[ALSA] Fix control/status mmap with shared PCM substream

The flag to avoid 32bit-incompatible mmap for control/status records
should be outside the pcm substream instance since a substream can be
shared among multiple opens.  Now it's flagged in pcm_file list that
is directly assigned to file->private_data.
Also, removed snd_pcm_add_file() and remove_file() functions and
substream.files field that are not really used in the code.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

2 files changed, 11 insertions, 40 deletions

diff --git a/sound/core/pcm_compat.c b/sound/core/pcm_compat.c
index 2b8aab6fd6cd..2b539799d23b 100644
--- a/sound/core/pcm_compat.c
+++ b/sound/core/pcm_compat.c
@@ -478,7 +478,7 @@ static long snd_pcm_ioctl_compat(struct file *file, unsigned int cmd, unsigned l
          * mmap of PCM status/control records because of the size
          * incompatibility.
          */
-        substream->no_mmap_ctrl = 1;
+        pcm_file->no_compat_mmap = 1;
 
         switch (cmd) {
         case SNDRV_PCM_IOCTL_PVERSION:
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 439f047929e1..0224c70414f5 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -1992,35 +1992,9 @@ int snd_pcm_hw_constraints_complete(struct snd_pcm_substream *substream)
         return 0;
 }
 
-static void snd_pcm_add_file(struct snd_pcm_str *str,
-                             struct snd_pcm_file *pcm_file)
-{
-        pcm_file->next = str->files;
-        str->files = pcm_file;
-}
-
-static void snd_pcm_remove_file(struct snd_pcm_str *str,
-                                struct snd_pcm_file *pcm_file)
-{
-        struct snd_pcm_file * pcm_file1;
-        if (str->files == pcm_file) {
-                str->files = pcm_file->next;
-        } else {
-                pcm_file1 = str->files;
-                while (pcm_file1 && pcm_file1->next != pcm_file)
-                        pcm_file1 = pcm_file1->next;
-                if (pcm_file1 != NULL)
-                        pcm_file1->next = pcm_file->next;
-        }
-}
-
 static void pcm_release_private(struct snd_pcm_substream *substream)
 {
-        struct snd_pcm_file *pcm_file = substream->file;
-
         snd_pcm_unlink(substream);
-        snd_pcm_remove_file(substream->pstr, pcm_file);
-        kfree(pcm_file);
 }
 
 void snd_pcm_release_substream(struct snd_pcm_substream *substream)
@@ -2060,7 +2034,6 @@ int snd_pcm_open_substream(struct snd_pcm *pcm, int stream,
                 return 0;
         }
 
-        substream->no_mmap_ctrl = 0;
         err = snd_pcm_hw_constraints_init(substream);
         if (err < 0) {
                 snd_printd("snd_pcm_hw_constraints_init failed\n");
@@ -2105,19 +2078,16 @@ static int snd_pcm_open_file(struct file *file,
         if (err < 0)
                 return err;
 
-        if (substream->ref_count > 1)
-                pcm_file = substream->file;
-        else {
-                pcm_file = kzalloc(sizeof(*pcm_file), GFP_KERNEL);
-                if (pcm_file == NULL) {
-                        snd_pcm_release_substream(substream);
-                        return -ENOMEM;
-                }
+        pcm_file = kzalloc(sizeof(*pcm_file), GFP_KERNEL);
+        if (pcm_file == NULL) {
+                snd_pcm_release_substream(substream);
+                return -ENOMEM;
+        }
+        pcm_file->substream = substream;
+        if (substream->ref_count == 1) {
                 str = substream->pstr;
                 substream->file = pcm_file;
                 substream->pcm_release = pcm_release_private;
-                pcm_file->substream = substream;
-                snd_pcm_add_file(str, pcm_file);
         }
         file->private_data = pcm_file;
         *rpcm_file = pcm_file;
@@ -2209,6 +2179,7 @@ static int snd_pcm_release(struct inode *inode, struct file *file)
         fasync_helper(-1, file, 0, &substream->runtime->fasync);
         mutex_lock(&pcm->open_mutex);
         snd_pcm_release_substream(substream);
+        kfree(pcm_file);
         mutex_unlock(&pcm->open_mutex);
         wake_up(&pcm->open_wait);
         module_put(pcm->card->module);
@@ -3270,11 +3241,11 @@ static int snd_pcm_mmap(struct file *file, struct vm_area_struct *area)
         offset = area->vm_pgoff << PAGE_SHIFT;
         switch (offset) {
         case SNDRV_PCM_MMAP_OFFSET_STATUS:
-                if (substream->no_mmap_ctrl)
+                if (pcm_file->no_compat_mmap)
                         return -ENXIO;
                 return snd_pcm_mmap_status(substream, file, area);
         case SNDRV_PCM_MMAP_OFFSET_CONTROL:
-                if (substream->no_mmap_ctrl)
+                if (pcm_file->no_compat_mmap)
                         return -ENXIO;
                 return snd_pcm_mmap_control(substream, file, area);
         default: