[MIPS] RTLX: Handle copy_*_user return values.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 21 insertions, 25 deletions

diff --git a/arch/mips/kernel/rtlx.c b/arch/mips/kernel/rtlx.c
index 745649e15adc..e6e3047151a6 100644
--- a/arch/mips/kernel/rtlx.c
+++ b/arch/mips/kernel/rtlx.c
@@ -289,26 +289,11 @@ unsigned int rtlx_write_poll(int index)
 	return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size);
 }
 
-static inline void copy_to(void *dst, void *src, size_t count, int user)
-{
-	if (user)
-		copy_to_user(dst, src, count);
-	else
-		memcpy(dst, src, count);
-}
-
-static inline void copy_from(void *dst, void *src, size_t count, int user)
-{
-	if (user)
-		copy_from_user(dst, src, count);
-	else
-		memcpy(dst, src, count);
-}
-
-ssize_t rtlx_read(int index, void *buff, size_t count, int user)
+ssize_t rtlx_read(int index, void __user *buff, size_t count, int user)
 {
 	size_t lx_write, fl = 0L;
 	struct rtlx_channel *lx;
+	unsigned long failed;
 
 	if (rtlx == NULL)
 		return -ENOSYS;
@@ -327,11 +312,16 @@ ssize_t rtlx_read(int index, void *buff, size_t count, int user)
 	/* then how much from the read pointer onwards */
 	fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
 
-	copy_to(buff, lx->lx_buffer + lx->lx_read, fl, user);
+	failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
+	if (failed)
+		goto out;
 
 	/* and if there is anything left at the beginning of the buffer */
 	if (count - fl)
-		copy_to(buff + fl, lx->lx_buffer, count - fl, user);
+		failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);
+
+out:
+	count -= failed;
 
 	smp_wmb();
 	lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
@@ -341,7 +331,7 @@ ssize_t rtlx_read(int index, void *buff, size_t count, int user)
 	return count;
 }
 
-ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
+ssize_t rtlx_write(int index, const void __user *buffer, size_t count, int user)
 {
 	struct rtlx_channel *rt;
 	size_t rt_read;
@@ -363,11 +353,17 @@ ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
 	/* first bit from write pointer to the end of the buffer, or count */
 	fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
 
-	copy_from(rt->rt_buffer + rt->rt_write, buffer, fl, user);
+	failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
+	if (failed)
+		goto out;
 
 	/* if there's any left copy to the beginning of the buffer */
-	if (count - fl)
-		copy_from(rt->rt_buffer, buffer + fl, count - fl, user);
+	if (count - fl) {
+		failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
+	}
+
+out:
+	count -= cailed;
 
 	smp_wmb();
 	rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
@@ -426,7 +422,7 @@ static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
 		return 0;	// -EAGAIN makes cat whinge
 	}
 
-	return rtlx_read(minor, buffer, count, 1);
+	return rtlx_read(minor, buffer, count);
 }
 
 static ssize_t file_write(struct file *file, const char __user * buffer,
@@ -452,7 +448,7 @@ static ssize_t file_write(struct file *file, const char __user * buffer,
 			return ret;
 	}
 
-	return rtlx_write(minor, (void *)buffer, count, 1);
+	return rtlx_write(minor, buffer, count);
 }
 
 static const struct file_operations rtlx_fops = {