[alsa-devel] [PATCH 13/15] ALSA: hda - Fix concurrent hash accesses
Takashi Iwai
tiwai at suse.de
Mon May 14 17:32:04 CEST 2012
The amp and caps hashes aren't protected properly for concurrent
accesses. Protect them via a new mutex now.
But it can't be so simple as originally thought: since the update of a
hash table entry itself might trigger the power-up sequence which
again accesses the hash table, we can't cover the whole function
simply via mutex. Thus the update part has to be split from the mutex
and revalidated.
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
sound/pci/hda/hda_codec.c | 201 +++++++++++++++++++++++++++------------------
sound/pci/hda/hda_codec.h | 1 +
2 files changed, 121 insertions(+), 81 deletions(-)
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 5e7c4bf..7a621f5 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -1255,6 +1255,7 @@ int /*__devinit*/ snd_hda_codec_new(struct hda_bus *bus,
codec->addr = codec_addr;
mutex_init(&codec->spdif_mutex);
mutex_init(&codec->control_mutex);
+ mutex_init(&codec->hash_mutex);
init_hda_cache(&codec->amp_cache, sizeof(struct hda_amp_info));
init_hda_cache(&codec->cmd_cache, sizeof(struct hda_cache_head));
snd_array_init(&codec->mixers, sizeof(struct hda_nid_item), 32);
@@ -1605,6 +1606,60 @@ get_alloc_amp_hash(struct hda_codec *codec, u32 key)
return (struct hda_amp_info *)get_alloc_hash(&codec->amp_cache, key);
}
+/* overwrite the value with the key in the caps hash */
+static int write_caps_hash(struct hda_codec *codec, u32 key, unsigned int val)
+{
+ struct hda_amp_info *info;
+
+ mutex_lock(&codec->hash_mutex);
+ info = get_alloc_amp_hash(codec, key);
+ if (!info) {
+ mutex_unlock(&codec->hash_mutex);
+ return -EINVAL;
+ }
+ info->amp_caps = val;
+ info->head.val |= INFO_AMP_CAPS;
+ mutex_unlock(&codec->hash_mutex);
+ return 0;
+}
+
+/* query the value from the caps hash; if not found, fetch the current
+ * value from the given function and store in the hash
+ */
+static unsigned int
+query_caps_hash(struct hda_codec *codec, hda_nid_t nid, int dir, u32 key,
+ unsigned int (*func)(struct hda_codec *, hda_nid_t, int))
+{
+ struct hda_amp_info *info;
+ unsigned int val;
+
+ mutex_lock(&codec->hash_mutex);
+ info = get_alloc_amp_hash(codec, key);
+ if (!info) {
+ mutex_unlock(&codec->hash_mutex);
+ return 0;
+ }
+ if (!(info->head.val & INFO_AMP_CAPS)) {
+ mutex_unlock(&codec->hash_mutex); /* for reentrance */
+ val = func(codec, nid, dir);
+ write_caps_hash(codec, key, val);
+ } else {
+ val = info->amp_caps;
+ mutex_unlock(&codec->hash_mutex);
+ }
+ return val;
+}
+
+static unsigned int read_amp_cap(struct hda_codec *codec, hda_nid_t nid,
+ int direction)
+{
+ if (!(get_wcaps(codec, nid) & AC_WCAP_AMP_OVRD))
+ nid = codec->afg;
+ return snd_hda_param_read(codec, nid,
+ direction == HDA_OUTPUT ?
+ AC_PAR_AMP_OUT_CAP : AC_PAR_AMP_IN_CAP);
+}
+
/**
* query_amp_caps - query AMP capabilities
* @codec: the HD-auio codec
@@ -1619,22 +1674,9 @@ get_alloc_amp_hash(struct hda_codec *codec, u32 key)
*/
u32 query_amp_caps(struct hda_codec *codec, hda_nid_t nid, int direction)
{
- struct hda_amp_info *info;
-
- info = get_alloc_amp_hash(codec, HDA_HASH_KEY(nid, direction, 0));
- if (!info)
- return 0;
- if (!(info->head.val & INFO_AMP_CAPS)) {
- if (!(get_wcaps(codec, nid) & AC_WCAP_AMP_OVRD))
- nid = codec->afg;
- info->amp_caps = snd_hda_param_read(codec, nid,
- direction == HDA_OUTPUT ?
- AC_PAR_AMP_OUT_CAP :
- AC_PAR_AMP_IN_CAP);
- if (info->amp_caps)
- info->head.val |= INFO_AMP_CAPS;
- }
- return info->amp_caps;
+ return query_caps_hash(codec, nid, direction,
+ HDA_HASH_KEY(nid, direction, 0),
+ read_amp_cap);
}
EXPORT_SYMBOL_HDA(query_amp_caps);
@@ -1654,34 +1696,12 @@ EXPORT_SYMBOL_HDA(query_amp_caps);
int snd_hda_override_amp_caps(struct hda_codec *codec, hda_nid_t nid, int dir,
unsigned int caps)
{
- struct hda_amp_info *info;
-
- info = get_alloc_amp_hash(codec, HDA_HASH_KEY(nid, dir, 0));
- if (!info)
- return -EINVAL;
- info->amp_caps = caps;
- info->head.val |= INFO_AMP_CAPS;
- return 0;
+ return write_caps_hash(codec, HDA_HASH_KEY(nid, dir, 0), caps);
}
EXPORT_SYMBOL_HDA(snd_hda_override_amp_caps);
-static unsigned int
-query_caps_hash(struct hda_codec *codec, hda_nid_t nid, u32 key,
- unsigned int (*func)(struct hda_codec *, hda_nid_t))
-{
- struct hda_amp_info *info;
-
- info = get_alloc_amp_hash(codec, key);
- if (!info)
- return 0;
- if (!info->head.val) {
- info->head.val |= INFO_AMP_CAPS;
- info->amp_caps = func(codec, nid);
- }
- return info->amp_caps;
-}
-
-static unsigned int read_pin_cap(struct hda_codec *codec, hda_nid_t nid)
+static unsigned int read_pin_cap(struct hda_codec *codec, hda_nid_t nid,
+ int dir)
{
return snd_hda_param_read(codec, nid, AC_PAR_PIN_CAP);
}
@@ -1699,7 +1719,7 @@ static unsigned int read_pin_cap(struct hda_codec *codec, hda_nid_t nid)
*/
u32 snd_hda_query_pin_caps(struct hda_codec *codec, hda_nid_t nid)
{
- return query_caps_hash(codec, nid, HDA_HASH_PINCAP_KEY(nid),
+ return query_caps_hash(codec, nid, 0, HDA_HASH_PINCAP_KEY(nid),
read_pin_cap);
}
EXPORT_SYMBOL_HDA(snd_hda_query_pin_caps);
@@ -1717,41 +1737,47 @@ EXPORT_SYMBOL_HDA(snd_hda_query_pin_caps);
int snd_hda_override_pin_caps(struct hda_codec *codec, hda_nid_t nid,
unsigned int caps)
{
- struct hda_amp_info *info;
- info = get_alloc_amp_hash(codec, HDA_HASH_PINCAP_KEY(nid));
- if (!info)
- return -ENOMEM;
- info->amp_caps = caps;
- info->head.val |= INFO_AMP_CAPS;
- return 0;
+ return write_caps_hash(codec, HDA_HASH_PINCAP_KEY(nid), caps);
}
EXPORT_SYMBOL_HDA(snd_hda_override_pin_caps);
-/*
- * read the current volume to info
- * if the cache exists, read the cache value.
+/* read or sync the hash value with the current value;
+ * call within hash_mutex
*/
-static unsigned int get_vol_mute(struct hda_codec *codec,
- struct hda_amp_info *info, hda_nid_t nid,
- int ch, int direction, int index)
+static struct hda_amp_info *
+update_amp_hash(struct hda_codec *codec, hda_nid_t nid, int ch,
+ int direction, int index)
{
- u32 val, parm;
-
- if (info->head.val & INFO_AMP_VOL(ch))
- return info->vol[ch];
+ struct hda_amp_info *info;
+ unsigned int parm, val = 0;
+ bool val_read = false;
- parm = ch ? AC_AMP_GET_RIGHT : AC_AMP_GET_LEFT;
- parm |= direction == HDA_OUTPUT ? AC_AMP_GET_OUTPUT : AC_AMP_GET_INPUT;
- parm |= index;
- val = snd_hda_codec_read(codec, nid, 0,
+ retry:
+ info = get_alloc_amp_hash(codec, HDA_HASH_KEY(nid, direction, index));
+ if (!info)
+ return NULL;
+ if (!(info->head.val & INFO_AMP_VOL(ch))) {
+ if (!val_read) {
+ mutex_unlock(&codec->hash_mutex);
+ parm = ch ? AC_AMP_GET_RIGHT : AC_AMP_GET_LEFT;
+ parm |= direction == HDA_OUTPUT ?
