[ALSA] Fix / clean up PCM-OSS setup hooks

- Fix possible race of referring the setup hook from the running PCM
- Fix memory leak in an error path of proc write
- Clean up the setup hook parser

Signed-off-by: Takashi Iwai <tiwai@suse.de>

2 files changed, 64 insertions, 71 deletions

diff --git a/include/sound/pcm_oss.h b/include/sound/pcm_oss.h
index 1d522aaa66df..39df2baca18a 100644
--- a/include/sound/pcm_oss.h
+++ b/include/sound/pcm_oss.h
@@ -69,7 +69,7 @@ struct snd_pcm_oss_file {
 
 struct snd_pcm_oss_substream {
         unsigned oss: 1;                        /* oss mode */
-        struct snd_pcm_oss_setup *setup;                /* active setup */
+        struct snd_pcm_oss_setup setup;         /* active setup */
 };
 
 struct snd_pcm_oss_stream {
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index c056cbfe5519..91114c7aeff5 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -208,9 +208,8 @@ static int snd_pcm_oss_period_size(struct snd_pcm_substream *substream,
                         oss_buffer_size = runtime->oss.mmap_bytes;
         }
 
-        if (substream->oss.setup &&
-            substream->oss.setup->period_size > 16)
-                oss_period_size = substream->oss.setup->period_size;
+        if (substream->oss.setup.period_size > 16)
+                oss_period_size = substream->oss.setup.period_size;
         else if (runtime->oss.fragshift) {
                 oss_period_size = 1 << runtime->oss.fragshift;
                 if (oss_period_size > oss_buffer_size / 2)
@@ -252,10 +251,8 @@ static int snd_pcm_oss_period_size(struct snd_pcm_substream *substream,
 
         oss_periods = oss_buffer_size / oss_period_size;
 
-        if (substream->oss.setup) {
-                if (substream->oss.setup->periods > 1)
-                        oss_periods = substream->oss.setup->periods;
-        }
+        if (substream->oss.setup.periods > 1)
+                oss_periods = substream->oss.setup.periods;
 
         s = snd_pcm_hw_param_value_max(slave_params, SNDRV_PCM_HW_PARAM_PERIODS, NULL);
         if (runtime->oss.maxfrags && s > runtime->oss.maxfrags)
@@ -341,12 +338,10 @@ static int snd_pcm_oss_change_params(struct snd_pcm_substream *substream)
                 goto failure;
         }
 
-        if (atomic_read(&runtime->mmap_count)) {
+        if (atomic_read(&runtime->mmap_count))
                 direct = 1;
-        } else {
-                struct snd_pcm_oss_setup *setup = substream->oss.setup;
-                direct = (setup != NULL && setup->direct);
-        }
+        else
+                direct = substream->oss.setup.direct;
 
         _snd_pcm_hw_params_any(sparams);
         _snd_pcm_hw_param_setinteger(sparams, SNDRV_PCM_HW_PARAM_PERIODS);
@@ -482,7 +477,7 @@ static int snd_pcm_oss_change_params(struct snd_pcm_substream *substream)
                 1 : runtime->period_size;
         sw_params->xfer_align = 1;
         if (atomic_read(&runtime->mmap_count) ||
-            (substream->oss.setup && substream->oss.setup->nosilence)) {
+            substream->oss.setup.nosilence) {
                 sw_params->silence_threshold = 0;
                 sw_params->silence_size = 0;
         } else {
@@ -843,7 +838,7 @@ static ssize_t snd_pcm_oss_write1(struct snd_pcm_substream *substream, const cha
                         buf += tmp;
                         bytes -= tmp;
                         xfer += tmp;
-                        if ((substream->oss.setup != NULL && substream->oss.setup->partialfrag) ||
+                        if (substream->oss.setup.partialfrag ||
                             runtime->oss.buffer_used == runtime->oss.period_bytes) {
                                 tmp = snd_pcm_oss_write2(substream, runtime->oss.buffer + runtime->oss.period_ptr, 
                                                          runtime->oss.buffer_used - runtime->oss.period_ptr, 1);
@@ -1214,12 +1209,10 @@ static int snd_pcm_oss_get_formats(struct snd_pcm_oss_file *pcm_oss_file)
 
