metag/usercopy: Add early abort to copy_to_user

[android-x86/kernel.git] / arch / metag / lib / usercopy.c

diff --git a/arch/metag/lib/usercopy.c b/arch/metag/lib/usercopy.c
index a6ced96..714d856 100644 (file)
--- a/arch/metag/lib/usercopy.c
+++ b/arch/metag/lib/usercopy.c
@@ -538,23 +538,31 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
        if ((unsigned long) src & 1) {
                __asm_copy_to_user_1(dst, src, retn);
                n--;
+               if (retn)
+                       return retn + n;
        }
        if ((unsigned long) dst & 1) {
                /* Worst case - byte copy */
                while (n > 0) {
                        __asm_copy_to_user_1(dst, src, retn);
                        n--;
+                       if (retn)
+                               return retn + n;
                }
        }
        if (((unsigned long) src & 2) && n >= 2) {
                __asm_copy_to_user_2(dst, src, retn);
                n -= 2;
+               if (retn)
+                       return retn + n;
        }
        if ((unsigned long) dst & 2) {
                /* Second worst case - word copy */
                while (n >= 2) {
                        __asm_copy_to_user_2(dst, src, retn);
                        n -= 2;
+                       if (retn)
+                               return retn + n;
                }
        }
 
@@ -569,6 +577,8 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
                while (n >= 8) {
                        __asm_copy_to_user_8x64(dst, src, retn);
                        n -= 8;
+                       if (retn)
+                               return retn + n;
                }
        }
        if (n >= RAPF_MIN_BUF_SIZE) {
@@ -581,6 +591,8 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
                while (n >= 8) {
                        __asm_copy_to_user_8x64(dst, src, retn);
                        n -= 8;
+                       if (retn)
+                               return retn + n;
                }
        }
 #endif
@@ -588,11 +600,15 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
        while (n >= 16) {
                __asm_copy_to_user_16(dst, src, retn);
                n -= 16;
+               if (retn)
+                       return retn + n;
        }
 
        while (n >= 4) {
                __asm_copy_to_user_4(dst, src, retn);
                n -= 4;
+               if (retn)
+                       return retn + n;
        }
 
        switch (n) {
@@ -609,6 +625,10 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
                break;
        }
 
+       /*
+        * If we get here, retn correctly reflects the number of failing
+        * bytes.
+        */
        return retn;
 }
 EXPORT_SYMBOL(__copy_user);