[alsa-devel] [PATCH] ALSA: control: remove entry limitation for list operation

Takashi Sakamoto o-takashi at sakamocchi.jp
Wed May 24 03:04:30 CEST 2017


In current implementation of ALSA control core, list operation has
a limitation to handle 16384 entries at once. This seems due to
allocation in kernel space to copy data from user space.

With a commit 53e7bf452584 ("ALSA: control: Simplify snd_ctl_elem_list()
implementation"), for the operation, ALSA control core copies data
into user space directly. No need to care of kernel spaces anymore.

This commit purges the limitation.
---
 sound/core/control.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/sound/core/control.c b/sound/core/control.c
index 47080da8451a..ecd358213b83 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -757,9 +757,7 @@ static int snd_ctl_elem_list(struct snd_card *card,
 		return -EFAULT;
 	offset = list.offset;
 	space = list.space;
-	/* try limit maximum space */
-	if (space > 16384)
-		return -ENOMEM;
+
 	down_read(&card->controls_rwsem);
 	list.count = card->controls_count;
 	list.used = 0;
-- 
2.11.0



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