x86, mm: pass in 'total' to __copy_from_user_*nocache()

Impact: cleanup, enable future change

Add a 'total bytes copied' parameter to __copy_from_user_*nocache(),
and update all the callsites.

The parameter is not used yet - architecture code can use it to
more intelligently decide whether the copy should be cached or
non-temporal.

Cc: Salman Qazi <sqazi@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

6 files changed, 14 insertions, 13 deletions

diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h
index 5e06259e90e5..a0ba61386972 100644
--- a/arch/x86/include/asm/uaccess_32.h
+++ b/arch/x86/include/asm/uaccess_32.h
@@ -157,7 +157,7 @@ __copy_from_user(void *to, const void __user *from, unsigned long n)
 }
 
 static __always_inline unsigned long __copy_from_user_nocache(void *to,
-                                const void __user *from, unsigned long n)
+                const void __user *from, unsigned long n, unsigned long total)
 {
         might_fault();
         if (__builtin_constant_p(n)) {
@@ -180,7 +180,7 @@ static __always_inline unsigned long __copy_from_user_nocache(void *to,
 
 static __always_inline unsigned long
 __copy_from_user_inatomic_nocache(void *to, const void __user *from,
-                                  unsigned long n)
+                                  unsigned long n, unsigned long total)
 {
        return __copy_from_user_ll_nocache_nozero(to, from, n);
 }
diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index 987a2c10fe20..a748253db0c9 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -189,7 +189,7 @@ extern long __copy_user_nocache(void *dst, const void __user *src,
                                 unsigned size, int zerorest);
 
 static inline int __copy_from_user_nocache(void *dst, const void __user *src,
-                                           unsigned size)
+                                   unsigned size, unsigned long total)
 {
         might_sleep();
         /*
@@ -205,8 +205,7 @@ static inline int __copy_from_user_nocache(void *dst, const void __user *src,
 }
 
 static inline int __copy_from_user_inatomic_nocache(void *dst,
-                                                    const void __user *src,
-                                                    unsigned size)
+            const void __user *src, unsigned size, unsigned total)
 {
         if (likely(size >= PAGE_SIZE))
                 return __copy_user_nocache(dst, src, size, 0);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 818576654092..6b209db8370d 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -215,7 +215,7 @@ fast_user_write(struct io_mapping *mapping,
 
         vaddr_atomic = io_mapping_map_atomic_wc(mapping, page_base);
         unwritten = __copy_from_user_inatomic_nocache(vaddr_atomic + page_offset,
-                                                      user_data, length);
+                                                      user_data, length, length);
         io_mapping_unmap_atomic(vaddr_atomic);
         if (unwritten)
                 return -EFAULT;
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 6b58367d145e..6f3c603b0d67 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -41,13 +41,13 @@ static inline void pagefault_enable(void)
 #ifndef ARCH_HAS_NOCACHE_UACCESS
 
 static inline unsigned long __copy_from_user_inatomic_nocache(void *to,
-                                const void __user *from, unsigned long n)
+                const void __user *from, unsigned long n, unsigned long total)
 {
         return __copy_from_user_inatomic(to, from, n);
 }
 
 static inline unsigned long __copy_from_user_nocache(void *to,
-                                const void __user *from, unsigned long n)
+                const void __user *from, unsigned long n, unsigned long total)
 {
         return __copy_from_user(to, from, n);
 }
diff --git a/mm/filemap.c b/mm/filemap.c
index 23acefe51808..60fd56772cc6 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1816,14 +1816,14 @@ EXPORT_SYMBOL(file_remove_suid);
 static size_t __iovec_copy_from_user_inatomic(char *vaddr,
                         const struct iovec *iov, size_t base, size_t bytes)
 {
-        size_t copied = 0, left = 0;
+        size_t copied = 0, left = 0, total = bytes;
 
         while (bytes) {
                 char __user *buf = iov->iov_base + base;
                 int copy = min(bytes, iov->iov_len - base);
 
                 base = 0;
-                left = __copy_from_user_inatomic_nocache(vaddr, buf, copy);
+                left = __copy_from_user_inatomic_nocache(vaddr, buf, copy, total);
                 copied += copy;
                 bytes -= copy;
                 vaddr += copy;
@@ -1851,8 +1851,9 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
         if (likely(i->nr_segs == 1)) {
                 int left;
                 char __user *buf = i->iov->iov_base + i->iov_offset;
+
                 left = __copy_from_user_inatomic_nocache(kaddr + offset,
-                                                        buf, bytes);
+                                                        buf, bytes, bytes);
                 copied = bytes - left;
         } else {
                 copied = __iovec_copy_from_user_inatomic(kaddr + offset,
@@ -1880,7 +1881,8 @@ size_t iov_iter_copy_from_user(struct page *page,
         if (likely(i->nr_segs == 1)) {
                 int left;
                 char __user *buf = i->iov->iov_base + i->iov_offset;
-                left = __copy_from_user_nocache(kaddr + offset, buf, bytes);
+
+                left = __copy_from_user_nocache(kaddr + offset, buf, bytes, bytes);
                 copied = bytes - left;
         } else {
                 copied = __iovec_copy_from_user_inatomic(kaddr + offset,
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 0c04615651b7..bf54f8a2cf1d 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -354,7 +354,7 @@ __xip_file_write(struct file *filp, const char __user *buf,
                         break;
 
                 copied = bytes -
-                        __copy_from_user_nocache(xip_mem + offset, buf, bytes);
+                        __copy_from_user_nocache(xip_mem + offset, buf, bytes, bytes);
 
                 if (likely(copied > 0)) {
                         status = copied;