ALSA: pcm: Add missing error checks in OSS emulation plugin builder

In the OSS emulation plugin builder where the frame size is parsed in
the plugin chain, some places miss the possible errors returned from
the plugin src_ or dst_frames callback.

This patch papers over such places.

Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/oss/pcm_plugin.c b/sound/core/oss/pcm_plugin.c
index cadc937928683cb3abcf7ec8208e8159df31c00f..85a56af104bd619160ace33f51ad2786eca3279a 100644 (file)
--- a/sound/core/oss/pcm_plugin.c
+++ b/sound/core/oss/pcm_plugin.c
@@ -592,18 +592,26 @@ snd_pcm_sframes_t snd_pcm_plug_write_transfer(struct snd_pcm_substream *plug, st
        snd_pcm_sframes_t frames = size;
 
        plugin = snd_pcm_plug_first(plug);
-       while (plugin && frames > 0) {
+       while (plugin) {
+               if (frames <= 0)
+                       return frames;
                if ((next = plugin->next) != NULL) {
                        snd_pcm_sframes_t frames1 = frames;
-                       if (plugin->dst_frames)
+                       if (plugin->dst_frames) {
                                frames1 = plugin->dst_frames(plugin, frames);
+                               if (frames1 <= 0)
+                                       return frames1;
+                       }
                        if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
                                return err;
                        }
                        if (err != frames1) {
                                frames = err;
-                               if (plugin->src_frames)
+                               if (plugin->src_frames) {
                                        frames = plugin->src_frames(plugin, frames1);
+                                       if (frames <= 0)
+                                               return frames;
+                               }
                        }
                } else
                        dst_channels = NULL;