         if ((err = snd_pcm_oss_get_active_substream(pcm_oss_file, &substream)) < 0)
                 return err;
-        if (atomic_read(&substream->runtime->mmap_count)) {
+        if (atomic_read(&substream->runtime->mmap_count))
                 direct = 1;
-        } else {
-                struct snd_pcm_oss_setup *setup = substream->oss.setup;
-                direct = (setup != NULL && setup->direct);
-        }
+        else
+                direct = substream->oss.setup.direct;
         if (!direct)
                 return AFMT_MU_LAW | AFMT_U8 |
                        AFMT_S16_LE | AFMT_S16_BE |
@@ -1555,8 +1548,7 @@ static int snd_pcm_oss_get_ptr(struct snd_pcm_oss_file *pcm_oss_file, int stream
         } else {
                 delay = snd_pcm_oss_bytes(substream, delay);
                 if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
-                        struct snd_pcm_oss_setup *setup = substream->oss.setup;
-                        if (setup && setup->buggyptr)
+                        if (substream->oss.setup.buggyptr)
                                 info.blocks = (runtime->oss.buffer_bytes - delay - fixup) / runtime->oss.period_bytes;
                         else
                                 info.blocks = (delay + fixup) / runtime->oss.period_bytes;
@@ -1638,37 +1630,34 @@ static int snd_pcm_oss_get_mapbuf(struct snd_pcm_oss_file *pcm_oss_file, int str
         return -EINVAL;
 }
 
-static struct snd_pcm_oss_setup *snd_pcm_oss_look_for_setup(struct snd_pcm *pcm, int stream, const char *task_name)
+static const char *strip_task_path(const char *path)
 {
-        const char *ptr, *ptrl;
-        struct snd_pcm_oss_setup *setup;
-
-        mutex_lock(&pcm->streams[stream].oss.setup_mutex);
-        for (setup = pcm->streams[stream].oss.setup_list; setup; setup = setup->next) {
-                if (!strcmp(setup->task_name, task_name)) {
-                        mutex_unlock(&pcm->streams[stream].oss.setup_mutex);
-                        return setup;
-                }
-        }
-        ptr = ptrl = task_name;
-        while (*ptr) {
+        const char *ptr, *ptrl = NULL;
+        for (ptr = path; *ptr; ptr++) {
                 if (*ptr == '/')
                         ptrl = ptr + 1;
-                ptr++;
-        }
-        if (ptrl == task_name) {
-                goto __not_found;
-                return NULL;
         }
-        for (setup = pcm->streams[stream].oss.setup_list; setup; setup = setup->next) {
-                if (!strcmp(setup->task_name, ptrl)) {
-                        mutex_unlock(&pcm->streams[stream].oss.setup_mutex);
-                        return setup;
+        return ptrl;
+}
+
+static void snd_pcm_oss_look_for_setup(struct snd_pcm *pcm, int stream,
+                                      const char *task_name,
+                                      struct snd_pcm_oss_setup *rsetup)
+{
+        struct snd_pcm_oss_setup *setup;
+
+        mutex_lock(&pcm->streams[stream].oss.setup_mutex);
+        do {
+                for (setup = pcm->streams[stream].oss.setup_list; setup;
+                     setup = setup->next) {
+                        if (!strcmp(setup->task_name, task_name))
+                                goto out;
                 }
-        }
-      __not_found:
+        } while ((task_name = strip_task_path(task_name)) != NULL);
+ out:
+        if (setup)
+                *rsetup = *setup;
         mutex_unlock(&pcm->streams[stream].oss.setup_mutex);
-        return NULL;
 }
 
 static void snd_pcm_oss_release_substream(struct snd_pcm_substream *substream)
@@ -1690,7 +1679,7 @@ static void snd_pcm_oss_init_substream(struct snd_pcm_substream *substream,
         struct snd_pcm_runtime *runtime;
 
         substream->oss.oss = 1;
-        substream->oss.setup = setup;
+        substream->oss.setup = *setup;
         if (setup->nonblock)
                 substream->ffile->f_flags |= O_NONBLOCK;
         else
@@ -1733,7 +1722,7 @@ static int snd_pcm_oss_open_file(struct file *file,
                                  struct snd_pcm *pcm,
                                  struct snd_pcm_oss_file **rpcm_oss_file,
                                  int minor,
-                                 struct snd_pcm_oss_setup **setup)
+                                 struct snd_pcm_oss_setup *setup)
 {
         int idx, err;
         struct snd_pcm_oss_file *pcm_oss_file;
@@ -1752,7 +1741,7 @@ static int snd_pcm_oss_open_file(struct file *file,
                 f_mode = FMODE_WRITE;
 
