ALSA: compress: Disable GET_CODEC_CAPS ioctl for some architectures

Some architectures like PowerPC can handle the maximum struct size in
an ioctl only up to 13 bits, and struct snd_compr_codec_caps used by
SNDRV_COMPRESS_GET_CODEC_CAPS ioctl overflows this limit.  This
problem was revealed recently by a powerpc change, as it's now treated
as a fatal build error.

This patch is a stop-gap for that: for architectures with less than 14
bit ioctl struct size, get rid of the handling of the relevant ioctl.
We should provide an alternative equivalent ioctl code later, but for
now just paper over it.  Luckily, the compress API hasn't been used on
such architectures, so the impact must be effectively zero.

Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
index 18b8dc45bb8f77ea0c2ce16e79305c7872f057bc..7fac3cae8abd0a232a3d7a1c2563999495df6ec2 100644 (file)
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -46,6 +46,13 @@
 #include <sound/compress_offload.h>
 #include <sound/compress_driver.h>
 
+/* struct snd_compr_codec_caps overflows the ioctl bit size for some
+ * architectures, so we need to disable the relevant ioctls.
+ */
+#if _IOC_SIZEBITS < 14
+#define COMPR_CODEC_CAPS_OVERFLOW
+#endif
+
 /* TODO:
  * - add substream support for multiple devices in case of
  *     SND_DYNAMIC_MINORS is not used
@@ -440,6 +447,7 @@ out:
        return retval;
 }
 
+#ifndef COMPR_CODEC_CAPS_OVERFLOW
 static int
 snd_compr_get_codec_caps(struct snd_compr_stream *stream, unsigned long arg)
 {
@@ -463,6 +471,7 @@ out:
        kfree(caps);
        return retval;
 }
+#endif /* !COMPR_CODEC_CAPS_OVERFLOW */
 
 /* revisit this with snd_pcm_preallocate_xxx */
 static int snd_compr_allocate_buffer(struct snd_compr_stream *stream,
@@ -801,9 +810,11 @@ static long snd_compr_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
        case _IOC_NR(SNDRV_COMPRESS_GET_CAPS):
                retval = snd_compr_get_caps(stream, arg);
                break;
+#ifndef COMPR_CODEC_CAPS_OVERFLOW
        case _IOC_NR(SNDRV_COMPRESS_GET_CODEC_CAPS):
                retval = snd_compr_get_codec_caps(stream, arg);
                break;
+#endif
        case _IOC_NR(SNDRV_COMPRESS_SET_PARAMS):
                retval = snd_compr_set_params(stream, arg);
                break;