vga_switcheroo: Add missing locking

The following functions iterate over the client list, invoke client
callbacks or invoke handler callbacks without locking anything at all:

- Introduced by c8e9cf7bb240 ("vga_switcheroo: Add a helper function to
  get the client state"):
  vga_switcheroo_get_client_state()

- Introduced by 0d69704ae348 ("gpu/vga_switcheroo: add driver control
  power feature. (v3)"):
  vga_switcheroo_set_dynamic_switch()
  vga_switcheroo_runtime_suspend()
  vga_switcheroo_runtime_resume()
  vga_switcheroo_runtime_resume_hdmi_audio()

Refactor vga_switcheroo_runtime_resume_hdmi_audio() a bit to be able to
release vgasr_mutex immediately after iterating over the client list.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 86c03b5..1acbe20 100644 (file)
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -347,13 +347,18 @@ find_active_client(struct list_head *head)
 int vga_switcheroo_get_client_state(struct pci_dev *pdev)
 {
        struct vga_switcheroo_client *client;
+       enum vga_switcheroo_state ret;
 
+       mutex_lock(&vgasr_mutex);
        client = find_client_from_pci(&vgasr_priv.clients, pdev);
        if (!client)
-               return VGA_SWITCHEROO_NOT_FOUND;
-       if (!vgasr_priv.active)
-               return VGA_SWITCHEROO_INIT;
-       return client->pwr_state;
+               ret = VGA_SWITCHEROO_NOT_FOUND;
+       else if (!vgasr_priv.active)
+               ret = VGA_SWITCHEROO_INIT;
+       else
+               ret = client->pwr_state;
+       mutex_unlock(&vgasr_mutex);
+       return ret;
 }
 EXPORT_SYMBOL(vga_switcheroo_get_client_state);
 
@@ -845,15 +850,16 @@ void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev,
 {
        struct vga_switcheroo_client *client;
 
+       mutex_lock(&vgasr_mutex);
        client = find_client_from_pci(&vgasr_priv.clients, pdev);
-       if (!client)
-               return;
-
-       if (!client->driver_power_control)
+       if (!client || !client->driver_power_control) {
+               mutex_unlock(&vgasr_mutex);
                return;
+       }
 
        client->pwr_state = dynamic;
        set_audio_state(client->id, dynamic);
+       mutex_unlock(&vgasr_mutex);
 }
 EXPORT_SYMBOL(vga_switcheroo_set_dynamic_switch);
 
@@ -866,9 +872,11 @@ static int vga_switcheroo_runtime_suspend(struct device *dev)
        ret = dev->bus->pm->runtime_suspend(dev);
        if (ret)
                return ret;
+       mutex_lock(&vgasr_mutex);
        if (vgasr_priv.handler->switchto)
                vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD);
        vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF);
+       mutex_unlock(&vgasr_mutex);
        return 0;
 }
 
@@ -877,7 +885,9 @@ static int vga_switcheroo_runtime_resume(struct device *dev)
        struct pci_dev *pdev = to_pci_dev(dev);
        int ret;
 
+       mutex_lock(&vgasr_mutex);
        vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON);
+       mutex_unlock(&vgasr_mutex);
        ret = dev->bus->pm->runtime_resume(dev);
        if (ret)
                return ret;
@@ -923,29 +933,33 @@ EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops);
 static int vga_switcheroo_runtime_resume_hdmi_audio(struct device *dev)
 {
        struct pci_dev *pdev = to_pci_dev(dev);
+       struct vga_switcheroo_client *client;
+       struct device *video_dev = NULL;
        int ret;
-       struct vga_switcheroo_client *client, *found = NULL;
 
        /* we need to check if we have to switch back on the video
           device so the audio device can come back */
+       mutex_lock(&vgasr_mutex);
        list_for_each_entry(client, &vgasr_priv.clients, list) {
                if (PCI_SLOT(client->pdev->devfn) == PCI_SLOT(pdev->devfn) &&
                    client_is_vga(client)) {
-                       found = client;
-                       ret = pm_runtime_get_sync(&client->pdev->dev);
-                       if (ret) {
-                               if (ret != 1)
-                                       return ret;
-                       }
+                       video_dev = &client->pdev->dev;
                        break;
                }
        }
+       mutex_unlock(&vgasr_mutex);
+
+       if (video_dev) {
+               ret = pm_runtime_get_sync(video_dev);
+               if (ret && ret != 1)
+                       return ret;
+       }
        ret = dev->bus->pm->runtime_resume(dev);
 
        /* put the reference for the gpu */
-       if (found) {
-               pm_runtime_mark_last_busy(&found->pdev->dev);
-               pm_runtime_put_autosuspend(&found->pdev->dev);
+       if (video_dev) {
+               pm_runtime_mark_last_busy(video_dev);
+               pm_runtime_put_autosuspend(video_dev);
        }
        return ret;
 }