mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-07-22 01:08:13 -04:00
Code Issues Packages Projects Releases Wiki Activity

ALSA: core: Use flexible array for card private data

Browse Source 
snd_card_new() and snd_devm_card_new() allocate struct snd_card
together with optional driver-private storage. The storage is currently
described only by open-coded sizeof(*card) + extra_size arithmetic, and
snd_card_init() reaches it by manually adding sizeof(struct snd_card) to
the card pointer.

Make the trailing storage explicit with a flexible array member. Use
kzalloc_flex() for the regular allocation path and struct_size() for the
devres allocation size. This documents the layout and avoids open-coded
variable-size object arithmetic.

Align the flexible array to unsigned long long so the driver-private area
does not become less aligned than the old sizeof(struct snd_card) tail
address on 32-bit ABIs.

Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260531-alsa-card-private-flex-array-v2-1-e4ff67f5bd23@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Cássio Gabriel
2026-05-31 22:23:35 -03:00
committed by Takashi Iwai
parent 8a2d0b5496
commit e9c82f767f
2 changed files with 6 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
include/sound/core.h
View File

@@ -148,6 +148,8 @@ struct snd_card {
struct snd_mixer_oss *mixer_oss;
int mixer_oss_change_count;
#endif
unsigned char private_data_area[] __aligned(__alignof__(unsigned long long));
};
#define dev_to_snd_card(p) container_of(p, struct snd_card, card_dev)

7
sound/core/init.c
View File

@@ -181,7 +181,7 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
if (extra_size < 0)
extra_size = 0;
card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
card = kzalloc_flex(*card, private_data_area, extra_size);
if (!card)
return -ENOMEM;
@@ -232,7 +232,8 @@ int snd_devm_card_new(struct device *parent, int idx, const char *xid,
int err;
*card_ret = NULL;
card = devres_alloc(__snd_card_release, sizeof(*card) + extra_size,
card = devres_alloc(__snd_card_release,
struct_size(card, private_data_area, extra_size),
GFP_KERNEL);
if (!card)
return -ENOMEM;
@@ -280,7 +281,7 @@ static int snd_card_init(struct snd_card *card, struct device *parent,
int err;
if (extra_size > 0)
card->private_data = (char *)card + sizeof(struct snd_card);
card->private_data = card->private_data_area;
if (xid)
strscpy(card->id, xid, sizeof(card->id));
err = 0;