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drm/udl: Replace semaphore with a simple wait queue

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UDL driver uses a semaphore for controlling the emptiness of FIFO in a
slightly funky way.  This patch replaces it with a wait queue and
controls the emptiness with the standard wait_event*() macro instead,
which is a more straightforward implementation.

While we are at it, drop the dead code for delayed semaphore down,
too.

Tested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220804075826.27036-2-tiwai@suse.de
This commit is contained in:
Takashi Iwai
2022-08-04 09:58:23 +02:00
committed by Thomas Zimmermann
parent 504a51d70f
commit acd45c5679
2 changed files with 31 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/gpu/drm/udl/udl_drv.h
+8 -3
View File
@@ -34,14 +34,13 @@ struct udl_device;
struct urb_node {
struct list_head entry;
struct udl_device *dev;
struct delayed_work release_urb_work;
struct urb *urb;
};
struct urb_list {
struct list_head list;
spinlock_t lock;
struct semaphore limit_sem;
wait_queue_head_t sleep;
int available;
int count;
size_t size;
@@ -75,7 +74,13 @@ static inline struct usb_device *udl_to_usb_device(struct udl_device *udl)
int udl_modeset_init(struct drm_device *dev);
struct drm_connector *udl_connector_init(struct drm_device *dev);
struct urb *udl_get_urb(struct drm_device *dev);
struct urb *udl_get_urb_timeout(struct drm_device *dev, long timeout);
#define GET_URB_TIMEOUT HZ
static inline struct urb *udl_get_urb(struct drm_device *dev)
{
return udl_get_urb_timeout(dev, GET_URB_TIMEOUT);
}
int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len);
void udl_urb_completion(struct urb *urb);
drivers/gpu/drm/udl/udl_main.c
+23 -61
View File
@@ -23,9 +23,6 @@
#define WRITES_IN_FLIGHT (4)
#define MAX_VENDOR_DESCRIPTOR_SIZE 256
#define GET_URB_TIMEOUT HZ
#define FREE_URB_TIMEOUT (HZ*2)
static int udl_parse_vendor_descriptor(struct udl_device *udl)
{
struct usb_device *udev = udl_to_usb_device(udl);
@@ -119,14 +116,6 @@ static int udl_select_std_channel(struct udl_device *udl)
return ret < 0 ? ret : 0;
}
static void udl_release_urb_work(struct work_struct *work)
{
struct urb_node *unode = container_of(work, struct urb_node,
release_urb_work.work);
up(&unode->dev->urbs.limit_sem);
}
void udl_urb_completion(struct urb *urb)
{
struct urb_node *unode = urb->context;
@@ -150,23 +139,13 @@ void udl_urb_completion(struct urb *urb)
udl->urbs.available++;
spin_unlock_irqrestore(&udl->urbs.lock, flags);
#if 0
/*
* When using fb_defio, we deadlock if up() is called
* while another is waiting. So queue to another process.
*/
if (fb_defio)
schedule_delayed_work(&unode->release_urb_work, 0);
else
#endif
up(&udl->urbs.limit_sem);
wake_up(&udl->urbs.sleep);
}
static void udl_free_urb_list(struct drm_device *dev)
{
struct udl_device *udl = to_udl(dev);
int count = udl->urbs.count;
struct list_head *node;
struct urb_node *unode;
struct urb *urb;
@@ -174,23 +153,15 @@ static void udl_free_urb_list(struct drm_device *dev)
/* keep waiting and freeing, until we've got 'em all */
while (count--) {
down(&udl->urbs.limit_sem);
spin_lock_irq(&udl->urbs.lock);
node = udl->urbs.list.next; /* have reserved one with sem */
list_del_init(node);
spin_unlock_irq(&udl->urbs.lock);
unode = list_entry(node, struct urb_node, entry);
urb = unode->urb;
urb = udl_get_urb_timeout(dev, MAX_SCHEDULE_TIMEOUT);
if (WARN_ON(!urb))
break;
unode = urb->context;
/* Free each separately allocated piece */
usb_free_coherent(urb->dev, udl->urbs.size,
urb->transfer_buffer, urb->transfer_dma);
usb_free_urb(urb);
kfree(node);
kfree(unode);
}
udl->urbs.count = 0;
}
@@ -210,7 +181,7 @@ retry:
udl->urbs.size = size;
INIT_LIST_HEAD(&udl->urbs.list);
sema_init(&udl->urbs.limit_sem, 0);
init_waitqueue_head(&udl->urbs.sleep);
udl->urbs.count = 0;
udl->urbs.available = 0;
@@ -220,9 +191,6 @@ retry:
break;
unode->dev = udl;
INIT_DELAYED_WORK(&unode->release_urb_work,
udl_release_urb_work);
urb = usb_alloc_urb(0, GFP_KERNEL);
if (!urb) {
kfree(unode);
@@ -250,7 +218,6 @@ retry:
list_add_tail(&unode->entry, &udl->urbs.list);
up(&udl->urbs.limit_sem);
udl->urbs.count++;
udl->urbs.available++;
}
@@ -260,36 +227,31 @@ retry:
return udl->urbs.count;
}
struct urb *udl_get_urb(struct drm_device *dev)
struct urb *udl_get_urb_timeout(struct drm_device *dev, long timeout)
{
struct udl_device *udl = to_udl(dev);
int ret = 0;
struct list_head *entry;
struct urb_node *unode;
struct urb *urb = NULL;
struct urb_node *unode = NULL;
if (!udl->urbs.count)
return NULL;
/* Wait for an in-flight buffer to complete and get re-queued */
ret = down_timeout(&udl->urbs.limit_sem, GET_URB_TIMEOUT);
if (ret) {
DRM_INFO("wait for urb interrupted: %x available: %d\n",
ret, udl->urbs.available);
goto error;
spin_lock_irq(&udl->urbs.lock);
if (!wait_event_lock_irq_timeout(udl->urbs.sleep,
!list_empty(&udl->urbs.list),
udl->urbs.lock, timeout)) {
DRM_INFO("wait for urb interrupted: available: %d\n",
udl->urbs.available);
goto unlock;
}
spin_lock_irq(&udl->urbs.lock);
BUG_ON(list_empty(&udl->urbs.list)); /* reserved one with limit_sem */
entry = udl->urbs.list.next;
list_del_init(entry);
unode = list_first_entry(&udl->urbs.list, struct urb_node, entry);
list_del_init(&unode->entry);
udl->urbs.available--;
unlock:
spin_unlock_irq(&udl->urbs.lock);
unode = list_entry(entry, struct urb_node, entry);
urb = unode->urb;
error:
return urb;
return unode ? unode->urb : NULL;
}
int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len)