diff options
| author | Finn Thain <fthain@telegraphics.com.au> | 2014-11-12 16:12:08 +1100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-11-20 09:11:13 +0100 |
| commit | 16b29e75a78ae03250233468b68f7ae467d3dc7a (patch) | |
| tree | a5ba9e016d5557d2a6f5fb60dc83ae906ae771af /arch/m68k/include | |
| parent | cbad48deb38d8e442db9760ca1f950cd24429707 (diff) | |
atari_scsi: Fix atari_scsi deadlocks on Falcon
Don't disable irqs when waiting for the ST DMA "lock"; its release may
require an interrupt.
Introduce stdma_try_lock() for use in soft irq context. atari_scsi now tells
the SCSI mid-layer to defer queueing a command if the ST DMA lock is not
available, as per Michael's patch:
http://marc.info/?l=linux-m68k&m=139095335824863&w=2
The falcon_got_lock variable is race prone: we can't disable IRQs while
waiting to acquire the lock, so after acquiring it there must be some
interval during which falcon_got_lock remains false. Introduce
stdma_is_locked_by() to replace falcon_got_lock.
The falcon_got_lock tests in the EH handlers are incorrect these days. It
can happen that an EH handler is called after a command completes normally.
Remove these checks along with falcon_got_lock.
Also remove the complicated and racy fairness wait queues. If fairness is an
issue (when SCSI competes with IDE for the ST DMA interrupt), the solution
is likely to be a lower value for host->can_queue.
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'arch/m68k/include')
| -rw-r--r-- | arch/m68k/include/asm/atari_stdma.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/m68k/include/asm/atari_stdma.h b/arch/m68k/include/asm/atari_stdma.h index 8e389b7fa70c..d24e34d870dc 100644 --- a/arch/m68k/include/asm/atari_stdma.h +++ b/arch/m68k/include/asm/atari_stdma.h @@ -8,11 +8,11 @@ /***************************** Prototypes *****************************/ +int stdma_try_lock(irq_handler_t, void *); void stdma_lock(irq_handler_t handler, void *data); void stdma_release( void ); -int stdma_others_waiting( void ); int stdma_islocked( void ); -void *stdma_locked_by( void ); +int stdma_is_locked_by(irq_handler_t); void stdma_init( void ); /************************* End of Prototypes **************************/ |