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

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

3 files changed, 37 insertions, 31 deletions

diff --git a/arch/mips/kernel/kspd.c b/arch/mips/kernel/kspd.c
index 241ee7a2906e..29eadd404fa5 100644
--- a/arch/mips/kernel/kspd.c
+++ b/arch/mips/kernel/kspd.c
@@ -191,6 +191,8 @@ void sp_work_handle_request(void)
         struct mtsp_syscall_generic generic;
         struct mtsp_syscall_ret ret;
         struct kspd_notifications *n;
+        unsigned long written;
+        mm_segment_t old_fs;
         struct timeval tv;
         struct timezone tz;
         int cmd;
@@ -201,7 +203,11 @@ void sp_work_handle_request(void)
 
         ret.retval = -1;
 
-        if (!rtlx_read(RTLX_CHANNEL_SYSIO, &sc, sizeof(struct mtsp_syscall), 0)) {
+        old_fs = get_fs();
+        set_fs(KERNEL_DS);
+
+        if (!rtlx_read(RTLX_CHANNEL_SYSIO, &sc, sizeof(struct mtsp_syscall))) {
+                set_fs(old_fs);
                 printk(KERN_ERR "Expected request but nothing to read\n");
                 return;
         }
@@ -209,7 +215,8 @@ void sp_work_handle_request(void)
         size = sc.size;
 
         if (size) {
-                if (!rtlx_read(RTLX_CHANNEL_SYSIO, &generic, size, 0)) {
+                if (!rtlx_read(RTLX_CHANNEL_SYSIO, &generic, size)) {
+                        set_fs(old_fs);
                         printk(KERN_ERR "Expected request but nothing to read\n");
                         return;
                 }
@@ -282,8 +289,11 @@ void sp_work_handle_request(void)
         if (vpe_getuid(SP_VPE))
                 sp_setfsuidgid( 0, 0);
 
-        if ((rtlx_write(RTLX_CHANNEL_SYSIO, &ret, sizeof(struct mtsp_syscall_ret), 0))
-            < sizeof(struct mtsp_syscall_ret))
+        old_fs = get_fs();
+        set_fs(KERNEL_DS);
+        written = rtlx_write(RTLX_CHANNEL_SYSIO, &ret, sizeof(ret));
+        set_fs(old_fs);
+        if (written < sizeof(ret))
                 printk("KSPD: sp_work_handle_request failed to send to SP\n");
 }
 
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 = {
diff --git a/include/asm-mips/rtlx.h b/include/asm-mips/rtlx.h
index 59162f74a798..65778c890a62 100644
--- a/include/asm-mips/rtlx.h
+++ b/include/asm-mips/rtlx.h
@@ -23,8 +23,8 @@
 
 extern int rtlx_open(int index, int can_sleep);
 extern int rtlx_release(int index);
-extern ssize_t rtlx_read(int index, void *buff, size_t count, int user);
-extern ssize_t rtlx_write(int index, void *buffer, size_t count, int user);
+extern ssize_t rtlx_read(int index, void __user *buff, size_t count);
+extern ssize_t rtlx_write(int index, const void __user *buffer, size_t count);
 extern unsigned int rtlx_read_poll(int index, int can_sleep);
 extern unsigned int rtlx_write_poll(int index);