From patchwork Thu Jun 29 21:05:32 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 9817931 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 90E21603D7 for ; Thu, 29 Jun 2017 21:06:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 828C72522B for ; Thu, 29 Jun 2017 21:06:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 76D6A2841E; Thu, 29 Jun 2017 21:06:04 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id E6A502522B for ; Thu, 29 Jun 2017 21:06:03 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2BE426E708; Thu, 29 Jun 2017 21:06:03 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id BFD096E708; Thu, 29 Jun 2017 21:06:01 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 7526495-1500050 for multiple; Thu, 29 Jun 2017 22:05:34 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Thu, 29 Jun 2017 22:05:33 +0100 From: Chris Wilson To: dri-devel@lists.freedesktop.org Subject: [PATCH v2] dma-buf/sw-sync: Fix locking around sync_timeline lists Date: Thu, 29 Jun 2017 22:05:32 +0100 Message-Id: <20170629210532.5617-1-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.13.2 In-Reply-To: <20170629125930.821-6-chris@chris-wilson.co.uk> References: <20170629125930.821-6-chris@chris-wilson.co.uk> X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Cc: intel-gfx@lists.freedesktop.org X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP The sync_pt were not adding themselves atomically to the timeline lists, corruption imminent. Only a single list is required to track the unsignaled sync_pt, so reduce it and rename the lock more appropriately along with using idiomatic names to distinguish a list from links along it. v2: Prevent spinlock recursion on free during create (next patch) and fixup crossref in kerneldoc Signed-off-by: Chris Wilson Cc: Sumit Semwal Cc: Sean Paul Cc: Gustavo Padovan --- drivers/dma-buf/sw_sync.c | 48 ++++++++++++++++++-------------------------- drivers/dma-buf/sync_debug.c | 9 ++++----- drivers/dma-buf/sync_debug.h | 21 ++++++++----------- 3 files changed, 31 insertions(+), 47 deletions(-) diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c index 6effa1ce010e..f20d18c421a3 100644 --- a/drivers/dma-buf/sw_sync.c +++ b/drivers/dma-buf/sw_sync.c @@ -96,9 +96,8 @@ static struct sync_timeline *sync_timeline_create(const char *name) obj->context = dma_fence_context_alloc(1); strlcpy(obj->name, name, sizeof(obj->name)); - INIT_LIST_HEAD(&obj->child_list_head); - INIT_LIST_HEAD(&obj->active_list_head); - spin_lock_init(&obj->child_list_lock); + INIT_LIST_HEAD(&obj->pt_list); + spin_lock_init(&obj->lock); sync_timeline_debug_add(obj); @@ -139,17 +138,15 @@ static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc) trace_sync_timeline(obj); - spin_lock_irq(&obj->child_list_lock); + spin_lock_irq(&obj->lock); obj->value += inc; - list_for_each_entry_safe(pt, next, &obj->active_list_head, - active_list) { + list_for_each_entry_safe(pt, next, &obj->pt_list, link) if (dma_fence_is_signaled_locked(&pt->base)) - list_del_init(&pt->active_list); - } + list_del_init(&pt->link); - spin_unlock_irq(&obj->child_list_lock); + spin_unlock_irq(&obj->lock); } /** @@ -171,15 +168,15 @@ static struct sync_pt *sync_pt_create(struct sync_timeline *obj, if (!pt) return NULL; - spin_lock_irq(&obj->child_list_lock); - sync_timeline_get(obj); - dma_fence_init(&pt->base, &timeline_fence_ops, &obj->child_list_lock, + dma_fence_init(&pt->base, &timeline_fence_ops, &obj->lock, obj->context, value); - list_add_tail(&pt->child_list, &obj->child_list_head); - INIT_LIST_HEAD(&pt->active_list); + INIT_LIST_HEAD(&pt->link); - spin_unlock_irq(&obj->child_list_lock); + spin_lock_irq(&obj->lock); + if (!dma_fence_is_signaled_locked(&pt->base)) + list_add_tail(&pt->link, &obj->pt_list); + spin_unlock_irq(&obj->lock); return pt; } @@ -200,15 +197,15 @@ static void timeline_fence_release(struct dma_fence *fence) { struct sync_pt *pt = dma_fence_to_sync_pt(fence); struct sync_timeline *parent = dma_fence_parent(fence); - unsigned long flags; - spin_lock_irqsave(fence->lock, flags); + if (!list_empty(&pt->link)) { + unsigned long flags; - list_del(&pt->child_list); - if (!list_empty(&pt->active_list)) - list_del(&pt->active_list); - - spin_unlock_irqrestore(fence->lock, flags); + spin_lock_irqsave(fence->lock, flags); + if (!list_empty(&pt->link)) + list_del(&pt->link); + spin_unlock_irqrestore(fence->lock, flags); + } sync_timeline_put(parent); dma_fence_free(fence); @@ -223,13 +220,6 @@ static bool timeline_fence_signaled(struct dma_fence *fence) static bool timeline_fence_enable_signaling(struct dma_fence *fence) { - struct sync_pt *pt = dma_fence_to_sync_pt(fence); - struct sync_timeline *parent = dma_fence_parent(fence); - - if (timeline_fence_signaled(fence)) - return false; - - list_add_tail(&pt->active_list, &parent->active_list_head); return true; } diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c index 0e91632248ba..2264a075f6a9 100644 --- a/drivers/dma-buf/sync_debug.c +++ b/drivers/dma-buf/sync_debug.c @@ -119,13 +119,12 @@ static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj) seq_printf(s, "%s: %d\n", obj->name, obj->value); - spin_lock_irq(&obj->child_list_lock); - list_for_each(pos, &obj->child_list_head) { - struct sync_pt *pt = - container_of(pos, struct sync_pt, child_list); + spin_lock_irq(&obj->lock); + list_for_each(pos, &obj->pt_list) { + struct sync_pt *pt = container_of(pos, struct sync_pt, link); sync_print_fence(s, &pt->base, false); } - spin_unlock_irq(&obj->child_list_lock); + spin_unlock_irq(&obj->lock); } static void sync_print_sync_file(struct seq_file *s, diff --git a/drivers/dma-buf/sync_debug.h b/drivers/dma-buf/sync_debug.h index 26fe8b9907b3..6a2a8e69a7d0 100644 --- a/drivers/dma-buf/sync_debug.h +++ b/drivers/dma-buf/sync_debug.h @@ -24,42 +24,37 @@ * struct sync_timeline - sync object * @kref: reference count on fence. * @name: name of the sync_timeline. Useful for debugging - * @child_list_head: list of children sync_pts for this sync_timeline - * @child_list_lock: lock protecting @child_list_head and fence.status - * @active_list_head: list of active (unsignaled/errored) sync_pts + * @lock: lock protecting @pt_list and @value + * @pt_list: list of active (unsignaled/errored) sync_pts * @sync_timeline_list: membership in global sync_timeline_list */ struct sync_timeline { struct kref kref; char name[32]; - /* protected by child_list_lock */ + /* protected by lock */ u64 context; int value; - struct list_head child_list_head; - spinlock_t child_list_lock; - - struct list_head active_list_head; + struct list_head pt_list; + spinlock_t lock; struct list_head sync_timeline_list; }; static inline struct sync_timeline *dma_fence_parent(struct dma_fence *fence) { - return container_of(fence->lock, struct sync_timeline, child_list_lock); + return container_of(fence->lock, struct sync_timeline, lock); } /** * struct sync_pt - sync_pt object * @base: base fence object - * @child_list: sync timeline child's list - * @active_list: sync timeline active child's list + * @link: link on the sync timeline's list */ struct sync_pt { struct dma_fence base; - struct list_head child_list; - struct list_head active_list; + struct list_head link; }; #ifdef CONFIG_SW_SYNC