ALSA: pcm: Allow aborting mutex lock at OSS read/write loops

[pandora-kernel.git] / sound / core / oss / pcm_oss.c

diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index 3cc4b86..15ae278 100644 (file)
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -465,7 +465,6 @@ static int snd_pcm_hw_param_near(struct snd_pcm_substream *pcm,
                v = snd_pcm_hw_param_last(pcm, params, var, dir);
        else
                v = snd_pcm_hw_param_first(pcm, params, var, dir);
-       snd_BUG_ON(v < 0);
        return v;
 }
 
@@ -834,7 +833,8 @@ static int choose_rate(struct snd_pcm_substream *substream,
        return snd_pcm_hw_param_near(substream, params, SNDRV_PCM_HW_PARAM_RATE, best_rate, NULL);
 }
 
-static int snd_pcm_oss_change_params(struct snd_pcm_substream *substream)
+static int snd_pcm_oss_change_params(struct snd_pcm_substream *substream,
+                                    bool trylock)
 {
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_pcm_hw_params *params, *sparams;
@@ -848,7 +848,10 @@ static int snd_pcm_oss_change_params(struct snd_pcm_substream *substream)
        struct snd_mask sformat_mask;
        struct snd_mask mask;
 
-       if (mutex_lock_interruptible(&runtime->oss.params_lock))
+       if (trylock) {
+               if (!(mutex_trylock(&runtime->oss.params_lock)))
+                       return -EAGAIN;
+       } else if (mutex_lock_interruptible(&runtime->oss.params_lock))
                return -EINTR;
        sw_params = kmalloc(sizeof(*sw_params), GFP_KERNEL);
        params = kmalloc(sizeof(*params), GFP_KERNEL);
@@ -1091,7 +1094,7 @@ static int snd_pcm_oss_get_active_substream(struct snd_pcm_oss_file *pcm_oss_fil
                if (asubstream == NULL)
                        asubstream = substream;
                if (substream->runtime->oss.params) {
-                       err = snd_pcm_oss_change_params(substream);
+                       err = snd_pcm_oss_change_params(substream, false);
                        if (err < 0)
                                return err;
                }
@@ -1130,7 +1133,7 @@ static int snd_pcm_oss_make_ready(struct snd_pcm_substream *substream)
                return 0;
        runtime = substream->runtime;
        if (runtime->oss.params) {
-               err = snd_pcm_oss_change_params(substream);
+               err = snd_pcm_oss_change_params(substream, false);
                if (err < 0)
                        return err;
        }
@@ -1372,8 +1375,11 @@ static ssize_t snd_pcm_oss_write1(struct snd_pcm_substream *substream, const cha
 
        if ((tmp = snd_pcm_oss_make_ready(substream)) < 0)
                return tmp;
-       mutex_lock(&runtime->oss.params_lock);
        while (bytes > 0) {
+               if (mutex_lock_interruptible(&runtime->oss.params_lock)) {
+                       tmp = -ERESTARTSYS;
+                       break;
+               }
                if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) {
                        tmp = bytes;
                        if (tmp + runtime->oss.buffer_used > runtime->oss.period_bytes)
@@ -1417,14 +1423,18 @@ static ssize_t snd_pcm_oss_write1(struct snd_pcm_substream *substream, const cha
                        xfer += tmp;
                        if ((substream->f_flags & O_NONBLOCK) != 0 &&
                            tmp != runtime->oss.period_bytes)
-                               break;
+                               tmp = -EAGAIN;
                }
-       }
-       mutex_unlock(&runtime->oss.params_lock);
-       return xfer;
-
  err:
-       mutex_unlock(&runtime->oss.params_lock);
+               mutex_unlock(&runtime->oss.params_lock);
+               if (tmp < 0)
+                       break;
+               if (signal_pending(current)) {
+                       tmp = -ERESTARTSYS;
+                       break;
+               }
+               tmp = 0;
+       }
        return xfer > 0 ? (snd_pcm_sframes_t)xfer : tmp;
 }
 
@@ -1472,8 +1482,11 @@ static ssize_t snd_pcm_oss_read1(struct snd_pcm_substream *substream, char __use
 
        if ((tmp = snd_pcm_oss_make_ready(substream)) < 0)
                return tmp;
-       mutex_lock(&runtime->oss.params_lock);
        while (bytes > 0) {
+               if (mutex_lock_interruptible(&runtime->oss.params_lock)) {
+                       tmp = -ERESTARTSYS;
+                       break;
+               }
                if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) {
                        if (runtime->oss.buffer_used == 0) {
                                tmp = snd_pcm_oss_read2(substream, runtime->oss.buffer, runtime->oss.period_bytes, 1);
@@ -1504,12 +1517,16 @@ static ssize_t snd_pcm_oss_read1(struct snd_pcm_substream *substream, char __use
                        bytes -= tmp;
                        xfer += tmp;
                }
-       }
-       mutex_unlock(&runtime->oss.params_lock);
-       return xfer;
-
  err:
-       mutex_unlock(&runtime->oss.params_lock);
+               mutex_unlock(&runtime->oss.params_lock);
+               if (tmp < 0)
+                       break;
+               if (signal_pending(current)) {
+                       tmp = -ERESTARTSYS;
+                       break;
+               }
+               tmp = 0;
+       }
        return xfer > 0 ? (snd_pcm_sframes_t)xfer : tmp;
 }
 
@@ -2168,7 +2185,7 @@ static int snd_pcm_oss_get_space(struct snd_pcm_oss_file *pcm_oss_file, int stre
        runtime = substream->runtime;
 
        if (runtime->oss.params &&
-           (err = snd_pcm_oss_change_params(substream)) < 0)
+           (err = snd_pcm_oss_change_params(substream, false)) < 0)
                return err;
 
        info.fragsize = runtime->oss.period_bytes;
@@ -2441,6 +2458,10 @@ static int snd_pcm_oss_open(struct inode *inode, struct file *file)
                mutex_unlock(&pcm->open_mutex);
                schedule();
                mutex_lock(&pcm->open_mutex);
+               if (pcm->card->shutdown) {
+                       err = -ENODEV;
+                       break;
+               }
                if (signal_pending(current)) {
                        err = -ERESTARTSYS;
                        break;
@@ -2450,6 +2471,7 @@ static int snd_pcm_oss_open(struct inode *inode, struct file *file)
        mutex_unlock(&pcm->open_mutex);
        if (err < 0)
                goto __error;
+       snd_card_unref(pcm->card);
        return err;
 
       __error:
@@ -2457,6 +2479,8 @@ static int snd_pcm_oss_open(struct inode *inode, struct file *file)
       __error2:
        snd_card_file_remove(pcm->card, file);
       __error1:
+       if (pcm)
+               snd_card_unref(pcm->card);
        return err;
 }
 
@@ -2797,7 +2821,12 @@ static int snd_pcm_oss_mmap(struct file *file, struct vm_area_struct *area)
                return -EIO;
        
        if (runtime->oss.params) {
-               if ((err = snd_pcm_oss_change_params(substream)) < 0)
+               /* use mutex_trylock() for params_lock for avoiding a deadlock
+                * between mmap_sem and params_lock taken by
+                * copy_from/to_user() in snd_pcm_oss_write/read()
+                */
+               err = snd_pcm_oss_change_params(substream, true);
+               if (err < 0)
                        return err;
        }
 #ifdef CONFIG_SND_PCM_OSS_PLUGINS