I
Hi Barto,
sorry for the late reply, and thanks for drilling down the exact
conditions.
I think we have some issues with the lack of the host lock vs error
handling, but I still don't undertand the details.
I've got a test patch for you that just adds the host lock back in a few
places while keeing the atomic_t. Can you try to reproduce with that
one?
When breaking an existing setup in software it's always the softwares
fault, btw..
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 994eb08..99b77f7 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -311,16 +311,16 @@ void scsi_device_unbusy(struct scsi_device *sdev)
struct scsi_target *starget = scsi_target(sdev);
unsigned long flags;
+ spin_lock_irqsave(shost->host_lock, flags);
atomic_dec(&shost->host_busy);
if (starget->can_queue > 0)
atomic_dec(&starget->target_busy);
if (unlikely(scsi_host_in_recovery(shost) &&
(shost->host_failed || shost->host_eh_scheduled))) {
- spin_lock_irqsave(shost->host_lock, flags);
scsi_eh_wakeup(shost);
- spin_unlock_irqrestore(shost->host_lock, flags);
}
+ spin_unlock_irqrestore(shost->host_lock, flags);
atomic_dec(&sdev->device_busy);
}
@@ -1504,6 +1504,8 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
if (scsi_host_in_recovery(shost))
return 0;
+ spin_lock_irq(shost->host_lock);
+
busy = atomic_inc_return(&shost->host_busy) - 1;
if (atomic_read(&shost->host_blocked) > 0) {
if (busy)
@@ -1527,21 +1529,19 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
/* We're OK to process the command, so we can't be starved */
if (!list_empty(&sdev->starved_entry)) {
- spin_lock_irq(shost->host_lock);
if (!list_empty(&sdev->starved_entry))
list_del_init(&sdev->starved_entry);
- spin_unlock_irq(shost->host_lock);
}
+ spin_unlock_irq(shost->host_lock);
return 1;
starved:
- spin_lock_irq(shost->host_lock);
if (list_empty(&sdev->starved_entry))
list_add_tail(&sdev->starved_entry, &shost->starved_list);
- spin_unlock_irq(shost->host_lock);
out_dec:
atomic_dec(&shost->host_busy);
+ spin_unlock_irq(shost->host_lock);
return 0;
}
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