[PATCH 3.16 08/63] ALSA: compress: add support for 32bit calls in a 64bit kernel

From: Ben Hutchings
Date: Wed Jan 08 2020 - 14:49:36 EST


3.16.81-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Ravindra Lokhande <rlokhande@xxxxxxxxxx>

commit c10368897e104c008c610915a218f0fe5fa4ec96 upstream.

Compress offload does not support ioctl calls from a 32bit userspace
in a 64 bit kernel. This patch adds support for ioctls from a 32bit
userspace in a 64bit kernel

Signed-off-by: Ravindra Lokhande <rlokhande@xxxxxxxxxx>
Acked-by: Vinod Koul <vinod.koul@xxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
sound/core/compress_offload.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -38,6 +38,7 @@
#include <linux/uio.h>
#include <linux/uaccess.h>
#include <linux/module.h>
+#include <linux/compat.h>
#include <sound/core.h>
#include <sound/initval.h>
#include <sound/compress_params.h>
@@ -864,6 +865,15 @@ static long snd_compr_ioctl(struct file
return retval;
}

+/* support of 32bit userspace on 64bit platforms */
+#ifdef CONFIG_COMPAT
+static long snd_compr_ioctl_compat(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ return snd_compr_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
static const struct file_operations snd_compr_file_ops = {
.owner = THIS_MODULE,
.open = snd_compr_open,
@@ -871,6 +881,9 @@ static const struct file_operations snd_
.write = snd_compr_write,
.read = snd_compr_read,
.unlocked_ioctl = snd_compr_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = snd_compr_ioctl_compat,
+#endif
.mmap = snd_compr_mmap,
.poll = snd_compr_poll,
};