• Ming Lei's avatar
    block: free sched's request pool in blk_cleanup_queue · c3e22192
    Ming Lei authored
    In theory, IO scheduler belongs to request queue, and the request pool
    of sched tags belongs to the request queue too.
    
    However, the current tags allocation interfaces are re-used for both
    driver tags and sched tags, and driver tags is definitely host wide,
    and doesn't belong to any request queue, same with its request pool.
    So we need tagset instance for freeing request of sched tags.
    
    Meantime, blk_mq_free_tag_set() often follows blk_cleanup_queue() in case
    of non-BLK_MQ_F_TAG_SHARED, this way requires that request pool of sched
    tags to be freed before calling blk_mq_free_tag_set().
    
    Commit 47cdee29 ("block: move blk_exit_queue into __blk_release_queue")
    moves blk_exit_queue into __blk_release_queue for simplying the fast
    path in generic_make_request(), then causes oops during freeing requests
    of sched tags in __blk_release_queue().
    
    Fix the above issue by move freeing request pool of sched tags into
    blk_cleanup_queue(), this way is safe becasue queue has been frozen and no any
    in-queue requests at that time. Freeing sched tags has to be kept in queue's
    release handler becasue there might be un-completed dispatch activity
    which might refer to sched tags.
    
    Cc: Bart Van Assche <bvanassche@acm.org>
    Cc: Christoph Hellwig <hch@lst.de>
    Fixes: 47cdee29 ("block: move blk_exit_queue into __blk_release_queue")
    Tested-by: default avatarYi Zhang <yi.zhang@redhat.com>
    Reported-by: default avatarkernel test robot <rong.a.chen@intel.com>
    Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
    Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
    c3e22192
blk.h 10.2 KB