Hi,
On May 23 2017 00:52, Takashi Iwai wrote:
This patch simplifies the code of snd_ctl_elem_list() in the following ways:
Avoid a vmalloc() temporary buffer but do copy in each iteration; the vmalloc buffer was introduced at the time we took the spinlock for the ctl element management.
Use the standard list_for_each_entry() macro
Merge two loops into one; it used to be a loop for skipping until offset becomes zero and another loop to copy the data. They can be folded into a single loop easily.
Signed-off-by: Takashi Iwai tiwai@suse.de
Reviewed-by: Takashi Sakamoto o-takashi@sakamocchi.jp Tested-by: Takashi Sakamoto o-takashi@sakamocchi.jp
I have one comment.
sound/core/control.c | 66 +++++++++++++++++++--------------------------------- 1 file changed, 24 insertions(+), 42 deletions(-)
diff --git a/sound/core/control.c b/sound/core/control.c index c109b82eef4b..47080da8451a 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -747,11 +747,11 @@ static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl, static int snd_ctl_elem_list(struct snd_card *card, struct snd_ctl_elem_list __user *_list) {
- struct list_head *plist; struct snd_ctl_elem_list list; struct snd_kcontrol *kctl;
- struct snd_ctl_elem_id *dst, *id;
struct snd_ctl_elem_id id; unsigned int offset, space, jidx;
int err = 0;
if (copy_from_user(&list, _list, sizeof(list))) return -EFAULT;
@@ -760,52 +760,34 @@ static int snd_ctl_elem_list(struct snd_card *card, /* try limit maximum space */ if (space > 16384) return -ENOMEM;
We can get rid of this limitation because allocation in kernel space is not performed anymore.
Regards
Takashi Sakamoto