ChangeSet 1.1730, 2004/05/17 11:38:40-07:00, oliver@neukum.org
[PATCH] USB: further fix to mdc800
I made a mistake fixing that driver. Here's the fix. Please apply soon.
- fix race condition leading to busy waiting
drivers/usb/image/mdc800.c | 33 +++++++++++++++++----------------
1 files changed, 17 insertions(+), 16 deletions(-)
diff -Nru a/drivers/usb/image/mdc800.c b/drivers/usb/image/mdc800.c
--- a/drivers/usb/image/mdc800.c Mon May 17 16:37:46 2004
+++ b/drivers/usb/image/mdc800.c Mon May 17 16:37:46 2004
@@ -33,7 +33,7 @@
* Fix: mdc800 used sleep_on and slept with io_lock held.
* Converted sleep_on to waitqueues with schedule_timeout and made io_lock
* a semaphore from a spinlock.
- * by Oliver Neukum <520047054719-0001@t-online.de>
+ * by Oliver Neukum <oliver@neukum.name>
* (02/12/2001)
*
* Identify version on module load.
@@ -41,7 +41,7 @@
*
* version 0.7.5
* Fixed potential SMP races with Spinlocks.
- * Thanks to Oliver Neukum <oliver.neukum@lrz.uni-muenchen.de> who
+ * Thanks to Oliver Neukum <oliver@neukum.name> who
* noticed the race conditions.
* (30/10/2000)
*
@@ -312,16 +312,17 @@
static int mdc800_usb_waitForIRQ (int mode, int msec)
{
DECLARE_WAITQUEUE(wait, current);
+ long timeout;
mdc800->camera_request_ready=1+mode;
add_wait_queue(&mdc800->irq_wait, &wait);
set_current_state(TASK_INTERRUPTIBLE);
- if (!mdc800->irq_woken)
+ timeout = msec*HZ/1000;
+ while (!mdc800->irq_woken && timeout)
{
- long timeout = msec*HZ/1000;
- while(timeout)
- timeout = schedule_timeout (timeout);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ timeout = schedule_timeout (timeout);
}
remove_wait_queue(&mdc800->irq_wait, &wait);
set_current_state(TASK_RUNNING);
@@ -670,6 +671,7 @@
{
size_t left=len, sts=len; /* single transfer size */
char* ptr=buf;
+ long timeout;
DECLARE_WAITQUEUE(wait, current);
down (&mdc800->io_lock);
@@ -717,12 +719,11 @@
return len-left;
}
add_wait_queue(&mdc800->download_wait, &wait);
- set_current_state(TASK_INTERRUPTIBLE);
- if (!mdc800->downloaded)
+ timeout = TO_DOWNLOAD_GET_READY*HZ/1000;
+ while (!mdc800->downloaded && timeout)
{
- long timeout = TO_DOWNLOAD_GET_READY*HZ/1000;
- while(timeout)
- timeout = schedule_timeout (timeout);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ timeout = schedule_timeout (timeout);
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&mdc800->download_wait, &wait);
@@ -823,6 +824,7 @@
if (mdc800->in_count == 8)
{
int answersize;
+ long timeout;
if (mdc800_usb_waitForIRQ (0,TO_GET_READY))
{
@@ -843,12 +845,11 @@
return -EIO;
}
add_wait_queue(&mdc800->write_wait, &wait);
- set_current_state(TASK_INTERRUPTIBLE);
- if (!mdc800->written)
+ timeout = TO_WRITE_GET_READY*HZ/1000;
+ while (!mdc800->written && timeout)
{
- long timeout = TO_WRITE_GET_READY*HZ/1000;
- while(timeout)
- timeout = schedule_timeout (timeout);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ timeout = schedule_timeout (timeout);
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&mdc800->write_wait, &wait);