• Richard Fitzgerald's avatar
    soundwire: bus: Fix unbalanced pm_runtime_put() causing usage count underflow · e9537962
    Richard Fitzgerald authored
    This reverts commit
    443a98e6 ("soundwire: bus: use pm_runtime_resume_and_get()")
    
    Change calls to pm_runtime_resume_and_get() back to pm_runtime_get_sync().
    This fixes a usage count underrun caused by doing a pm_runtime_put() even
    though pm_runtime_resume_and_get() returned an error.
    
    The three affected functions ignore -EACCES error from trying to get
    pm_runtime, and carry on, including a put at the end of the function.
    But pm_runtime_resume_and_get() does not increment the usage count if it
    returns an error. So in the -EACCES case you must not call
    pm_runtime_put().
    
    The documentation for pm_runtime_get_sync() says:
     "Consider using pm_runtime_resume_and_get() ...  as this is likely to
     result in cleaner code."
    
    In this case I don't think it results in cleaner code because the
    pm_runtime_put() at the end of the function would have to be conditional on
    the return value from pm_runtime_resume_and_get() at the top of the
    function.
    
    pm_runtime_get_sync() doesn't have this problem because it always
    increments the count, so always needs a put. The code can just flow through
    and do the pm_runtime_put() unconditionally.
    Signed-off-by: default avatarRichard Fitzgerald <rf@opensource.cirrus.com>
    Reviewed-by: default avatarPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
    Link: https://lore.kernel.org/r/20230406134640.8582-1-rf@opensource.cirrus.comSigned-off-by: default avatarVinod Koul <vkoul@kernel.org>
    e9537962
bus.c 48 KB