• Jens Axboe's avatar
    [BLOCK] limit request_fn recursion · dac07ec1
    Jens Axboe authored
    Don't recurse back into the driver even if the unplug threshold is met,
    when the driver asks for a requeue. This is both silly from a logical
    point of view (requeues typically happen due to driver/hardware
    shortage), and also dangerous since we could hit an endless request_fn
    -> requeue -> unplug -> request_fn loop and crash on stack overrun.
    
    Also limit blk_run_queue() to one level of recursion, similar to how
    blk_start_queue() works.
    
    This patch fixed a real problem with SLES10 and lpfc, and it could hit
    any SCSI lld that returns non-zero from it's ->queuecommand() handler.
    Signed-off-by: default avatarJens Axboe <axboe@suse.de>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    dac07ec1
ll_rw_blk.c 98.9 KB