16b29e75a7
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>
22 lines
475 B
C
22 lines
475 B
C
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#ifndef _atari_stdma_h
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#define _atari_stdma_h
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#include <linux/interrupt.h>
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/***************************** Prototypes *****************************/
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int stdma_try_lock(irq_handler_t, void *);
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void stdma_lock(irq_handler_t handler, void *data);
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void stdma_release( void );
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int stdma_islocked( void );
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int stdma_is_locked_by(irq_handler_t);
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void stdma_init( void );
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/************************* End of Prototypes **************************/
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#endif /* _atari_stdma_h */
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