Fedora Core 2.6.12-1.1398_FC4 kernel

[linux-2.6.git] / mm / usercopy.c

diff --git a/mm/usercopy.c b/mm/usercopy.c
index 0ca0c9c..a22b81f 100644 (file)
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -24,7 +24,8 @@
 /*
  * Get kernel address of the user page and pin it.
  */
-static inline struct page *pin_page(unsigned long addr, int write)
+static inline struct page *pin_page(unsigned long addr, int write,
+                                       unsigned long *pfn)
 {
        struct mm_struct *mm = current->mm ? : &init_mm;
        struct page *page = NULL;
@@ -34,13 +35,14 @@ static inline struct page *pin_page(unsigned long addr, int write)
         * Do a quick atomic lookup first - this is the fastpath.
         */
 retry:
-       page = follow_page(mm, addr, write);
+       page = follow_page_pfn(mm, addr, write, pfn);
        if (likely(page != NULL)) {
                if (!PageReserved(page))
                        get_page(page);
                return page;
        }
-
+       if (*pfn)
+               return NULL;
        /*
         * No luck - bad address or need to fault in the page:
         */
@@ -95,11 +97,12 @@ static int rw_vm(unsigned long addr, void *buf, int len, int write)
        /* ignore errors, just check how much was sucessfully transfered */
        while (len) {
                struct page *page = NULL;
+               unsigned long pfn = 0;
                int bytes, offset;
                void *maddr;
 
-               page = pin_page(addr, write);
-               if (!page)
+               page = pin_page(addr, write, &pfn);
+               if (!page && !pfn)
                        break;
 
                bytes = len;
@@ -107,7 +110,10 @@ static int rw_vm(unsigned long addr, void *buf, int len, int write)
                if (bytes > PAGE_SIZE-offset)
                        bytes = PAGE_SIZE-offset;
 
-               maddr = kmap_atomic(page, KM_USER_COPY);
+               if (page)
+                       maddr = kmap_atomic(page, KM_USER_COPY);
+               else
+                       maddr = kmap_atomic_nocache_pfn(pfn, KM_USER_COPY);
 
 #define HANDLE_TYPE(type) \
        case sizeof(type): *(type *)(maddr+offset) = *(type *)(buf); break;
@@ -134,7 +140,8 @@ static int rw_vm(unsigned long addr, void *buf, int len, int write)
 #undef HANDLE_TYPE
                }
                kunmap_atomic(maddr, KM_USER_COPY);
-               unpin_page(page);
+               if (page)
+                       unpin_page(page);
                len -= bytes;
                buf += bytes;
                addr += bytes;
@@ -158,10 +165,11 @@ static int str_vm(unsigned long addr, void *buf0, int len, int copy)
        /* ignore errors, just check how much was sucessfully transfered */
        while (len) {
                int bytes, offset, left, copied;
+               unsigned long pfn = 0;
                char *maddr;
 
-               page = pin_page(addr, copy == 2);
-               if (!page) {
+               page = pin_page(addr, copy == 2, &pfn);
+               if (!page && !pfn) {
                        spin_unlock(&mm->page_table_lock);
                        return -EFAULT;
                }
@@ -170,7 +178,10 @@ static int str_vm(unsigned long addr, void *buf0, int len, int copy)
                if (bytes > PAGE_SIZE-offset)
                        bytes = PAGE_SIZE-offset;
 
-               maddr = kmap_atomic(page, KM_USER_COPY);
+               if (page)
+                       maddr = kmap_atomic(page, KM_USER_COPY);
+               else
+                       maddr = kmap_atomic_nocache_pfn(pfn, KM_USER_COPY);
                if (copy == 2) {
                        memset(maddr + offset, 0, bytes);
                        copied = bytes;
@@ -184,7 +195,8 @@ static int str_vm(unsigned long addr, void *buf0, int len, int copy)
                }
                BUG_ON(bytes < 0 || copied < 0);
                kunmap_atomic(maddr, KM_USER_COPY);
-               unpin_page(page);
+               if (page)
+                       unpin_page(page);
                len -= copied;
                buf += copied;
                addr += copied;