         for (idx = 0; idx < 2; idx++) {
-                if (! setup[idx] || setup[idx]->disable)
+                if (setup[idx].disable)
                         continue;
                 if (idx == SNDRV_PCM_STREAM_PLAYBACK) {
                         if (! (f_mode & FMODE_WRITE))
@@ -1768,7 +1757,7 @@ static int snd_pcm_oss_open_file(struct file *file,
                 }
 
                 pcm_oss_file->streams[idx] = substream;
-                snd_pcm_oss_init_substream(substream, setup[idx], minor);
+                snd_pcm_oss_init_substream(substream, &setup[idx], minor);
         }
         
         if (! pcm_oss_file->streams[0] && pcm_oss_file->streams[1]) {
@@ -1799,7 +1788,7 @@ static int snd_pcm_oss_open(struct inode *inode, struct file *file)
         char task_name[32];
         struct snd_pcm *pcm;
         struct snd_pcm_oss_file *pcm_oss_file;
-        struct snd_pcm_oss_setup *setup[2];
+        struct snd_pcm_oss_setup setup[2];
         int nonblock;
         wait_queue_t wait;
 
@@ -1822,9 +1811,11 @@ static int snd_pcm_oss_open(struct inode *inode, struct file *file)
         }
         memset(setup, 0, sizeof(*setup));
         if (file->f_mode & FMODE_WRITE)
-                setup[0] = snd_pcm_oss_look_for_setup(pcm, SNDRV_PCM_STREAM_PLAYBACK, task_name);
+                snd_pcm_oss_look_for_setup(pcm, SNDRV_PCM_STREAM_PLAYBACK,
+                                           task_name, &setup[0]);
         if (file->f_mode & FMODE_READ)
-                setup[1] = snd_pcm_oss_look_for_setup(pcm, SNDRV_PCM_STREAM_CAPTURE, task_name);
+                snd_pcm_oss_look_for_setup(pcm, SNDRV_PCM_STREAM_CAPTURE,
+                                           task_name, &setup[1]);
 
         nonblock = !!(file->f_flags & O_NONBLOCK);
         if (!nonblock)
@@ -2249,13 +2240,8 @@ static void snd_pcm_oss_proc_read(struct snd_info_entry *entry,
 
 static void snd_pcm_oss_proc_free_setup_list(struct snd_pcm_str * pstr)
 {
-        unsigned int idx;
-        struct snd_pcm_substream *substream;
         struct snd_pcm_oss_setup *setup, *setupn;
 
-        for (idx = 0, substream = pstr->substream;
-             idx < pstr->substream_count; idx++, substream = substream->next)
-                substream->oss.setup = NULL;
         for (setup = pstr->oss.setup_list, pstr->oss.setup_list = NULL;
              setup; setup = setupn) {
                 setupn = setup->next;
@@ -2316,21 +2302,28 @@ static void snd_pcm_oss_proc_write(struct snd_info_entry *entry,
                         }
                 } while (*str);
                 if (setup == NULL) {
-                        setup = kmalloc(sizeof(struct snd_pcm_oss_setup), GFP_KERNEL);
-                        if (setup) {
-                                if (pstr->oss.setup_list == NULL) {
-                                        pstr->oss.setup_list = setup;
-                                } else {
-                                        for (setup1 = pstr->oss.setup_list; setup1->next; setup1 = setup1->next);
-                                        setup1->next = setup;
-                                }
-                                template.task_name = kstrdup(task_name, GFP_KERNEL);
-                        } else {
+                        setup = kmalloc(sizeof(*setup), GFP_KERNEL);
+                        if (! setup) {
+                                buffer->error = -ENOMEM;
+                                mutex_lock(&pstr->oss.setup_mutex);
+                                return;
+                        }
+                        if (pstr->oss.setup_list == NULL)
+                                pstr->oss.setup_list = setup;
+                        else {
+                                for (setup1 = pstr->oss.setup_list;
+                                     setup1->next; setup1 = setup1->next);
+                                setup1->next = setup;
+                        }
+                        template.task_name = kstrdup(task_name, GFP_KERNEL);
+                        if (! template.task_name) {
+                                kfree(setup);
                                 buffer->error = -ENOMEM;
+                                mutex_lock(&pstr->oss.setup_mutex);
+                                return;
                         }
                 }
-                if (setup)
-                        *setup = template;
+                *setup = template;
                 mutex_unlock(&pstr->oss.setup_mutex);
         }
 }