From patchwork Thu Jul 1 20:20:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Michael J. Ruhl" X-Patchwork-Id: 12354859 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E844C11F69 for ; Thu, 1 Jul 2021 20:20:26 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6B2D061413 for ; Thu, 1 Jul 2021 20:20:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B2D061413 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 80EE06EB37; Thu, 1 Jul 2021 20:20:24 +0000 (UTC) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id A4D116E0B8; Thu, 1 Jul 2021 20:20:23 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10032"; a="272469696" X-IronPort-AV: E=Sophos;i="5.83,315,1616482800"; d="scan'208";a="272469696" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2021 13:20:21 -0700 X-IronPort-AV: E=Sophos;i="5.83,315,1616482800"; d="scan'208";a="448041870" Received: from awvttdev-05.aw.intel.com ([10.228.212.156]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2021 13:20:20 -0700 From: "Michael J. Ruhl" To: michael.j.ruhl@intel.com, daniel@ffwll.ch, thomas.hellstrom@linux.intel.com, ckoenig.leichtzumerken@gmail.com, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, matthew.auld@intel.com, maarten.lankhorst@linux.intel.com Subject: [PATCH v1 1/2] drm/i915/gem: Correct the locking and pin pattern for dma-buf Date: Thu, 1 Jul 2021 16:20:13 -0400 Message-Id: <20210701202014.910098-1-michael.j.ruhl@intel.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Thomas Hellström If our exported dma-bufs are imported by another instance of our driver, that instance will typically have the imported dma-bufs locked during dma_buf_map_attachment(). But the exporter also locks the same reservation object in the map_dma_buf() callback, which leads to recursive locking. So taking the lock inside _pin_pages_unlocked() is incorrect. Additionally, the current pinning code path is contrary to the defined way that pinning should occur. Remove the explicit pin/unpin from the map/umap functions and move them to the attach/detach allowing correct locking to occur, and to match the static dma-buf drm_prime pattern. Add a live selftest to exercise both dynamic and non-dynamic exports. v2: - Extend the selftest with a fake dynamic importer. - Provide real pin and unpin callbacks to not abuse the interface. v3: (ruhl) - Remove the dynamic export support and move the pinning into the attach/detach path. v4: (ruhl) - Put pages does not need to assert on the dma-resv Reported-by: Michael J. Ruhl Signed-off-by: Thomas Hellström Signed-off-by: Michael J. Ruhl --- drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 44 +++++-- .../drm/i915/gem/selftests/i915_gem_dmabuf.c | 116 +++++++++++++++++- 2 files changed, 146 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c index 616c3a2f1baf..ccae17d5f441 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c @@ -12,6 +12,8 @@ #include "i915_gem_object.h" #include "i915_scatterlist.h" +I915_SELFTEST_DECLARE(static bool force_different_devices;) + static struct drm_i915_gem_object *dma_buf_to_obj(struct dma_buf *buf) { return to_intel_bo(buf->priv); @@ -25,15 +27,11 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme struct scatterlist *src, *dst; int ret, i; - ret = i915_gem_object_pin_pages_unlocked(obj); - if (ret) - goto err; - /* Copy sg so that we make an independent mapping */ st = kmalloc(sizeof(struct sg_table), GFP_KERNEL); if (st == NULL) { ret = -ENOMEM; - goto err_unpin_pages; + goto err; } ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL); @@ -58,8 +56,6 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme sg_free_table(st); err_free: kfree(st); -err_unpin_pages: - i915_gem_object_unpin_pages(obj); err: return ERR_PTR(ret); } @@ -68,13 +64,9 @@ static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_table *sg, enum dma_data_direction dir) { - struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf); - dma_unmap_sgtable(attachment->dev, sg, dir, DMA_ATTR_SKIP_CPU_SYNC); sg_free_table(sg); kfree(sg); - - i915_gem_object_unpin_pages(obj); } static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct dma_buf_map *map) @@ -168,7 +160,32 @@ static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direct return err; } +/** + * i915_gem_dmabuf_attach - Do any extra attach work necessary + * @dmabuf: imported dma-buf + * @attach: new attach to do work on + * + */ +static int i915_gem_dmabuf_attach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attach) +{ + struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf); + + assert_object_held(obj); + return i915_gem_object_pin_pages(obj); +} + +static void i915_gem_dmabuf_detach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attach) +{ + struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf); + + i915_gem_object_unpin_pages(obj); +} + static