From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id C36F320988442 for ; Mon, 16 Jul 2018 10:11:33 -0700 (PDT) Subject: [PATCH v2 09/14] s390, dcssblk: Allow a NULL-pfn to ->direct_access() From: Dan Williams Date: Mon, 16 Jul 2018 10:01:08 -0700 Message-ID: <153176046886.12695.7487453664953251895.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <153176041838.12695.3365448145295112857.stgit@dwillia2-desk3.amr.corp.intel.com> References: <153176041838.12695.3365448145295112857.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: akpm@linux-foundation.org Cc: jack@suse.cz, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, hch@lst.de List-ID: From: Huaisheng Ye dcssblk_direct_access() needs to check the validity of pointer pfn for NULL assignment. If pfn equals to NULL, it doesn't need to calculate the value. This is in support of asynchronous memmap init and avoid page lookups when possible. Signed-off-by: Huaisheng Ye Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- drivers/s390/block/dcssblk.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index ed607288e696..a645b2c93c34 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -923,8 +923,9 @@ __dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff, 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 (pfn) + *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), + PFN_DEV|PFN_SPECIAL); return (dev_sz - offset) / PAGE_SIZE; } _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm