From patchwork Thu Aug 10 16:00:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Weinberger X-Patchwork-Id: 1819937 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.infradead.org (client-ip=2607:7c80:54:3::133; helo=bombadil.infradead.org; envelope-from=linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=ze308bV/; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RMBVn0ScFz1yfW for ; Fri, 11 Aug 2023 02:01:21 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=nKIh2qOW2eCsOQGRm9AJEShdc/wAmhpTH22XSt19MeA=; b=ze308bV/+/cqwe iCMNpAJxgHF2NWOinstcke+avyzp3A8PwvpfhNkFjzfvyVQUdd/eCW4v/5d7isSd7rlkrKOhmQA51 3Sdl5CDdSeeTd7OhPR4Pt8qI0u4SoPy+E+nWm+c5x1RPgC97fTlFZwqh0YQnEd7+mK7TSaW0D0s0o tanJACI2kZPdKCFNT6+pBrk7l4cqJRNkRWEKrPIqrnKwXSjkchVhUPDTMZGAGhl8C8bvZKh0Bswb5 pqec2gp1b32fTKjQnAD4PTjhPo56YYggoga7jckbX2zorBy6cdoHIm8aY36oBtwu8ui4vm0+3VsXN JxdWOYcdk4Ht4TfjipjQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qU85i-0086l8-2G; Thu, 10 Aug 2023 16:00:50 +0000 Received: from lithops.sigma-star.at ([195.201.40.130]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qU85c-0086ep-1F for linux-mtd@lists.infradead.org; Thu, 10 Aug 2023 16:00:47 +0000 Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 88BAB622F562; Thu, 10 Aug 2023 18:00:40 +0200 (CEST) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id EDfStOmQ8fP8; Thu, 10 Aug 2023 18:00:40 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 1C754635D2A1; Thu, 10 Aug 2023 18:00:40 +0200 (CEST) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id yaVTxL2OMKCP; Thu, 10 Aug 2023 18:00:40 +0200 (CEST) Received: from foxxylove.corp.sigma-star.at (unknown [82.150.214.1]) by lithops.sigma-star.at (Postfix) with ESMTPSA id AF6E1635D295; Thu, 10 Aug 2023 18:00:39 +0200 (CEST) From: Richard Weinberger To: linux-mtd@lists.infradead.org Cc: Christoph Hellwig , Stephan Wurm , Richard Weinberger , Miquel Raynal , Vignesh Raghavendra , Oliver Neukum , Ali Akcaagac , Jamie Lenehan , "James E.J. Bottomley" , "Martin K. Petersen" , Ezequiel Garcia , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Subject: [PATCH 2/7] scatterlist: Add kmap helpers Date: Thu, 10 Aug 2023 18:00:13 +0200 Message-Id: <20230810160019.16977-3-richard@nod.at> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20230810160019.16977-1-richard@nod.at> References: <20230810160019.16977-1-richard@nod.at> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230810_090044_747378_5A63D1AA X-CRM114-Status: GOOD ( 14.53 ) X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "bombadil.infradead.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: kmap_sg() is basically scsi_kmap_atomic_sg() but uses kmap_local() and does not enforce disabled interrupts. Signed-off-by: Richard Weinberger --- include/linux/scatterlist.h | 3 ++ lib/scatterlist.c | 55 +++++++++++++++++++++++++++++++++++++ 2 files changed, 58 insertions(+) Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 0.0 T_SPF_PERMERROR SPF: test of record failed (permerror) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org kmap_sg() is basically scsi_kmap_atomic_sg() but uses kmap_local() and does not enforce disabled interrupts. Signed-off-by: Richard Weinberger --- include/linux/scatterlist.h | 3 ++ lib/scatterlist.c | 55 +++++++++++++++++++++++++++++++++++++ 2 files changed, 58 insertions(+) diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 77df3d7b18a61..dd25a87609491 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -692,4 +692,7 @@ bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset); bool sg_miter_next(struct sg_mapping_iter *miter); void sg_miter_stop(struct sg_mapping_iter *miter); +void *kmap_sg(struct scatterlist *sgl, int sg_count, size_t *offset, size_t *len); +void kunmap_sg(void *virt); + #endif /* _LINUX_SCATTERLIST_H */ diff --git a/lib/scatterlist.c b/lib/scatterlist.c index e86231a44c3de..7428d9461711d 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -1364,3 +1364,58 @@ ssize_t extract_iter_to_sg(struct iov_iter *iter, size_t maxsize, } } EXPORT_SYMBOL_GPL(extract_iter_to_sg); + +/** + * kmap_sg - find and kmap an sg-elemnt + * @sgl: scatter-gather list + * @sg_count: number of segments in sg + * @offset: offset in bytes into sg, on return offset into the mapped area + * @len: bytes to map, on return number of bytes mapped + * + * Returns virtual address of the start of the mapped page + */ +void *kmap_sg(struct scatterlist *sgl, int sg_count, size_t *offset, size_t *len) +{ + int i; + size_t sg_len = 0, len_complete = 0; + struct scatterlist *sg; + struct page *page; + + for_each_sg(sgl, sg, sg_count, i) { + len_complete = sg_len; /* Complete sg-entries */ + sg_len += sg->length; + if (sg_len > *offset) + break; + } + + if (WARN_ON_ONCE(i == sg_count)) { + pr_err("%s: Bytes in sg: %zu, requested offset %zu, elements %d\n", + __func__, sg_len, *offset, sg_count); + return NULL; + } + + /* Offset starting from the beginning of first page in this sg-entry */ + *offset = *offset - len_complete + sg->offset; + + /* Assumption: contiguous pages can be accessed as "page + i" */ + page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); + *offset &= ~PAGE_MASK; + + /* Bytes in this sg-entry from *offset to the end of the page */ + sg_len = PAGE_SIZE - *offset; + if (*len > sg_len) + *len = sg_len; + + return kmap_local_page(page); +} +EXPORT_SYMBOL(kmap_sg); + +/** + * kunmap_sg - atomically unmap a virtual address, previously mapped with kmap_sg + * @virt: virtual address to be unmapped + */ +void kunmap_sg(void *virt) +{ + kunmap_local(virt); +} +EXPORT_SYMBOL(kunmap_sg);