tree 72671e9cad1d1fa6acadd7e389515f3579f3ff26
parent 7090a0a97f55cbf47547a140fcc5a349f32c598c
author Tejun Heo <tj@kernel.org> 1240889913 +0900
committer Jens Axboe <jens.axboe@oracle.com> 1240897016 +0200

hd: fix locking

hd dance around local irq and HD_IRQ enable without achieving much.
It ends up transferring data from irq handler with both local irq and
HD_IRQ disabled.  The only place it actually does something is while
transferring the first block of a request which it does with HD_IRQ
disabled but local irq enabled.

Unfortunately, the dancing is horribly broken from locking POV.  IRQ
and timeout handlers access block queue without grabbing the queue
lock and running the driver in SMP configuration crashes the whole
machine pretty quickly.

Remove meaningless irq enable/disable dancing and add proper locking
in issue, irq and timeout paths.

Signed-off-by: Tejun Heo <tj@kernel.org>