[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 = {