1. 24 May, 2023 37 commits
  2. 23 May, 2023 2 commits
    • Yu Kuai's avatar
      block/rq_qos: protect rq_qos apis with a new lock · a13bd91b
      Yu Kuai authored
      commit 50e34d78 ("block: disable the elevator int del_gendisk")
      move rq_qos_exit() from disk_release() to del_gendisk(), this will
      introduce some problems:
      
      1) If rq_qos_add() is triggered by enabling iocost/iolatency through
         cgroupfs, then it can concurrent with del_gendisk(), it's not safe to
         write 'q->rq_qos' concurrently.
      
      2) Activate cgroup policy that is relied on rq_qos will call
         rq_qos_add() and blkcg_activate_policy(), and if rq_qos_exit() is
         called in the middle, null-ptr-dereference will be triggered in
         blkcg_activate_policy().
      
      3) blkg_conf_open_bdev() can call blkdev_get_no_open() first to find the
         disk, then if rq_qos_exit() from del_gendisk() is done before
         rq_qos_add(), then memory will be leaked.
      
      This patch add a new disk level mutex 'rq_qos_mutex':
      
      1) The lock will protect rq_qos_exit() directly.
      
      2) For wbt that doesn't relied on blk-cgroup, rq_qos_add() can only be
         called from disk initialization for now because wbt can't be
         destructed until rq_qos_exit(), so it's safe not to protect wbt for
         now. Hoever, in case that rq_qos dynamically destruction is supported
         in the furture, this patch also protect rq_qos_add() from wbt_init()
         directly, this is enough because blk-sysfs already synchronize
         writers with disk removal.
      
      3) For iocost and iolatency, in order to synchronize disk removal and
         cgroup configuration, the lock is held after blkdev_get_no_open()
         from blkg_conf_open_bdev(), and is released in blkg_conf_exit().
         In order to fix the above memory leak, disk_live() is checked after
         holding the new lock.
      
      Fixes: 50e34d78 ("block: disable the elevator int del_gendisk")
      Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Link: https://lore.kernel.org/r/20230414084008.2085155-1-yukuai1@huaweicloud.comSigned-off-by: default avatarJens Axboe <axboe@kernel.dk>
      a13bd91b
    • Li Nan's avatar
      block: remove redundant req_op in blk_rq_is_passthrough · 712fd23a
      Li Nan authored
      op &= REQ_OP_MASK in blk_op_is_passthrough() is exactly what req_op() do.
      Therefore, it is redundant to call req_op() for blk_op_is_passthrough().
      Signed-off-by: default avatarLi Nan <linan122@huawei.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
      Link: https://lore.kernel.org/r/20230522085355.1740772-1-linan666@huaweicloud.comSigned-off-by: default avatarJens Axboe <axboe@kernel.dk>
      712fd23a
  3. 21 May, 2023 1 commit