[ALSA] Add O_APPEND flag support to PCM

Added O_APPEND flag support to PCM to enable shared substreams
among multiple processes.  This mechanism is used by dmix and
dsnoop plugins.

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

1 files changed, 10 insertions, 7 deletions

diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index d8b7416ee00..9803a6ce3d4 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -1331,7 +1331,7 @@ static ssize_t snd_pcm_oss_write1(struct snd_pcm_substream *substream, const cha
                                 if (runtime->oss.period_ptr == 0 ||
                                     runtime->oss.period_ptr == runtime->oss.buffer_used)
                                         runtime->oss.buffer_used = 0;
-                                else if ((substream->ffile->f_flags & O_NONBLOCK) != 0)
+                                else if ((substream->f_flags & O_NONBLOCK) != 0)
                                         return xfer > 0 ? xfer : -EAGAIN;
                         }
                 } else {
@@ -1344,7 +1344,7 @@ static ssize_t snd_pcm_oss_write1(struct snd_pcm_substream *substream, const cha
                         buf += tmp;
                         bytes -= tmp;
                         xfer += tmp;
-                        if ((substream->ffile->f_flags & O_NONBLOCK) != 0 &&
+                        if ((substream->f_flags & O_NONBLOCK) != 0 &&
                             tmp != runtime->oss.period_bytes)
                                 break;
                 }
@@ -1582,10 +1582,10 @@ static int snd_pcm_oss_sync(struct snd_pcm_oss_file *pcm_oss_file)
                  * finish sync: drain the buffer
                  */
               __direct:
-                saved_f_flags = substream->ffile->f_flags;
-                substream->ffile->f_flags &= ~O_NONBLOCK;
+                saved_f_flags = substream->f_flags;
+                substream->f_flags &= ~O_NONBLOCK;
                 err = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DRAIN, NULL);
-                substream->ffile->f_flags = saved_f_flags;
+                substream->f_flags = saved_f_flags;
                 if (err < 0)
                         return err;
                 runtime->oss.prepare = 1;
@@ -2164,9 +2164,9 @@ static void snd_pcm_oss_init_substream(struct snd_pcm_substream *substream,
         substream->oss.oss = 1;
         substream->oss.setup = *setup;
         if (setup->nonblock)
-                substream->ffile->f_flags |= O_NONBLOCK;
+                substream->f_flags |= O_NONBLOCK;
         else if (setup->block)
-                substream->ffile->f_flags &= ~O_NONBLOCK;
+                substream->f_flags &= ~O_NONBLOCK;
         runtime = substream->runtime;
         runtime->oss.params = 1;
         runtime->oss.trigger = 1;
@@ -2223,6 +2223,7 @@ static int snd_pcm_oss_open_file(struct file *file,
             (pcm->info_flags & SNDRV_PCM_INFO_HALF_DUPLEX))
                 f_mode = FMODE_WRITE;
 
+        file->f_flags &= ~O_APPEND;
         for (idx = 0; idx < 2; idx++) {
                 if (setup[idx].disable)
                         continue;
@@ -2540,6 +2541,7 @@ static ssize_t snd_pcm_oss_read(struct file *file, char __user *buf, size_t coun
         substream = pcm_oss_file->streams[SNDRV_PCM_STREAM_CAPTURE];
         if (substream == NULL)
                 return -ENXIO;
+        substream->f_flags = file->f_flags & O_NONBLOCK;
 #ifndef OSS_DEBUG
         return snd_pcm_oss_read1(substream, buf, count);
 #else
@@ -2561,6 +2563,7 @@ static ssize_t snd_pcm_oss_write(struct file *file, const char __user *buf, size
         substream = pcm_oss_file->streams[SNDRV_PCM_STREAM_PLAYBACK];
         if (substream == NULL)
                 return -ENXIO;
+        substream->f_flags = file->f_flags & O_NONBLOCK;
         result = snd_pcm_oss_write1(substream, buf, count);
 #ifdef OSS_DEBUG
         printk("pcm_oss: write %li bytes (wrote %li bytes)\n", (long)count, (long)result);