• Arjan van de Ven's avatar
    driver synchronization: make scsi_wait_scan more advanced · d4d5291c
    Arjan van de Ven authored
    There is currently only one way for userspace to say "wait for my storage
    device to get ready for the modules I just loaded": to load the
    scsi_wait_scan module. Expectations of userspace are that once this
    module is loaded, all the (storage) devices for which the drivers
    were loaded before the module load are present.
    
    Now, there are some issues with the implementation, and the async
    stuff got caught in the middle of this: The existing code only
    waits for the scsy async probing to finish, but it did not take
    into account at all that probing might not have begun yet.
    (Russell ran into this problem on his computer and the fix works for him)
    
    This patch fixes this more thoroughly than the previous "fix", which
    had some bad side effects (namely, for kernel code that wanted to wait for
    the scsi scan it would also do an async sync, which would deadlock if you did
    it from async context already.. there's a report about that on lkml):
    The patch makes the module first wait for all device driver probes, and then it
    will wait for the scsi parallel scan to finish.
    Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
    Tested-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    d4d5291c
scsi_scan.c 53.9 KB