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Sat, 13 Mar 2021 01:39:14 +0000 Received: from mga03.intel.com ([134.134.136.65]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lKtFD-00Cfyy-QN for linux-nvme@lists.infradead.org; Sat, 13 Mar 2021 01:39:12 +0000 IronPort-SDR: KvRSNyq0OpyaGF8LVlSzDeb41FqkbJVDqaQaQVxh5n4ukS7obPr2E+uQPAXf2ma+AmRaWPeG8E 7S35UjTlkO2Q== X-IronPort-AV: E=McAfee;i="6000,8403,9921"; a="188954915" X-IronPort-AV: E=Sophos;i="5.81,245,1610438400"; d="scan'208";a="188954915" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Mar 2021 17:38:57 -0800 IronPort-SDR: WX0p9R69J0SqVVtAjuI1NyCDa3GoAa0N7h3vw3KXR0KEY1AUvz5NjcbA4fhWSGyck6WC+6RtZ6 ly3N0e+cpIbQ== X-IronPort-AV: E=Sophos;i="5.81,245,1610438400"; d="scan'208";a="404606308" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Mar 2021 17:38:56 -0800 Date: Fri, 12 Mar 2021 17:38:56 -0800 From: Ira Weiny To: Logan Gunthorpe Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , Christian =?iso-8859-1?Q?K=F6nig?= , Ira Weiny , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin Subject: Re: [RFC PATCH v2 04/11] PCI/P2PDMA: Introduce pci_p2pdma_should_map_bus() and pci_p2pdma_bus_offset() Message-ID: <20210313013856.GA3402637@iweiny-DESK2.sc.intel.com> References: <20210311233142.7900-1-logang@deltatee.com> <20210311233142.7900-5-logang@deltatee.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210311233142.7900-5-logang@deltatee.com> User-Agent: Mutt/1.11.1 (2018-12-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210313_013910_616960_7B1D6D89 X-CRM114-Status: GOOD ( 16.09 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, Mar 11, 2021 at 04:31:34PM -0700, Logan Gunthorpe wrote: > Introduce pci_p2pdma_should_map_bus() which is meant to be called by > DMA map functions to determine how to map a given p2pdma page. > > pci_p2pdma_bus_offset() is also added to allow callers to get the bus > offset if they need to map the bus address. > > Signed-off-by: Logan Gunthorpe > --- > drivers/pci/p2pdma.c | 50 ++++++++++++++++++++++++++++++++++++++ > include/linux/pci-p2pdma.h | 11 +++++++++ > 2 files changed, 61 insertions(+) > > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > index 7f6836732bce..66d16b7eb668 100644 > --- a/drivers/pci/p2pdma.c > +++ b/drivers/pci/p2pdma.c > @@ -912,6 +912,56 @@ void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg, > } > EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs); > > +/** > + * pci_p2pdma_bus_offset - returns the bus offset for a given page > + * @page: page to get the offset for > + * > + * Must be passed a PCI p2pdma page. > + */ > +u64 pci_p2pdma_bus_offset(struct page *page) > +{ > + struct pci_p2pdma_pagemap *p2p_pgmap = to_p2p_pgmap(page->pgmap); > + > + WARN_ON(!is_pci_p2pdma_page(page)); Shouldn't this check be before the to_p2p_pgmap() call? And I've been told not to introduce WARN_ON's. Should this be? if (!is_pci_p2pdma_page(page)) return -1; ??? Ira _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme