[PATCH] sound/oss/emu10k1: handle userspace copy errors

Propagate copy_to/from_user() errors back through callers.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

sound/oss/emu10k1/passthrough.c

@@ -162,12 +162,15 @@ ssize_t emu10k1_pt_write(struct file *file, const char __user *buffer, size_t co
 
 		DPD(3, "prepend size %d, prepending %d bytes\n", pt->prepend_size, needed);
 		if (count < needed) {
-			copy_from_user(pt->buf + pt->prepend_size, buffer, count);
+			if (copy_from_user(pt->buf + pt->prepend_size,
+					   buffer, count))
+				return -EFAULT;
 			pt->prepend_size += count;
 			DPD(3, "prepend size now %d\n", pt->prepend_size);
 			return count;
 		}
-		copy_from_user(pt->buf + pt->prepend_size, buffer, needed);
+		if (copy_from_user(pt->buf + pt->prepend_size, buffer, needed))
+			return -EFAULT;
 		r = pt_putblock(wave_dev, (u16 *) pt->buf, nonblock);
 		if (r)
 			return r;
@@ -178,7 +181,8 @@ ssize_t emu10k1_pt_write(struct file *file, const char __user *buffer, size_t co
 	blocks_copied = 0;
 	while (blocks > 0) {
 		u16 __user *bufptr = (u16 __user *) buffer + (bytes_copied/2);
-		copy_from_user(pt->buf, bufptr, PT_BLOCKSIZE);
+		if (copy_from_user(pt->buf, bufptr, PT_BLOCKSIZE))
+			return -EFAULT;
 		r = pt_putblock(wave_dev, (u16 *)pt->buf, nonblock);
 		if (r) {
 			if (bytes_copied)
@@ -193,7 +197,8 @@ ssize_t emu10k1_pt_write(struct file *file, const char __user *buffer, size_t co
 	i = count - bytes_copied;
 	if (i) {
 		pt->prepend_size = i;
-		copy_from_user(pt->buf, buffer + bytes_copied, i);
+		if (copy_from_user(pt->buf, buffer + bytes_copied, i))
+			return -EFAULT;
 		bytes_copied += i;
 		DPD(3, "filling prepend buffer with %d bytes", i);
 	}