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| author | Christoph Hellwig <hch@lst.de> | 2014-01-23 12:07:41 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-07-25 23:15:48 +0200 |
| commit | cd9070c9c512ff7995f9019392e0ae548df3a088 (patch) | |
| tree | a426fccd5633f429f37dac237d8cf417ad9e7f31 /samples/hw_breakpoint | |
| parent | scsi: convert device_busy to atomic_t (diff) | |
| download | linux-cd9070c9c512ff7995f9019392e0ae548df3a088.tar.xz linux-cd9070c9c512ff7995f9019392e0ae548df3a088.zip | |
scsi: fix the {host,target,device}_blocked counter mess
Seems like these counters are missing any sort of synchronization for
updates, as a over 10 year old comment from me noted. Fix this by
using atomic counters, and while we're at it also make sure they are
in the same cacheline as the _busy counters and not needlessly stored
to in every I/O completion.
With the new model the _busy counters can temporarily go negative,
so all the readers are updated to check for > 0 values. Longer
term every successful I/O completion will reset the counters to zero,
so the temporarily negative values will not cause any harm.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.com>
Diffstat (limited to 'samples/hw_breakpoint')
0 files changed, 0 insertions, 0 deletions