ALSA: control: Take power_ref lock primarily

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The code path for kcontrol accesses have often nested locks of both
card's controls_rwsem and power_ref, and applies in that order.
However, what could take much longer is the latter, power_ref; it
waits for the power state of the device, and it pretty much depends on
the user's action.

This patch swaps the locking order of those locks to a more natural
way, namely, power_ref -> controls_rwsem, in order to shorten the time
of possible nested locks.  For consistency, power_ref is taken always
in the top-level caller side (that is, *_user() functions and the
ioctl handler itself).

Link: https://patch.msgid.link/20240729160659.4516-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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This commit is contained in:

Takashi Iwai 2024-07-29 18:06:58 +02:00

parent 3bb668264d

commit fcc62b1910

1 changed files with 34 additions and 20 deletions

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54

sound/core/control.c

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