• FUJITA Tomonori's avatar
    block: move cmdfilter from gendisk to request_queue · abf54393
    FUJITA Tomonori authored
    cmd_filter works only for the block layer SG_IO with SCSI block
    devices. It breaks scsi/sg.c, bsg, and the block layer SG_IO with SCSI
    character devices (such as st). We hit a kernel crash with them.
    
    The problem is that cmd_filter code accesses to gendisk (having struct
    blk_scsi_cmd_filter) via inode->i_bdev->bd_disk. It works for only
    SCSI block device files. With character device files, inode->i_bdev
    leads you to struct cdev. inode->i_bdev->bd_disk->blk_scsi_cmd_filter
    isn't safe.
    
    SCSI ULDs don't expose gendisk; they keep it private. bsg needs to be
    independent on any protocols. We shouldn't change ULDs to expose their
    gendisk.
    
    This patch moves struct blk_scsi_cmd_filter from gendisk to
    request_queue, a common object, which eveyone can access to.
    
    The user interface doesn't change; users can change the filters via
    /sys/block/. gendisk has a pointer to request_queue so the cmd_filter
    code accesses to struct blk_scsi_cmd_filter.
    Signed-off-by: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
    Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
    abf54393
bsg.c 23 KB