[PATCH] Fix SMP support on cdu535 cdrom driver

[PATCH] Fix SMP support on cdu535 cdrom driver

[Felipe W Damasio]

[-- Attachment #1: Type: text/plain, Size: 408 bytes --]

	Hi,

	Patch against 2.6-test4.

	I'm not sure this is the right fix, since my knowledge on cdrom 
drivers tends to /dev/zero...but, here we go:

	Replace cli/sti on sony_sleep with wait_queue, using a device 
spinlock to lock 'enable_interrupts' and the queueing stuff.

	Compile fine, but I don't have the hardware.

	Feedback is welcome, since I'm pretty sure I did something wrong.. :)

	Thanks,

Felipe

[-- Attachment #2: cdu535-cli_sti_removal.patch --]
[-- Type: text/plain, Size: 1429 bytes --]

--- linux-2.6.0-test4/drivers/cdrom/sonycd535.c	Fri Aug 22 20:54:17 2003
+++ linux-2.6.0-test4-fwd/drivers/cdrom/sonycd535.c	Tue Sep  2 18:24:10 2003
@@ -36,6 +36,10 @@
  *	            module_init & module_exit.
  *                  Torben Mathiasen <tmm@image.dk>
  *
+ * September 2003 - Fix SMP support by removing cli/sti calls.
+ *                  Using spinlocks with a wait_queue instead
+ *                  Felipe Damasio <felipewd@terra.com.br>
+ *
  * Things to do:
  *  - handle errors and status better, put everything into a single word
  *  - use interrupts (code mostly there, but a big hole still missing)
@@ -219,6 +223,9 @@
 static unsigned short data_reg;
 
 static spinlock_t sonycd535_lock = SPIN_LOCK_UNLOCKED; /* queue lock */
+
+static spinlock_t cdu535_lock = SPIN_LOCK_UNLOCKED;  /* Device lock */
+
 static struct request_queue *sonycd535_queue;
 
 static int initialized;			/* Has the drive been initialized? */
@@ -340,10 +347,16 @@
 	if (sony535_irq_used <= 0) {	/* poll */
 		yield();
 	} else {	/* Interrupt driven */
-		cli();
+		DEFINE_WAIT(wait);
+		
+		spin_lock_irq(&cdu535_lock);
 		enable_interrupts();
-		interruptible_sleep_on(&cdu535_irq_wait);
-		sti();
+		prepare_to_wait(&cdu535_irq_wait, &wait, TASK_INTERRUPTIBLE);
+		spin_unlock_irq(&cdu535_lock);
+		schedule();
+		spin_lock_irq(&cdu535_lock);
+		finish_wait(&cdu535_irq_wait, &wait);
+		spin_unlock_irq(&cdu535_lock);
 	}
 }
 

Re: [PATCH] Fix SMP support on cdu535 cdrom driver

[Felipe W Damasio]

Felipe W Damasio wrote:
>     Hi,
> 
>     Patch against 2.6-test4.
> 
>     I'm not sure this is the right fix, since my knowledge on cdrom 
> drivers tends to /dev/zero...but, here we go:
> 
>     Replace cli/sti on sony_sleep with wait_queue, using a device 
> spinlock to lock 'enable_interrupts' and the queueing stuff.

	Which it based from workqueue::flush_workqueue, but I don't know if 
the same algorithm applies to this block driver.

	Could someone with more experience on block drivers review this?

	Thanks.

Felipe