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[media] radio-cadet: avoid interruptible_sleep_on race

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interruptible_sleep_on is racy and going away. This replaces
one use in the radio-cadet driver with a wait_event_interruptible
call. Special care was taken that accesses to the rdsin and rdsout
indices are always done with dev->lock held.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Hans Verkuil 2014-02-10 07:21:36 -03:00 committed by Mauro Carvalho Chehab
parent 2dfb1c939c
commit ce0ede2c06
1 changed files with 27 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
drivers/media/radio/radio-cadet.c
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@ -270,6 +270,16 @@ reset_rds:
outb(inb(dev->io + 1) & 0x7f, dev->io + 1);
}
static bool cadet_has_rds_data(struct cadet *dev)
{
bool result;
mutex_lock(&dev->lock);
result = dev->rdsin != dev->rdsout;
mutex_unlock(&dev->lock);
return result;
}
static void cadet_handler(unsigned long data)
{
@ -279,13 +289,12 @@ static void cadet_handler(unsigned long data)
if (mutex_trylock(&dev->lock)) {
outb(0x3, dev->io); /* Select RDS Decoder Control */
if ((inb(dev->io + 1) & 0x20) != 0)
printk(KERN_CRIT "cadet: RDS fifo overflow\n");
pr_err("cadet: RDS fifo overflow\n");
outb(0x80, dev->io); /* Select RDS fifo */
while ((inb(dev->io) & 0x80) != 0) {
dev->rdsbuf[dev->rdsin] = inb(dev->io + 1);
if (dev->rdsin + 1 == dev->rdsout)
printk(KERN_WARNING "cadet: RDS buffer overflow\n");
else
if (dev->rdsin + 1 != dev->rdsout)
dev->rdsin++;
}
mutex_unlock(&dev->lock);
@ -294,7 +303,7 @@ static void cadet_handler(unsigned long data)
/*
* Service pending read
*/
if (dev->rdsin != dev->rdsout)
if (cadet_has_rds_data(dev))
wake_up_interruptible(&dev->read_queue);
/*
@ -327,22 +336,21 @@ static ssize_t cadet_read(struct file *file, char __user *data, size_t count, lo
mutex_lock(&dev->lock);
if (dev->rdsstat == 0)
cadet_start_rds(dev);
if (dev->rdsin == dev->rdsout) {
if (file->f_flags & O_NONBLOCK) {
i = -EWOULDBLOCK;
goto unlock;
}
mutex_unlock(&dev->lock);
interruptible_sleep_on(&dev->read_queue);
mutex_lock(&dev->lock);
}
mutex_unlock(&dev->lock);
if (!cadet_has_rds_data(dev) && (file->f_flags & O_NONBLOCK))
return -EWOULDBLOCK;
i = wait_event_interruptible(dev->read_queue, cadet_has_rds_data(dev));
if (i)
return i;
mutex_lock(&dev->lock);
while (i < count && dev->rdsin != dev->rdsout)
readbuf[i++] = dev->rdsbuf[dev->rdsout++];
mutex_unlock(&dev->lock);
if (i && copy_to_user(data, readbuf, i))
i = -EFAULT;
unlock:
mutex_unlock(&dev->lock);
return -EFAULT;
return i;
}
@ -352,7 +360,7 @@ static int vidioc_querycap(struct file *file, void *priv,
{
strlcpy(v->driver, "ADS Cadet", sizeof(v->driver));
strlcpy(v->card, "ADS Cadet", sizeof(v->card));
strlcpy(v->bus_info, "ISA", sizeof(v->bus_info));
strlcpy(v->bus_info, "ISA:radio-cadet", sizeof(v->bus_info));
v->device_caps = V4L2_CAP_TUNER | V4L2_CAP_RADIO |
V4L2_CAP_READWRITE | V4L2_CAP_RDS_CAPTURE;
v->capabilities = v->device_caps | V4L2_CAP_DEVICE_CAPS;
@ -491,7 +499,7 @@ static unsigned int cadet_poll(struct file *file, struct poll_table_struct *wait
cadet_start_rds(dev);
mutex_unlock(&dev->lock);
}
if (dev->rdsin != dev->rdsout)
if (cadet_has_rds_data(dev))
res |= POLLIN | POLLRDNORM;
return res;
}