>
>Justin,
>When free memory is low, I get a series of aic7xxx messages followed by
>panic. It appears to be a race condition in the code.
Its actually a logic error, not a race condition. You should never
enter ahc_linux_run_device_queue() while the device is still on the
run queue. The real issue is that ahc_linux_queue bypasses the
round-robin device scheduler by calling ahc_linux_run_device_queue()
directly. The code should look like this (the LIST macro calls
where switched to TAILQ calls a bit ago to ensure round-robin, but
that change came just after 6.1.13). I haven't tested this yet...
Thanks for the bug report. If you can verify that this works under
memeory pressure, the printf can go away.
--
Justin
==== //depot/src/linux/drivers/scsi/aic7xxx/aic7xxx_linux.c#67 -
/usr/src/linux/drivers/scsi/aic7xxx/aic7xxx_linux.c ====
--- /tmp/tmp.3288.0 Tue Jun 19 11:07:32 2001
+++ /usr/src/linux/drivers/scsi/aic7xxx/aic7xxx_linux.c Tue Jun 19 11:02:54 2001
@@ -1514,7 +1514,11 @@
}
cmd->result = CAM_REQ_INPROG << 16;
TAILQ_INSERT_TAIL(&dev->busyq, (struct ahc_cmd *)cmd, acmd_links.tqe);
- ahc_linux_run_device_queue(ahc, dev);
+ if ((dev->flags & AHC_DEV_ON_RUN_LIST) == 0) {
+ TAILQ_INSERT_TAIL(&ahc->platform_data->device_runq, dev, links);
+ dev->flags |= AHC_DEV_ON_RUN_LIST;
+ ahc_linux_run_device_queues(ahc);
+ }
ahc_unlock(ahc, &flags);
return (0);
}
@@ -1530,6 +1534,9 @@
struct ahc_tmode_tstate *tstate;
uint16_t mask;
+ if ((dev->flags & AHC_DEV_ON_RUN_LIST) != 0)
+ panic("running device on run list");
+
while ((acmd = TAILQ_FIRST(&dev->busyq)) != NULL
&& dev->openings > 0 && dev->qfrozen == 0) {
@@ -1538,8 +1545,6 @@
* running is because the whole controller Q is frozen.
*/
if (ahc->platform_data->qfrozen != 0) {
- if ((dev->flags & AHC_DEV_ON_RUN_LIST) != 0)
- return;
TAILQ_INSERT_TAIL(&ahc->platform_data->device_runq,
dev, links);
@@ -1550,8 +1555,6 @@
* Get an scb to use.
*/
if ((scb = ahc_get_scb(ahc)) == NULL) {
- if ((dev->flags & AHC_DEV_ON_RUN_LIST) != 0)
- panic("running device on run list");
TAILQ_INSERT_TAIL(&ahc->platform_data->device_runq,
dev, links);
dev->flags |= AHC_DEV_ON_RUN_LIST;
-
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