From patchwork Wed Apr 15 10:11:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tvrtko Ursulin X-Patchwork-Id: 11490865 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 54F79112C for ; Wed, 15 Apr 2020 10:11:54 +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 3D49520775 for ; Wed, 15 Apr 2020 10:11:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3D49520775 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com 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 B27A86E94A; Wed, 15 Apr 2020 10:11:53 +0000 (UTC) X-Original-To: Intel-gfx@lists.freedesktop.org Delivered-To: Intel-gfx@lists.freedesktop.org Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id 886F26E947 for ; Wed, 15 Apr 2020 10:11:50 +0000 (UTC) IronPort-SDR: 8x5TsRd585+9S9CH1qHH7n3AgwO8OGjinh7uj22e2Cvr4dIdX8Hi8dsoqIGrtywL3aPiZTsbIu 062Jqq4SB1RA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2020 03:11:50 -0700 IronPort-SDR: KC57slAGLTeOWzqw++6tlAtmP3qt9dy+7UnSu+u3sHR7mcQAgz+F2OW1PnXQuzHkuguGyj4Vev Uqw9jObO7u6Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,386,1580803200"; d="scan'208";a="427385458" Received: from idodadon-mobl1.ger.corp.intel.com (HELO localhost.localdomain) ([10.214.240.154]) by orsmga005.jf.intel.com with ESMTP; 15 Apr 2020 03:11:48 -0700 From: Tvrtko Ursulin To: Intel-gfx@lists.freedesktop.org Date: Wed, 15 Apr 2020 11:11:31 +0100 Message-Id: <20200415101138.26126-3-tvrtko.ursulin@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200415101138.26126-1-tvrtko.ursulin@linux.intel.com> References: <20200415101138.26126-1-tvrtko.ursulin@linux.intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 2/9] drm/i915: Update client name on context create 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: , Cc: Chris Wilson Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" From: Tvrtko Ursulin Some clients have the DRM fd passed to them over a socket by the X server. Grab the real client and pid when they create their first context and update the exposed data for more useful enumeration. To enable lockless access to client name and pid data from the following patches, we also make these fields rcu protected. In this way asynchronous code paths where both contexts which remain after the client exit, and access to client name and pid as they are getting updated due context creation running in parallel with name/pid queries. v2: * Do not leak the pid reference and borrow context idr_lock. (Chris) v3: * More avoiding leaks. (Chris) v4: * Move update completely to drm client. (Chris) * Do not lose previous client data on failure to re-register and simplify update to only touch what it needs. v5: * Reuse ext_data local. (Chris) Signed-off-by: Tvrtko Ursulin Reviewed-by: Chris Wilson --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 5 + drivers/gpu/drm/i915/i915_drm_client.c | 103 ++++++++++++++++++-- drivers/gpu/drm/i915/i915_drm_client.h | 10 +- 3 files changed, 106 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 11d9135cf21a..0a1d1db98d64 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -74,6 +74,7 @@ #include "gt/intel_engine_user.h" #include "gt/intel_ring.h" +#include "i915_drm_client.h" #include "i915_gem_context.h" #include "i915_globals.h" #include "i915_trace.h" @@ -2356,6 +2357,10 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data, return -EIO; } + ret = i915_drm_client_update(ext_data.fpriv->client, current); + if (ret) + return ret; + ext_data.ctx = i915_gem_create_context(i915, args->flags); if (IS_ERR(ext_data.ctx)) return PTR_ERR(ext_data.ctx); diff --git a/drivers/gpu/drm/i915/i915_drm_client.c b/drivers/gpu/drm/i915/i915_drm_client.c index 2067fbcdb795..342a11554573 100644 --- a/drivers/gpu/drm/i915/i915_drm_client.c +++ b/drivers/gpu/drm/i915/i915_drm_client.c @@ -7,6 +7,9 @@ #include #include +#include + +#include "i915_drv.h" #include "i915_drm_client.h" #include "i915_gem.h" #include "i915_utils.h" @@ -22,10 +25,15 @@ show_client_name(struct device *kdev, struct device_attribute *attr, char *buf) { struct i915_drm_client *client = container_of(attr, typeof(*client), attr.name); + int ret; + + rcu_read_lock(); + ret = snprintf(buf, PAGE_SIZE, + READ_ONCE(client->closed) ? "<%s>" : "%s", + rcu_dereference(client->name)); + rcu_read_unlock(); - return snprintf(buf, PAGE_SIZE, - READ_ONCE(client->closed) ? "<%s>" : "%s", - client->name); + return ret; } static ssize_t @@ -33,10 +41,15 @@ show_client_pid(struct device *kdev, struct device_attribute *attr, char *buf) { struct i915_drm_client *client = container_of(attr, typeof(*client), attr.pid); + int ret; - return snprintf(buf, PAGE_SIZE, - READ_ONCE(client->closed) ? "<%u>" : "%u", - pid_nr(client->pid)); + rcu_read_lock(); + ret = snprintf(buf, PAGE_SIZE, + READ_ONCE(client->closed) ? "<%u>" : "%u", + pid_nr(rcu_dereference(client->pid))); + rcu_read_unlock(); + + return ret; } static int @@ -101,8 +114,8 @@ __i915_drm_client_register(struct i915_drm_client *client, if (!name) return -ENOMEM; - client->pid = get_task_pid(task, PIDTYPE_PID); - client->name = name; + rcu_assign_pointer(client->pid, get_task_pid(task, PIDTYPE_PID)); + rcu_assign_pointer(client->name, name); if (!clients->root) return 0; /* intel_fbdev_init registers a client before sysfs */ @@ -125,8 +138,8 @@ __i915_drm_client_unregister(struct i915_drm_client *client) { __client_unregister_sysfs(client); - put_pid(fetch_and_zero(&client->pid)); - kfree(fetch_and_zero(&client->name)); + put_pid(rcu_replace_pointer(client->pid, NULL, true)); + kfree(rcu_replace_pointer(client->name, NULL, true)); } struct i915_drm_client * @@ -140,6 +153,7 @@ i915_drm_client_add(struct i915_drm_clients *clients, struct task_struct *task) return ERR_PTR(-ENOMEM); kref_init(&client->kref); + mutex_init(&client->update_lock); client->clients = clients; ret = xa_alloc_cyclic(&clients->xarray, &client->id, client, @@ -177,3 +191,72 @@ void i915_drm_client_close(struct i915_drm_client *client) WRITE_ONCE(client->closed, true); i915_drm_client_put(client); } + +struct client_update_free { + struct rcu_head rcu; + struct pid *pid; + char *name; +}; + +static void __client_update_free(struct rcu_head *rcu) +{ + struct client_update_free *old = container_of(rcu, typeof(*old), rcu); + + put_pid(old->pid); + kfree(old->name); + kfree(old); +} + +int +i915_drm_client_update(struct i915_drm_client *client, + struct task_struct *task) +{ + struct drm_i915_private *i915 = + container_of(client->clients, typeof(*i915), clients); + struct client_update_free *old; + struct pid *pid; + char *name; + int ret; + + old = kmalloc(sizeof(*old), GFP_KERNEL); + if (!old) + return -ENOMEM; + + ret = mutex_lock_interruptible(&client->update_lock); + if (ret) + goto out_free; + + pid = get_task_pid(task, PIDTYPE_PID); + if (!pid) + goto out_pid; + if (pid == client->pid) + goto out_name; + + name = kstrdup(task->comm, GFP_KERNEL); + if (!name) { + drm_notice(&i915->drm, + "Failed to update client id=%u,name=%s,pid=%u! (%d)\n", + client->id, client->name, pid_nr(client->pid), ret); + goto out_name; + } + + init_rcu_head(&old->rcu); + + old->pid = rcu_replace_pointer(client->pid, pid, true); + old->name = rcu_replace_pointer(client->name, name, true); + + mutex_unlock(&client->update_lock); + + call_rcu(&old->rcu, __client_update_free); + + return 0; + +out_name: + put_pid(pid); +out_pid: + mutex_unlock(&client->update_lock); +out_free: + kfree(old); + + return ret; +} diff --git a/drivers/gpu/drm/i915/i915_drm_client.h b/drivers/gpu/drm/i915/i915_drm_client.h index af6998c74d4c..11b48383881d 100644 --- a/drivers/gpu/drm/i915/i915_drm_client.h +++ b/drivers/gpu/drm/i915/i915_drm_client.h @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -26,9 +27,11 @@ struct i915_drm_client { struct rcu_head rcu; + struct mutex update_lock; /* Serializes name and pid updates. */ + unsigned int id; - struct pid *pid; - char *name; + struct pid __rcu *pid; + char __rcu *name; bool closed; struct i915_drm_clients *clients; @@ -61,4 +64,7 @@ void i915_drm_client_close(struct i915_drm_client *client); struct i915_drm_client *i915_drm_client_add(struct i915_drm_clients *clients, struct task_struct *task); +int i915_drm_client_update(struct i915_drm_client *client, + struct task_struct *task); + #endif /* !__I915_DRM_CLIENT_H__ */