From patchwork Wed Jan 1 12:17:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11315085 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2FC13139A for ; Wed, 1 Jan 2020 12:17:29 +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 1162F206E6 for ; Wed, 1 Jan 2020 12:17:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1162F206E6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8A29A89686; Wed, 1 Jan 2020 12:17:26 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id A41FC89686 for ; Wed, 1 Jan 2020 12:17:25 +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 19741476-1500050 for multiple; Wed, 01 Jan 2020 12:17:19 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Wed, 1 Jan 2020 12:17:17 +0000 Message-Id: <20200101121717.662220-2-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.25.0.rc0 In-Reply-To: <20200101121717.662220-1-chris@chris-wilson.co.uk> References: <20200101121717.662220-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 2/2] drm/i915/gem: Drop local vma->vm_file reference X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" We use the global device inode, shared amongst all files, and not the user's device filp to provide the backing storage for the mmap. The vma->vm_file provides a redundant reference that breaks existing expected behaviour that closing the user's device fd will release the resources bound to it, if a mmap persists. (Even without the vma->vm_file, the mmap will persist past the user's fd as the storage is bound to the device, i.e. our reference is on the object not file.) Fixes: cc662126b413 ("drm/i915: Introduce DRM_I915_GEM_MMAP_OFFSET") Closes: https://gitlab.freedesktop.org/drm/intel/issues/919 Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/gem/i915_gem_mman.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c index 905527ce2999..6486ecf5642c 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c @@ -699,6 +699,7 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma) struct drm_device *dev = priv->minor->dev; struct i915_mmap_offset *mmo = NULL; struct drm_gem_object *obj = NULL; + struct file *anon; if (drm_dev_is_unplugged(dev)) return -ENODEV; @@ -747,9 +748,22 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma) vma->vm_flags &= ~VM_MAYWRITE; } + anon = drm_file_create_anon(dev->primary, vma->vm_file->f_flags); + if (IS_ERR(anon)) { + drm_gem_object_put_unlocked(obj); + return PTR_ERR(anon); + } + vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; vma->vm_private_data = mmo; + /* + * We keep the ref on mmo->obj, not vm_file, but we require + * vma->vm_file->f_mapping, see vma_link(), for later revocation. + */ + fput(vma->vm_file); + vma->vm_file = anon; + switch (mmo->mmap_type) { case I915_MMAP_TYPE_WC: vma->vm_page_prot =