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    mmc: fix all hangs related to mmc/sd card insert/removal during suspend/resume · 4c2ef25f
    Maxim Levitsky 提交于
    If you don't use CONFIG_MMC_UNSAFE_RESUME, as soon as you attempt to
    suspend, the card will be removed, therefore this patch doesn't change the
    behavior of this option.
    
    However the removal will be done by pm notifier, which runs while
    userspace is still not frozen and thus can freely use del_gendisk, without
    the risk of deadlock which would happen otherwise.
    
    Card detect workqueue is now disabled while userspace is frozen, Therefore
    if you do use CONFIG_MMC_UNSAFE_RESUME, and remove the card during
    suspend, the removal will be detected as soon as userspace is unfrozen,
    again at the moment it is safe to call del_gendisk.
    
    Tested with and without CONFIG_MMC_UNSAFE_RESUME with suspend and hibernate.
    
    [akpm@linux-foundation.org: clean up function prototype]
    [akpm@linux-foundation.org: fix CONFIG_PM-n linkage, small cleanups]
    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
    Cc: David Brownell <david-b@pacbell.net>
    Cc: Alan Stern <stern@rowland.harvard.edu>
    Cc: <linux-mmc@vger.kernel.org>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    4c2ef25f
core.c 31.3 KB