From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B63D4C369CA for ; Fri, 18 Apr 2025 16:42:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XUb00FgB5IGWrPIO9NOxFIeWzcKnp0zYXplGKwaLpKE=; b=M2GWqsKKchSZj+x6aBxRDxxwwB pNT0p8N5ACNRRZEapaD7NHXsVDsYR6NzK1jFqHubPPpfYHZmkoHfjHyX9/ma5BPh6UV/WGJI5UDkP FI19CJhrTlpq2pnUpNoXCbZJpxzUYWJTQB3G8fQeAzkVGPglnq8wtjxDjQAOO4FMB1m3AuVeV/6Bo Yv8osDzEn1AvnVvV+YuZMKMozv2wW5Mm2bFfPDNcXuJd0A2ZDzgZeVSN1A/yU6b7CuZmB/zSOt3/M k+NQVFm3eS13PeaIUsEIv+Lwht9cOwgBbOdieoNIs0vqEw97VF/upDdGG0KM9VuWfeyn+miYYIp// NR8izLTQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u5ona-0000000Gzwa-1O0g; Fri, 18 Apr 2025 16:42:42 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u5fWa-0000000FJOw-0DLv for linux-nvme@lists.infradead.org; Fri, 18 Apr 2025 06:48:32 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id BAE6168481; Fri, 18 Apr 2025 06:48:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 603A4C4CEE2; Fri, 18 Apr 2025 06:48:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744958911; bh=yOniWqL++YZaDfzZaCSY7YnTRY/fJoU6UIBB3ZlAGj4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LvCJYaeRT0QT6JHX0IAof9Jay3VLFlYiNVXchwWQlDG3b9bpLSac4tbtBXc0Zk88H qp0FtM1F1yBnANGawmZrgkzKr/bYmbidWLdJQtkpUAteaG5zDXBPtg/CxN6ULVp1eH qs7JCn8d25pjuqWWp91BPyfLyM9k57DE0MxBWwlcvCrt7AIhjoFgB6DHYhfEbp0oj8 2UWG1Dc0sN4ZCcrQVfjCuUlEgSHyMLg3UjMw+FxCEVGsf1wIo/Tv626CydZ4SYbbKf P549WLYT8Q6Mn20f9YqwNR02jCCbrj2uepZSXRloxB1s6NUfBV19UaRpkfh2s5qQ7/ Q3EjrOrFMKz7w== From: Leon Romanovsky To: Marek Szyprowski , Jens Axboe , Christoph Hellwig , Keith Busch Cc: Jake Edge , Jonathan Corbet , Jason Gunthorpe , Zhu Yanjun , Robin Murphy , Joerg Roedel , Will Deacon , Sagi Grimberg , Bjorn Helgaas , Logan Gunthorpe , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Andrew Morton , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, Niklas Schnelle , Chuck Lever , Luis Chamberlain , Matthew Wilcox , Dan Williams , Kanchan Joshi , Chaitanya Kulkarni , Leon Romanovsky Subject: [PATCH v8 08/24] dma-mapping: add a dma_need_unmap helper Date: Fri, 18 Apr 2025 09:47:38 +0300 Message-ID: X-Mailer: git-send-email 2.49.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Fri, 18 Apr 2025 09:39:28 -0700 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: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org From: Christoph Hellwig Add helper that allows a driver to skip calling dma_unmap_* if the DMA layer can guarantee that they are no-nops. Signed-off-by: Christoph Hellwig Signed-off-by: Leon Romanovsky --- include/linux/dma-mapping.h | 5 +++++ kernel/dma/mapping.c | 18 ++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index a71e110f1e9d..d2f358c5a25d 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -406,6 +406,7 @@ static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr) { return dma_dev_need_sync(dev) ? __dma_need_sync(dev, dma_addr) : false; } +bool dma_need_unmap(struct device *dev); #else /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */ static inline bool dma_dev_need_sync(const struct device *dev) { @@ -431,6 +432,10 @@ static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr) { return false; } +static inline bool dma_need_unmap(struct device *dev) +{ + return false; +} #endif /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */ struct page *dma_alloc_pages(struct device *dev, size_t size, diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index cda127027e48..3c3204ad2839 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -443,6 +443,24 @@ bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr) } EXPORT_SYMBOL_GPL(__dma_need_sync); +/** + * dma_need_unmap - does this device need dma_unmap_* operations + * @dev: device to check + * + * If this function returns %false, drivers can skip calling dma_unmap_* after + * finishing an I/O. This function must be called after all mappings that might + * need to be unmapped have been performed. + */ +bool dma_need_unmap(struct device *dev) +{ + if (!dma_map_direct(dev, get_dma_ops(dev))) + return true; + if (!dev->dma_skip_sync) + return true; + return IS_ENABLED(CONFIG_DMA_API_DEBUG); +} +EXPORT_SYMBOL_GPL(dma_need_unmap); + static void dma_setup_need_sync(struct device *dev) { const struct dma_map_ops *ops = get_dma_ops(dev); -- 2.49.0