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usb: gadget: f_hid: Use spinlock instead of mutex

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As IN request has to be allocated in set_alt() and released in
disable() we cannot use mutex to protect it as we cannot sleep
in those funcitons. Let's replace this mutex with a spinlock.

Cc: stable@vger.kernel.org
Tested-by: David Lechner <david@lechnology.com>
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Krzysztof Opasiak 2017-01-19 18:55:29 +01:00 committed by Felipe Balbi
parent aa65d11aa0
commit 33e4c1a998
1 changed files with 34 additions and 23 deletions
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57
drivers/usb/gadget/function/f_hid.c
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@ -50,12 +50,12 @@ struct f_hidg {
/* recv report */
struct list_head completed_out_req;
spinlock_t spinlock;
spinlock_t read_spinlock;
wait_queue_head_t read_queue;
unsigned int qlen;
/* send report */
struct mutex lock;
spinlock_t write_spinlock;
bool write_pending;
wait_queue_head_t write_queue;
struct usb_request *req;
@ -258,20 +258,20 @@ static ssize_t f_hidg_read(struct file *file, char __user *buffer,
if (!access_ok(VERIFY_WRITE, buffer, count))
return -EFAULT;
spin_lock_irqsave(&hidg->spinlock, flags);
spin_lock_irqsave(&hidg->read_spinlock, flags);
#define READ_COND (!list_empty(&hidg->completed_out_req))
/* wait for at least one buffer to complete */
while (!READ_COND) {
spin_unlock_irqrestore(&hidg->spinlock, flags);
spin_unlock_irqrestore(&hidg->read_spinlock, flags);
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
if (wait_event_interruptible(hidg->read_queue, READ_COND))
return -ERESTARTSYS;
spin_lock_irqsave(&hidg->spinlock, flags);
spin_lock_irqsave(&hidg->read_spinlock, flags);
}
/* pick the first one */
@ -286,7 +286,7 @@ static ssize_t f_hidg_read(struct file *file, char __user *buffer,
req = list->req;
count = min_t(unsigned int, count, req->actual - list->pos);
spin_unlock_irqrestore(&hidg->spinlock, flags);
spin_unlock_irqrestore(&hidg->read_spinlock, flags);
/* copy to user outside spinlock */
count -= copy_to_user(buffer, req->buf + list->pos, count);
@ -308,9 +308,9 @@ static ssize_t f_hidg_read(struct file *file, char __user *buffer,
return ret;
}
} else {
spin_lock_irqsave(&hidg->spinlock, flags);
spin_lock_irqsave(&hidg->read_spinlock, flags);
list_add(&list->list, &hidg->completed_out_req);
spin_unlock_irqrestore(&hidg->spinlock, flags);
spin_unlock_irqrestore(&hidg->read_spinlock, flags);
wake_up(&hidg->read_queue);
}
@ -321,13 +321,16 @@ static ssize_t f_hidg_read(struct file *file, char __user *buffer,
static void f_hidg_req_complete(struct usb_ep *ep, struct usb_request *req)
{
struct f_hidg *hidg = (struct f_hidg *)ep->driver_data;
unsigned long flags;
if (req->status != 0) {
ERROR(hidg->func.config->cdev,
"End Point Request ERROR: %d\n", req->status);
}
spin_lock_irqsave(&hidg->write_spinlock, flags);
hidg->write_pending = 0;
spin_unlock_irqrestore(&hidg->write_spinlock, flags);
wake_up(&hidg->write_queue);
}
@ -335,18 +338,19 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
size_t count, loff_t *offp)
{
struct f_hidg *hidg = file->private_data;
unsigned long flags;
ssize_t status = -ENOMEM;
if (!access_ok(VERIFY_READ, buffer, count))
return -EFAULT;
mutex_lock(&hidg->lock);
spin_lock_irqsave(&hidg->write_spinlock, flags);
#define WRITE_COND (!hidg->write_pending)
/* write queue */
while (!WRITE_COND) {
mutex_unlock(&hidg->lock);
spin_unlock_irqrestore(&hidg->write_spinlock, flags);
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
@ -354,17 +358,20 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
hidg->write_queue, WRITE_COND))
return -ERESTARTSYS;
mutex_lock(&hidg->lock);
spin_lock_irqsave(&hidg->write_spinlock, flags);
}
hidg->write_pending = 1;
count = min_t(unsigned, count, hidg->report_length);
spin_unlock_irqrestore(&hidg->write_spinlock, flags);
status = copy_from_user(hidg->req->buf, buffer, count);
if (status != 0) {
ERROR(hidg->func.config->cdev,
"copy_from_user error\n");
mutex_unlock(&hidg->lock);
return -EINVAL;
status = -EINVAL;
goto release_write_pending;
}
hidg->req->status = 0;
@ -372,19 +379,23 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
hidg->req->length = count;
hidg->req->complete = f_hidg_req_complete;
hidg->req->context = hidg;
hidg->write_pending = 1;
status = usb_ep_queue(hidg->in_ep, hidg->req, GFP_ATOMIC);
if (status < 0) {
ERROR(hidg->func.config->cdev,
"usb_ep_queue error on int endpoint %zd\n", status);
hidg->write_pending = 0;
wake_up(&hidg->write_queue);
goto release_write_pending;
} else {
status = count;
}
mutex_unlock(&hidg->lock);
return status;
release_write_pending:
spin_lock_irqsave(&hidg->write_spinlock, flags);
hidg->write_pending = 0;
spin_unlock_irqrestore(&hidg->write_spinlock, flags);
wake_up(&hidg->write_queue);
return status;
}
@ -451,9 +462,9 @@ static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req)
req_list->req = req;
spin_lock_irqsave(&hidg->spinlock, flags);
spin_lock_irqsave(&hidg->read_spinlock, flags);
list_add_tail(&req_list->list, &hidg->completed_out_req);
spin_unlock_irqrestore(&hidg->spinlock, flags);
spin_unlock_irqrestore(&hidg->read_spinlock, flags);
wake_up(&hidg->read_queue);
break;
@ -577,13 +588,13 @@ static void hidg_disable(struct usb_function *f)
usb_ep_disable(hidg->in_ep);
usb_ep_disable(hidg->out_ep);
spin_lock_irqsave(&hidg->spinlock, flags);
spin_lock_irqsave(&hidg->read_spinlock, flags);
list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) {
free_ep_req(hidg->out_ep, list->req);
list_del(&list->list);
kfree(list);
}
spin_unlock_irqrestore(&hidg->spinlock, flags);
spin_unlock_irqrestore(&hidg->read_spinlock, flags);
}
static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
@ -743,8 +754,8 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
if (status)
goto fail;
mutex_init(&hidg->lock);
spin_lock_init(&hidg->spinlock);
spin_lock_init(&hidg->write_spinlock);
spin_lock_init(&hidg->read_spinlock);
init_waitqueue_head(&hidg->write_queue);
init_waitqueue_head(&hidg->read_queue);
INIT_LIST_HEAD(&hidg->completed_out_req);