From patchwork Thu Jul 9 20:42:19 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 493563 Return-Path: X-Original-To: incoming-imx@patchwork.ozlabs.org Delivered-To: patchwork-incoming-imx@bilbo.ozlabs.org Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2001:1868:205::9]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id A324B140273 for ; Fri, 10 Jul 2015 06:46:40 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZDIgM-0000pS-Lj; Thu, 09 Jul 2015 20:44:34 +0000 Received: from smtp02.citrix.com ([66.165.176.63]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZDIfx-0000Ys-1Y for linux-arm-kernel@lists.infradead.org; Thu, 09 Jul 2015 20:44:09 +0000 X-IronPort-AV: E=Sophos;i="5.15,442,1432598400"; d="scan'208";a="282741507" From: Julien Grall To: Subject: [PATCH v2 07/20] block/xen-blkfront: split get_grant in 2 Date: Thu, 9 Jul 2015 21:42:19 +0100 Message-ID: <1436474552-31789-8-git-send-email-julien.grall@citrix.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1436474552-31789-1-git-send-email-julien.grall@citrix.com> References: <1436474552-31789-1-git-send-email-julien.grall@citrix.com> MIME-Version: 1.0 X-DLP: MIA2 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150709_134409_278523_50E51653 X-CRM114-Status: GOOD ( 16.55 ) X-Spam-Score: -4.6 (----) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-4.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_MSPIKE_H3 RBL: Good reputation (+3) [66.165.176.63 listed in wl.mailspike.net] -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [66.165.176.63 listed in list.dnswl.org] -0.3 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -0.0 SPF_HELO_PASS SPF: HELO matches SPF record -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.0 RCVD_IN_MSPIKE_WL Mailspike good senders X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ian.campbell@citrix.com, Konrad Rzeszutek Wilk , stefano.stabellini@eu.citrix.com, linux-kernel@vger.kernel.org, Julien Grall , David Vrabel , Boris Ostrovsky , linux-arm-kernel@lists.infradead.org, =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+incoming-imx=patchwork.ozlabs.org@lists.infradead.org List-Id: linux-imx-kernel.lists.patchwork.ozlabs.org Prepare the code to support 64KB page granularity. The first implementation will use a full Linux page per indirect and persistent grant. When non-persistent grant is used, each page of a bio request may be split in multiple grant. Furthermore, the field page of the grant structure is only used to copy data from persistent grant or indirect grant. Avoid to set it for other use case as it will have no meaning given the page will be split in multiple grant. Provide 2 functions, to setup indirect grant, the other for bio page. Signed-off-by: Julien Grall Cc: Konrad Rzeszutek Wilk Cc: Roger Pau Monné Cc: Boris Ostrovsky Cc: David Vrabel --- Changes in v2: - Patch added --- drivers/block/xen-blkfront.c | 85 ++++++++++++++++++++++++++++++-------------- 1 file changed, 59 insertions(+), 26 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 7b81d23..95fd067 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -242,34 +242,77 @@ out_of_memory: return -ENOMEM; } -static struct grant *get_grant(grant_ref_t *gref_head, - struct page *page, - struct blkfront_info *info) +static struct grant *get_free_grant(struct blkfront_info *info) { struct grant *gnt_list_entry; - unsigned long buffer_mfn; BUG_ON(list_empty(&info->grants)); gnt_list_entry = list_first_entry(&info->grants, struct grant, - node); + node); list_del(&gnt_list_entry->node); - if (gnt_list_entry->gref != GRANT_INVALID_REF) { + if (gnt_list_entry->gref != GRANT_INVALID_REF) info->persistent_gnts_c--; + + return gnt_list_entry; +} + +static void grant_foreign_access(const struct grant *gnt_list_entry, + const struct blkfront_info *info) +{ + gnttab_page_grant_foreign_access_ref(gnt_list_entry->gref, + info->xbdev->otherend_id, + gnt_list_entry->page, + 0); +} + +static struct grant *get_grant(grant_ref_t *gref_head, + unsigned long mfn, + struct blkfront_info *info) +{ + struct grant *gnt_list_entry = get_free_grant(info); + + if (gnt_list_entry->gref != GRANT_INVALID_REF) return gnt_list_entry; + + /* Assign a gref to this page */ + gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); + BUG_ON(gnt_list_entry->gref == -ENOSPC); + if (info->feature_persistent) + grant_foreign_access(gnt_list_entry, info); + else { + /* Grant access to the MFN passed by the caller */ + gnttab_grant_foreign_access_ref(gnt_list_entry->gref, + info->xbdev->otherend_id, + mfn, 0); } + return gnt_list_entry; +} + +static struct grant *get_indirect_grant(grant_ref_t *gref_head, + struct blkfront_info *info) +{ + struct grant *gnt_list_entry = get_free_grant(info); + + if (gnt_list_entry->gref != GRANT_INVALID_REF) + return gnt_list_entry; + /* Assign a gref to this page */ gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); BUG_ON(gnt_list_entry->gref == -ENOSPC); if (!info->feature_persistent) { - BUG_ON(!page); - gnt_list_entry->page = page; + struct page *indirect_page; + + /* Fetch a pre-allocated page to use for indirect grefs */ + BUG_ON(list_empty(&info->indirect_pages)); + indirect_page = list_first_entry(&info->indirect_pages, + struct page, lru); + list_del(&indirect_page->lru); + gnt_list_entry->page = indirect_page; } - buffer_mfn = page_to_mfn(gnt_list_entry->page); - gnttab_grant_foreign_access_ref(gnt_list_entry->gref, - info->xbdev->otherend_id, - buffer_mfn, 0); + grant_foreign_access(gnt_list_entry, info); + return gnt_list_entry; } @@ -522,29 +565,19 @@ static int blkif_queue_rw_req(struct request *req) if ((ring_req->operation == BLKIF_OP_INDIRECT) && (i % SEGS_PER_INDIRECT_FRAME == 0)) { - struct page *uninitialized_var(page); - if (segments) kunmap_atomic(segments); n = i / SEGS_PER_INDIRECT_FRAME; - if (!info->feature_persistent) { - struct page *indirect_page; - - /* Fetch a pre-allocated page to use for indirect grefs */ - BUG_ON(list_empty(&info->indirect_pages)); - indirect_page = list_first_entry(&info->indirect_pages, - struct page, lru); - list_del(&indirect_page->lru); - page = indirect_page; - } - gnt_list_entry = get_grant(&gref_head, page, info); + gnt_list_entry = get_indirect_grant(&gref_head, info); info->shadow[id].indirect_grants[n] = gnt_list_entry; segments = kmap_atomic(gnt_list_entry->page); ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; } - gnt_list_entry = get_grant(&gref_head, sg_page(sg), info); + gnt_list_entry = get_grant(&gref_head, + page_to_mfn(sg_page(sg)), + info); ref = gnt_list_entry->gref; info->shadow[id].grants_used[i] = gnt_list_entry;