From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ilija Hadzic Subject: [PATCH 16/16] drm: hold mutex in critical sections of render-node code Date: Thu, 29 Mar 2012 12:41:38 -0400 Message-ID: <1333039298-2520-17-git-send-email-ihadzic@research.bell-labs.com> References: <1333039298-2520-1-git-send-email-ihadzic@research.bell-labs.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from ihemail2.lucent.com (ihemail2.lucent.com [135.245.0.35]) by gabe.freedesktop.org (Postfix) with ESMTP id 1BB7D9F598 for ; Thu, 29 Mar 2012 09:42:18 -0700 (PDT) Received: from usnavsmail1.ndc.alcatel-lucent.com (usnavsmail1.ndc.alcatel-lucent.com [135.3.39.9]) by ihemail2.lucent.com (8.13.8/IER-o) with ESMTP id q2TGgCDQ000753 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 29 Mar 2012 11:42:12 -0500 (CDT) Received: from umail.lucent.com (umail-ce2.ndc.lucent.com [135.3.40.63]) by usnavsmail1.ndc.alcatel-lucent.com (8.14.3/8.14.3/GMO) with ESMTP id q2TGgBXc024844 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Thu, 29 Mar 2012 11:42:12 -0500 In-Reply-To: <1333039298-2520-1-git-send-email-ihadzic@research.bell-labs.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org Critical sections are parts of the code where we claim or release resources (we don't want two render-node create or remove ioctl called in the context of different processes to claim part of requested resources because of the race). Another critical section is manipulating the render node list. We can use dev->struct_mutex for both. Signed-off-by: Ilija Hadzic --- drivers/gpu/drm/drm_stub.c | 15 ++++++++++++++- 1 files changed, 14 insertions(+), 1 deletions(-) diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c index b025ad8..8abfb08 100644 --- a/drivers/gpu/drm/drm_stub.c +++ b/drivers/gpu/drm/drm_stub.c @@ -480,6 +480,7 @@ static void drm_release_render_node_resources(struct drm_device *dev, int *render_node_owner; int s, e, i, j; + /* no lock, assume we were called with struct_mutex grabbed */ for (e = 0, j = 0; j < DRM_RN_NUM_EXP_TYPES; j++) { s = e; e += resource_count[j]; @@ -503,6 +504,7 @@ static int drm_claim_render_node_resources(struct drm_device *dev, int s, e, i, j; int ret = 0; + mutex_lock(&dev->struct_mutex); for (e = 0, j = 0; j < DRM_RN_NUM_EXP_TYPES; j++) { s = e; e += resource_count[j]; @@ -523,10 +525,12 @@ static int drm_claim_render_node_resources(struct drm_device *dev, *render_node_owner = minor; } } + mutex_unlock(&dev->struct_mutex); return ret; out_release: drm_release_render_node_resources(dev, id_list, resource_count, minor); + mutex_unlock(&dev->struct_mutex); return ret; } @@ -547,7 +551,9 @@ int drm_create_render_node(struct drm_device *dev, struct drm_minor **minor_p) } render_node->minor = minor; *minor_p = minor; + mutex_lock(&dev->struct_mutex); list_add_tail(&render_node->list, &dev->render_node_list); + mutex_unlock(&dev->struct_mutex); return 0; } @@ -555,13 +561,16 @@ int drm_destroy_render_node(struct drm_device *dev, int index) { struct drm_render_node *node, *tmp; + mutex_lock(&dev->struct_mutex); list_for_each_entry_safe(node, tmp, &dev->render_node_list, list) { if (node->minor->index == index) { struct drm_mode_group *group; int resource_count[DRM_RN_NUM_EXP_TYPES]; - if (node->minor->open_count) + if (node->minor->open_count) { + mutex_unlock(&dev->struct_mutex); return -EBUSY; + } group = &node->minor->mode_group; list_del(&node->list); resource_count[0] = group->num_crtcs; @@ -570,12 +579,14 @@ int drm_destroy_render_node(struct drm_device *dev, int index) drm_release_render_node_resources(dev, group->id_list, resource_count, node->minor->index); + mutex_unlock(&dev->struct_mutex); drm_put_minor(&node->minor); drm_mode_group_fini(group); kfree(node); return 0; } } + mutex_unlock(&dev->struct_mutex); return -ENODEV; } @@ -583,6 +594,7 @@ void drm_destroy_all_render_nodes(struct drm_device *dev) { struct drm_render_node *node, *tmp; + mutex_lock(&dev->struct_mutex); list_for_each_entry_safe(node, tmp, &dev->render_node_list, list) { struct drm_mode_group *group; int resource_count[DRM_RN_NUM_EXP_TYPES]; @@ -599,6 +611,7 @@ void drm_destroy_all_render_nodes(struct drm_device *dev) drm_mode_group_fini(group); kfree(node); } + mutex_unlock(&dev->struct_mutex); } /** -- 1.7.8.5