Re: [PATCH] dabusb: remove the BKL

2010-10-15 Thread Mauro Carvalho Chehab
Em 04-10-2010 16:32, Arnd Bergmann escreveu:
> The dabusb device driver is sufficiently serialized using
> its own mutex, no need for the big kernel lock here
> in addition.
> 
> Signed-off-by: Arnd Bergmann 
> Cc: Mauro Carvalho Chehab 
> ---
> 
> Hi Mauro,
> 
> I just realized that the dabusb driver is not actually a v4l driver,
> when I did more test builds with allyesconfig and CONFIG_BKL disabled.
> 
> I've added this patch to my bkl/config queue for now, but if you want to carry
> it in your tree, I'll drop it from mine.

Sorry for not handling it sooner... I have a large number of patches in my 
queue...
I don't have any patch for dabusb on my tree, so, I'm OK if you sent it via your
tree. So,

Acked-by: Mauro Carvalho Chehab 

---

PS.: I tried to contact the authors a few weeks ago to double check about this 
driver.
I suspect that it were added for some prototype, based on its help message, and 
the
links I found about that. So, it could be a good idea to simply move it to 
staging
and let it die, as maybe nobody has an actual hardware for it... 
Well, I got no answer about that so far.

> 
> diff --git a/drivers/media/video/dabusb.c b/drivers/media/video/dabusb.c
> index 5b176bd..f3e25e9 100644
> --- a/drivers/media/video/dabusb.c
> +++ b/drivers/media/video/dabusb.c
> @@ -32,7 +32,6 @@
>  #include 
>  #include 
>  #include 
> -#include 
>  #include 
>  #include 
>  #include 
> @@ -621,7 +620,6 @@ static int dabusb_open (struct inode *inode, struct file 
> *file)
>   if (devnum < DABUSB_MINOR || devnum >= (DABUSB_MINOR + NRDABUSB))
>   return -EIO;
>  
> - lock_kernel();
>   s = &dabusb[devnum - DABUSB_MINOR];
>  
>   dbg("dabusb_open");
> @@ -630,21 +628,17 @@ static int dabusb_open (struct inode *inode, struct 
> file *file)
>   while (!s->usbdev || s->opened) {
>   mutex_unlock(&s->mutex);
>  
> - if (file->f_flags & O_NONBLOCK) {
> + if (file->f_flags & O_NONBLOCK)
>   return -EBUSY;
> - }
>   msleep_interruptible(500);
>  
> - if (signal_pending (current)) {
> - unlock_kernel();
> + if (signal_pending (current))
>   return -EAGAIN;
> - }
>   mutex_lock(&s->mutex);
>   }
>   if (usb_set_interface (s->usbdev, _DABUSB_IF, 1) < 0) {
>   mutex_unlock(&s->mutex);
>   dev_err(&s->usbdev->dev, "set_interface failed\n");
> - unlock_kernel();
>   return -EINVAL;
>   }
>   s->opened = 1;
> @@ -654,7 +648,6 @@ static int dabusb_open (struct inode *inode, struct file 
> *file)
>   file->private_data = s;
>  
>   r = nonseekable_open(inode, file);
> - unlock_kernel();
>   return r;
>  }
>  
> @@ -689,17 +682,13 @@ static long dabusb_ioctl (struct file *file, unsigned 
> int cmd, unsigned long arg
>  
>   dbg("dabusb_ioctl");
>  
> - lock_kernel();
> - if (s->remove_pending) {
> - unlock_kernel();
> + if (s->remove_pending)
>   return -EIO;
> - }
>  
>   mutex_lock(&s->mutex);
>  
>   if (!s->usbdev) {
>   mutex_unlock(&s->mutex);
> - unlock_kernel();
>   return -EIO;
>   }
>  
> @@ -735,7 +724,6 @@ static long dabusb_ioctl (struct file *file, unsigned int 
> cmd, unsigned long arg
>   break;
>   }
>   mutex_unlock(&s->mutex);
> - unlock_kernel();
>   return ret;
>  }
>  

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[PATCH] dabusb: remove the BKL

2010-10-04 Thread Arnd Bergmann
The dabusb device driver is sufficiently serialized using
its own mutex, no need for the big kernel lock here
in addition.

Signed-off-by: Arnd Bergmann 
Cc: Mauro Carvalho Chehab 
---

Hi Mauro,

I just realized that the dabusb driver is not actually a v4l driver,
when I did more test builds with allyesconfig and CONFIG_BKL disabled.

I've added this patch to my bkl/config queue for now, but if you want to carry
it in your tree, I'll drop it from mine.

diff --git a/drivers/media/video/dabusb.c b/drivers/media/video/dabusb.c
index 5b176bd..f3e25e9 100644
--- a/drivers/media/video/dabusb.c
+++ b/drivers/media/video/dabusb.c
@@ -32,7 +32,6 @@
 #include 
 #include 
 #include 
-#include 
 #include 
 #include 
 #include 
@@ -621,7 +620,6 @@ static int dabusb_open (struct inode *inode, struct file 
*file)
if (devnum < DABUSB_MINOR || devnum >= (DABUSB_MINOR + NRDABUSB))
return -EIO;
 
-   lock_kernel();
s = &dabusb[devnum - DABUSB_MINOR];
 
dbg("dabusb_open");
@@ -630,21 +628,17 @@ static int dabusb_open (struct inode *inode, struct file 
*file)
while (!s->usbdev || s->opened) {
mutex_unlock(&s->mutex);
 
-   if (file->f_flags & O_NONBLOCK) {
+   if (file->f_flags & O_NONBLOCK)
return -EBUSY;
-   }
msleep_interruptible(500);
 
-   if (signal_pending (current)) {
-   unlock_kernel();
+   if (signal_pending (current))
return -EAGAIN;
-   }
mutex_lock(&s->mutex);
}
if (usb_set_interface (s->usbdev, _DABUSB_IF, 1) < 0) {
mutex_unlock(&s->mutex);
dev_err(&s->usbdev->dev, "set_interface failed\n");
-   unlock_kernel();
return -EINVAL;
}
s->opened = 1;
@@ -654,7 +648,6 @@ static int dabusb_open (struct inode *inode, struct file 
*file)
file->private_data = s;
 
r = nonseekable_open(inode, file);
-   unlock_kernel();
return r;
 }
 
@@ -689,17 +682,13 @@ static long dabusb_ioctl (struct file *file, unsigned int 
cmd, unsigned long arg
 
dbg("dabusb_ioctl");
 
-   lock_kernel();
-   if (s->remove_pending) {
-   unlock_kernel();
+   if (s->remove_pending)
return -EIO;
-   }
 
mutex_lock(&s->mutex);
 
if (!s->usbdev) {
mutex_unlock(&s->mutex);
-   unlock_kernel();
return -EIO;
}
 
@@ -735,7 +724,6 @@ static long dabusb_ioctl (struct file *file, unsigned int 
cmd, unsigned long arg
break;
}
mutex_unlock(&s->mutex);
-   unlock_kernel();
return ret;
 }
 
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