When user tries to replace the user-defined control TLV, the kernel
checks the change of its content via memcmp(). The problem is that
the kernel passes the return value from memcmp() as is. memcmp()
gives a non-zero negative value depending on the comparison result,
and this shall be recognized as an error code.
The patch covers that corner-case, return 1 properly for the changed
TLV.
Fixes: 8aa9b586e4 ("[ALSA] Control API - more robust TLV implementation")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
88c54cdf61