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 /drivers/scsi/atari_NCR5380.c | |
parent | cbad48deb38d8e442db9760ca1f950cd24429707 (diff) | |
download | linux-16b29e75a78ae03250233468b68f7ae467d3dc7a.tar.bz2 |
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 'drivers/scsi/atari_NCR5380.c')
-rw-r--r-- | drivers/scsi/atari_NCR5380.c | 33 |
1 files changed, 10 insertions, 23 deletions
diff --git a/drivers/scsi/atari_NCR5380.c b/drivers/scsi/atari_NCR5380.c index 4eeb9684977b..7a6f90ce0316 100644 --- a/drivers/scsi/atari_NCR5380.c +++ b/drivers/scsi/atari_NCR5380.c @@ -879,10 +879,10 @@ static void NCR5380_exit(struct Scsi_Host *instance) * */ -static int NCR5380_queue_command_lck(struct scsi_cmnd *cmd, - void (*done)(struct scsi_cmnd *)) +static int NCR5380_queue_command(struct Scsi_Host *instance, + struct scsi_cmnd *cmd) { - SETUP_HOSTDATA(cmd->device->host); + struct NCR5380_hostdata *hostdata = shost_priv(instance); struct scsi_cmnd *tmp; unsigned long flags; @@ -893,7 +893,7 @@ static int NCR5380_queue_command_lck(struct scsi_cmnd *cmd, printk(KERN_NOTICE "scsi%d: WRITE attempted with NO_WRITE debugging flag set\n", H_NO(cmd)); cmd->result = (DID_ERROR << 16); - done(cmd); + cmd->scsi_done(cmd); return 0; } #endif /* (NDEBUG & NDEBUG_NO_WRITE) */ @@ -904,8 +904,6 @@ static int NCR5380_queue_command_lck(struct scsi_cmnd *cmd, */ SET_NEXT(cmd, NULL); - cmd->scsi_done = done; - cmd->result = 0; /* @@ -915,7 +913,6 @@ static int NCR5380_queue_command_lck(struct scsi_cmnd *cmd, * sense data is only guaranteed to be valid while the condition exists. */ - local_irq_save(flags); /* ++guenther: now that the issue queue is being set up, we can lock ST-DMA. * Otherwise a running NCR5380_main may steal the lock. * Lock before actually inserting due to fairness reasons explained in @@ -928,11 +925,11 @@ static int NCR5380_queue_command_lck(struct scsi_cmnd *cmd, * because also a timer int can trigger an abort or reset, which would * alter queues and touch the lock. */ - if (!IS_A_TT()) { - /* perhaps stop command timer here */ - falcon_get_lock(); - /* perhaps restart command timer here */ - } + if (!falcon_get_lock()) + return SCSI_MLQUEUE_HOST_BUSY; + + local_irq_save(flags); + if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) { LIST(cmd, hostdata->issue_queue); SET_NEXT(cmd, hostdata->issue_queue); @@ -956,15 +953,13 @@ static int NCR5380_queue_command_lck(struct scsi_cmnd *cmd, * If we're not in an interrupt, we can call NCR5380_main() * unconditionally, because it cannot be already running. */ - if (in_interrupt() || ((flags >> 8) & 7) >= 6) + if (in_interrupt() || irqs_disabled()) queue_main(); else NCR5380_main(NULL); return 0; } -static DEF_SCSI_QCMD(NCR5380_queue_command) - /* * Function : NCR5380_main (void) * @@ -2554,10 +2549,6 @@ int NCR5380_abort(struct scsi_cmnd *cmd) local_irq_save(flags); - if (!IS_A_TT() && !falcon_got_lock) - printk(KERN_ERR "scsi%d: !!BINGO!! Falcon has no lock in NCR5380_abort\n", - HOSTNO); - dprintk(NDEBUG_ABORT, "scsi%d: abort called basr 0x%02x, sr 0x%02x\n", HOSTNO, NCR5380_read(BUS_AND_STATUS_REG), NCR5380_read(STATUS_REG)); @@ -2756,10 +2747,6 @@ static int NCR5380_bus_reset(struct scsi_cmnd *cmd) struct scsi_cmnd *connected, *disconnected_queue; #endif - if (!IS_A_TT() && !falcon_got_lock) - printk(KERN_ERR "scsi%d: !!BINGO!! Falcon has no lock in NCR5380_reset\n", - H_NO(cmd)); - NCR5380_print_status(cmd->device->host); /* get in phase */ |