+ AC_AMP_GET_OUTPUT : AC_AMP_GET_INPUT;
+ parm |= index;
+ val = snd_hda_codec_read(codec, nid, 0,
AC_VERB_GET_AMP_GAIN_MUTE, parm);
- info->vol[ch] = val & 0xff;
- info->head.val |= INFO_AMP_VOL(ch);
- return info->vol[ch];
+ val &= 0xff;
+ val_read = true;
+ mutex_lock(&codec->hash_mutex);
+ goto retry;
+ }
+ info->vol[ch] = val;
+ info->head.val |= INFO_AMP_VOL(ch);
+ }
+ return info;
}
/*
- * write the current volume in info to the h/w and update the cache
+ * write the current volume in info to the h/w
*/
static void put_vol_mute(struct hda_codec *codec, struct hda_amp_info *info,
hda_nid_t nid, int ch, int direction, int index,
@@ -1768,7 +1794,6 @@ static void put_vol_mute(struct hda_codec *codec, struct hda_amp_info *info,
else
parm |= val;
snd_hda_codec_write(codec, nid, 0, AC_VERB_SET_AMP_GAIN_MUTE, parm);
- info->vol[ch] = val;
}
/**
@@ -1785,10 +1810,14 @@ int snd_hda_codec_amp_read(struct hda_codec *codec, hda_nid_t nid, int ch,
int direction, int index)
{
struct hda_amp_info *info;
- info = get_alloc_amp_hash(codec, HDA_HASH_KEY(nid, direction, index));
- if (!info)
- return 0;
- return get_vol_mute(codec, info, nid, ch, direction, index);
+ unsigned int val = 0;
+
+ mutex_lock(&codec->hash_mutex);
+ info = update_amp_hash(codec, nid, ch, direction, index);
+ if (info)
+ val = info->vol[ch];
+ mutex_unlock(&codec->hash_mutex);
+ return val;
}
EXPORT_SYMBOL_HDA(snd_hda_codec_amp_read);
@@ -1810,15 +1839,23 @@ int snd_hda_codec_amp_update(struct hda_codec *codec, hda_nid_t nid, int ch,
{
struct hda_amp_info *info;
- info = get_alloc_amp_hash(codec, HDA_HASH_KEY(nid, direction, idx));
- if (!info)
- return 0;
if (snd_BUG_ON(mask & ~0xff))
mask &= 0xff;
val &= mask;
- val |= get_vol_mute(codec, info, nid, ch, direction, idx) & ~mask;
- if (info->vol[ch] == val)
+
+ mutex_lock(&codec->hash_mutex);
+ info = update_amp_hash(codec, nid, ch, direction, idx);
+ if (!info) {
+ mutex_unlock(&codec->hash_mutex);
+ return 0;
+ }
+ val |= info->vol[ch] & ~mask;
+ if (info->vol[ch] == val) {
+ mutex_unlock(&codec->hash_mutex);
return 0;
+ }
+ info->vol[ch] = val;
+ mutex_unlock(&codec->hash_mutex);
put_vol_mute(codec, info, nid, ch, direction, idx, val);
return 1;
}
@@ -3693,7 +3730,8 @@ unsigned int snd_hda_calc_stream_format(unsigned int rate,
}
EXPORT_SYMBOL_HDA(snd_hda_calc_stream_format);
-static unsigned int get_pcm_param(struct hda_codec *codec, hda_nid_t nid)
+static unsigned int get_pcm_param(struct hda_codec *codec, hda_nid_t nid,
+ int dir)
{
unsigned int val = 0;
if (nid != codec->afg &&
@@ -3708,11 +3746,12 @@ static unsigned int get_pcm_param(struct hda_codec *codec, hda_nid_t nid)
static unsigned int query_pcm_param(struct hda_codec *codec, hda_nid_t nid)
{
- return query_caps_hash(codec, nid, HDA_HASH_PARPCM_KEY(nid),
+ return query_caps_hash(codec, nid, 0, HDA_HASH_PARPCM_KEY(nid),
get_pcm_param);
}
-static unsigned int get_stream_param(struct hda_codec *codec, hda_nid_t nid)
+static unsigned int get_stream_param(struct hda_codec *codec, hda_nid_t nid,
+ int dir)
{
unsigned int streams = snd_hda_param_read(codec, nid, AC_PAR_STREAM);
if (!streams || streams == -1)
@@ -3724,7 +3763,7 @@ static unsigned int get_stream_param(struct hda_codec *codec, hda_nid_t nid)
static unsigned int query_stream_param(struct hda_codec *codec, hda_nid_t nid)
{
- return query_caps_hash(codec, nid, HDA_HASH_PARSTR_KEY(nid),
+ return query_caps_hash(codec, nid, 0, HDA_HASH_PARSTR_KEY(nid),
get_stream_param);
}
diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
index fce30b4..29a311b 100644
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -827,6 +827,7 @@ struct hda_codec {
struct mutex spdif_mutex;
struct mutex control_mutex;
+ struct mutex hash_mutex;
struct snd_array spdif_out;
unsigned int spdif_in_enable; /* SPDIF input enable? */
const hda_nid_t *slave_dig_outs; /* optional digital out slave widgets */
--
1.7.9.2
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