4QkEojT1tTHWNbf3U3VAyBfKC1kAzUgKxpbgtMOCnav/i1b4Lv7B7TRSEaWuAdOOvn1 Rhhh9yuuVinC417TmprZYzjw+ZLr3Bg2DuFb0z6VQQxzTnegsUWN Received: from YEHS1XR956R00D1.lenovo.com (221.219.122.69 [221.219.122.69]) by mx.zohomail.com with SMTPS id 153293498037231.188860816768056; Mon, 30 Jul 2018 00:16:20 -0700 (PDT) From: Huaisheng Ye To: linux-nvdimm@lists.01.org, dan.j.williams@intel.com Date: Mon, 30 Jul 2018 15:15:44 +0800 Message-Id: <20180730071548.9172-3-yehs2007@zoho.com> In-Reply-To: <20180730071548.9172-1-yehs2007@zoho.com> References: <20180730071548.9172-1-yehs2007@zoho.com> X-ZohoMailClient: External X-Greylist: Sender passed SPF test, Sender IP whitelisted by DNSRBL, ACL 209 matched, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Mon, 30 Jul 2018 07:16:51 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Mon, 30 Jul 2018 07:16:51 +0000 (UTC) for IP:'135.84.80.237' DOMAIN:'sender-pp-092.zoho.com' HELO:'sender-pp-092.zoho.com' FROM:'yehs2007@zoho.com' RCPT:'' X-RedHat-Spam-Score: 0.14 (DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE, SPF_PASS) 135.84.80.237 sender-pp-092.zoho.com 135.84.80.237 sender-pp-092.zoho.com X-Scanned-By: MIMEDefang 2.84 on 10.5.110.49 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-loop: dm-devel@redhat.com X-Mailman-Approved-At: Mon, 30 Jul 2018 04:28:49 -0400 Cc: jack@suse.cz, snitzer@redhat.com, heiko.carstens@de.ibm.com, dm-devel@redhat.com, agk@redhat.com, linux-s390@vger.kernel.org, dave.jiang@intel.com, Huaisheng Ye , vishal.l.verma@intel.com, willy@infradead.org, bart.vanassche@wdc.com, ross.zwisler@linux.intel.com, keescook@chromium.org, chengnt@lenovo.com, colyli@suse.de, schwidefsky@de.ibm.com, viro@zeniv.linux.org.uk, axboe@kernel.dk, martin.petersen@oracle.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [dm-devel] [PATCH v3 2/6] s390, dcssblk: kaddr and pfn can be NULL to ->direct_access() X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Mon, 30 Jul 2018 08:28:55 +0000 (UTC) X-Virus-Scanned: ClamAV using ClamSMTP From: Huaisheng Ye dcssblk_direct_access() needs to check the validity of pointers kaddr and pfn for NULL assignment. If anyone equals to NULL, it doesn't need to calculate the value. If either of them is equal to NULL, that is to say callers may have no need for kaddr or pfn, so this patch is prepared for allowing them to pass in NULL instead of having to pass in a pointer or local variable that they then just throw away. Signed-off-by: Huaisheng Ye Reviewed-by: Ross Zwisler Acked-by: Martin Schwidefsky --- drivers/s390/block/dcssblk.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index ed60728..23e526c 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -922,9 +922,11 @@ static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show, unsigned long dev_sz; dev_sz = dev_info->end - dev_info->start + 1; - *kaddr = (void *) dev_info->start + offset; - *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), - PFN_DEV|PFN_SPECIAL); + if (kaddr) + *kaddr = (void *) dev_info->start + offset; + if (pfn) + *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), + PFN_DEV|PFN_SPECIAL); return (dev_sz - offset) / PAGE_SIZE; }