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scsi: atari_scsi: Fix race condition between .queuecommand and EH 

It is possible that bus_reset_cleanup() or .eh_abort_handler could be
invoked during NCR5380_queuecommand(). If that takes place before the new
command is enqueued and after the ST-DMA "lock" has been acquired, the
ST-DMA "lock" will be released again. This will result in a lost DMA
interrupt and a command timeout. Fix this by excluding EH and interrupt
handlers while the new command is enqueued.

Link: https://lore.kernel.org/r/af25163257796b50bb99d4ede4025cea55787b8f.1605847196.git.fthain@telegraphics.com.au
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
zero-sugar-mainline-defconfig
Finn Thain 2020-11-20 15:39:56 +11:00 committed by Martin K. Petersen
parent 66df79ccbc
commit 03fe6a640a
2 changed files with 9 additions and 10 deletions
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9
drivers/scsi/NCR5380.c
View File

@ -580,11 +580,14 @@ static int NCR5380_queue_command(struct Scsi_Host *instance,
cmd->result = 0;
if (!NCR5380_acquire_dma_irq(instance))
return SCSI_MLQUEUE_HOST_BUSY;
spin_lock_irqsave(&hostdata->lock, flags);
if (!NCR5380_acquire_dma_irq(instance)) {
spin_unlock_irqrestore(&hostdata->lock, flags);
return SCSI_MLQUEUE_HOST_BUSY;
}
/*
* Insert the cmd into the issue queue. Note that REQUEST SENSE
* commands are added to the head of the queue since any command will

10
drivers/scsi/atari_scsi.c
View File

@ -376,15 +376,11 @@ static int falcon_get_lock(struct Scsi_Host *instance)
if (IS_A_TT())
return 1;
if (stdma_is_locked_by(scsi_falcon_intr) &&
instance->hostt->can_queue > 1)
if (stdma_is_locked_by(scsi_falcon_intr))
return 1;
if (in_interrupt())
return stdma_try_lock(scsi_falcon_intr, instance);
stdma_lock(scsi_falcon_intr, instance);
return 1;
/* stdma_lock() may sleep which means it can't be used here */
return stdma_try_lock(scsi_falcon_intr, instance);
}
#ifndef MODULE