const struct dma_buf_ops i915_dmabuf_ops = { + .attach = i915_gem_dmabuf_attach, + .detach = i915_gem_dmabuf_detach, .map_dma_buf = i915_gem_map_dma_buf, .unmap_dma_buf = i915_gem_unmap_dma_buf, .release = drm_gem_dmabuf_release, @@ -204,6 +221,8 @@ static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj) struct sg_table *pages; unsigned int sg_page_sizes; + assert_object_held(obj); + pages = dma_buf_map_attachment(obj->base.import_attach, DMA_BIDIRECTIONAL); if (IS_ERR(pages)) @@ -241,7 +260,8 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev, if (dma_buf->ops == &i915_dmabuf_ops) { obj = dma_buf_to_obj(dma_buf); /* is it from our device? */ - if (obj->base.dev == dev) { + if (obj->base.dev == dev && + !I915_SELFTEST_ONLY(force_different_devices)) { /* * Importing dmabuf exported from out own gem increases * refcount on gem itself instead of f_count of dmabuf. diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c index dd74bc09ec88..868b3469ecbd 100644 --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c @@ -35,7 +35,7 @@ static int igt_dmabuf_export(void *arg) static int igt_dmabuf_import_self(void *arg) { struct drm_i915_private *i915 = arg; - struct drm_i915_gem_object *obj; + struct drm_i915_gem_object *obj, *import_obj; struct drm_gem_object *import; struct dma_buf *dmabuf; int err; @@ -65,14 +65,125 @@ static int igt_dmabuf_import_self(void *arg) err = -EINVAL; goto out_import; } + import_obj = to_intel_bo(import); + + i915_gem_object_lock(import_obj, NULL); + err = ____i915_gem_object_get_pages(import_obj); + i915_gem_object_unlock(import_obj); + if (err) { + pr_err("Same object dma-buf get_pages failed!\n"); + goto out_import; + } err = 0; out_import: - i915_gem_object_put(to_intel_bo(import)); + i915_gem_object_put(import_obj); +out_dmabuf: + dma_buf_put(dmabuf); +out: + i915_gem_object_put(obj); + return err; +} + +static void igt_dmabuf_move_notify(struct dma_buf_attachment *attach) +{ + GEM_WARN_ON(1); +} + +static const struct dma_buf_attach_ops igt_dmabuf_attach_ops = { + .move_notify = igt_dmabuf_move_notify, +}; + +static int igt_dmabuf_import_same_driver(void *arg) +{ + struct drm_i915_private *i915 = arg; + struct drm_i915_gem_object *obj, *import_obj; + struct drm_gem_object *import; + struct dma_buf *dmabuf; + struct dma_buf_attachment *import_attach; + struct sg_table *st; + long timeout; + int err; + + force_different_devices = true; + obj = i915_gem_object_create_shmem(i915, PAGE_SIZE); + if (IS_ERR(obj)) + goto out_ret; + + dmabuf = i915_gem_prime_export(&obj->base, 0); + if (IS_ERR(dmabuf)) { + pr_err("i915_gem_prime_export failed with err=%d\n", + (int)PTR_ERR(dmabuf)); + err = PTR_ERR(dmabuf); + goto out; + } + + import = i915_gem_prime_import(&i915->drm, dmabuf); + if (IS_ERR(import)) { + pr_err("i915_gem_prime_import failed with err=%d\n", + (int)PTR_ERR(import)); + err = PTR_ERR(import); + goto out_dmabuf; + } + + if (import == &obj->base) { + pr_err("i915_gem_prime_import reused gem object!\n"); + err = -EINVAL; + goto out_import; + } + + import_obj = to_intel_bo(import); + + i915_gem_object_lock(import_obj, NULL); + err = ____i915_gem_object_get_pages(import_obj); + if (err) { + pr_err("Different objects dma-buf get_pages failed!\n"); + i915_gem_object_unlock(import_obj); + goto out_import; + } + + /* + * If the exported object is not in system memory, something + * weird is going on. TODO: When p2p is supported, this is no + * longer considered weird. + */ + if (obj->mm.region != i915->mm.regions[INTEL_REGION_SMEM]) { + pr_err("Exported dma-buf is not in system memory\n"); + err = -EINVAL; + } + + i915_gem_object_unlock(import_obj); + + /* Now try a fake dynamic importer */ + import_attach = dma_buf_dynamic_attach(dmabuf, obj->base.dev->dev, + &igt_dmabuf_attach_ops, + NULL); + if (IS_ERR(import_attach)) + goto out_import; + + dma_resv_lock(dmabuf->resv, NULL); + st = dma_buf_map_attachment(import_attach, DMA_BIDIRECTIONAL); + dma_resv_unlock(dmabuf->resv); + if (IS_ERR(st)) + goto out_detach; + + timeout = dma_resv_wait_timeout(dmabuf->resv, false, true, 5 * HZ); + if (!timeout) { + pr_err("dmabuf wait for exclusive fence timed out.\n"); + timeout = -ETIME; + } + err = timeout > 0 ? 0 : timeout; + dma_buf_unmap_attachment(import_attach, st, DMA_BIDIRECTIONAL); +out_detach: + dma_buf_detach(dmabuf, import_attach); +out_import: + i915_gem_object_put(import_obj); out_dmabuf: dma_buf_put(dmabuf); out: i915_gem_object_put(obj); +out_ret: + force_different_devices = false; return err; } @@ -286,6 +397,7 @@ int i915_gem_dmabuf_live_selftests(struct drm_i915_private *i915) { static const struct i915_subtest tests[] = { SUBTEST(igt_dmabuf_export), + SUBTEST(igt_dmabuf_import_same_driver), }; return i915_subtests(tests, i915);