Btrfs: Go back to kmaps instead of page_address in extent_buffers

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 19 insertions, 31 deletions

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index d2c733c68b4c..f150188f621c 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -1867,7 +1867,6 @@ sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
         if (!em || IS_ERR(em))
                 return 0;
 
-        // XXX(hch): block 0 is valid in some cases, e.g. XFS RT device
         if (em->block_start == EXTENT_MAP_INLINE ||
             em->block_start == EXTENT_MAP_HOLE)
                 return 0;
@@ -2199,10 +2198,9 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
                 WARN_ON(!PageUptodate(page));
 
                 cur = min(len, (PAGE_CACHE_SIZE - offset));
-                // kaddr = kmap_atomic(page, KM_USER0);
-                kaddr = page_address(page);
+                kaddr = kmap_atomic(page, KM_USER0);
                 memcpy(dst, kaddr + offset, cur);
-                // kunmap_atomic(kaddr, KM_USER0);
+                kunmap_atomic(kaddr, KM_USER0);
 
                 dst += cur;
                 len -= cur;
@@ -2237,8 +2235,7 @@ int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
                 *map_start = (i << PAGE_CACHE_SHIFT) - start_offset;
         }
 
-        // kaddr = kmap_atomic(eb->pages[i], km);
-        kaddr = page_address(extent_buffer_page(eb, i));
+        kaddr = kmap_atomic(extent_buffer_page(eb, i), km);
         *token = kaddr;
         *map = kaddr + offset;
         *map_len = PAGE_CACHE_SIZE - offset;
@@ -2248,7 +2245,7 @@ EXPORT_SYMBOL(map_extent_buffer);
 
 void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km)
 {
-        // kunmap_atomic(token, km);
+        kunmap_atomic(token, km);
 }
 EXPORT_SYMBOL(unmap_extent_buffer);
 
@@ -2278,10 +2275,9 @@ int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
 
                 cur = min(len, (PAGE_CACHE_SIZE - offset));
 
-                // kaddr = kmap_atomic(page, KM_USER0);
-                kaddr = page_address(page);
+                kaddr = kmap_atomic(page, KM_USER0);
                 ret = memcmp(ptr, kaddr + offset, cur);
-                // kunmap_atomic(kaddr, KM_USER0);
+                kunmap_atomic(kaddr, KM_USER0);
                 if (ret)
                         break;
 
@@ -2317,10 +2313,9 @@ void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
                 WARN_ON(!PageUptodate(page));
 
                 cur = min(len, PAGE_CACHE_SIZE - offset);
-                // kaddr = kmap_atomic(page, KM_USER0);
-                kaddr = page_address(page);
+                kaddr = kmap_atomic(page, KM_USER0);
                 memcpy(kaddr + offset, src, cur);
-                // kunmap_atomic(kaddr, KM_USER0);
+                kunmap_atomic(kaddr, KM_USER0);
 
                 src += cur;
                 len -= cur;
@@ -2352,10 +2347,9 @@ void memset_extent_buffer(struct extent_buffer *eb, char c,
                 WARN_ON(!PageUptodate(page));
 
                 cur = min(len, PAGE_CACHE_SIZE - offset);
-                // kaddr = kmap_atomic(page, KM_USER0);
-                kaddr = page_address(page);
+                kaddr = kmap_atomic(page, KM_USER0);
                 memset(kaddr + offset, c, cur);
-                // kunmap_atomic(kaddr, KM_USER0);
+                kunmap_atomic(kaddr, KM_USER0);
 
                 len -= cur;
                 offset = 0;
@@ -2388,10 +2382,9 @@ void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
 
                 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
 
-                // kaddr = kmap_atomic(page, KM_USER1);
-                kaddr = page_address(page);
+                kaddr = kmap_atomic(page, KM_USER1);
                 read_extent_buffer(src, kaddr + offset, src_offset, cur);
-                // kunmap_atomic(kaddr, KM_USER1);
+                kunmap_atomic(kaddr, KM_USER1);
 
                 src_offset += cur;
                 len -= cur;
@@ -2405,43 +2398,38 @@ static void move_pages(struct page *dst_page, struct page *src_page,
                        unsigned long dst_off, unsigned long src_off,
                        unsigned long len)
 {
-        // char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
-        char *dst_kaddr = page_address(dst_page);
+        char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
         if (dst_page == src_page) {
                 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
         } else {
-                // char *src_kaddr = kmap_atomic(src_page, KM_USER1);
-                char *src_kaddr = page_address(src_page);
+                char *src_kaddr = kmap_atomic(src_page, KM_USER1);
                 char *p = dst_kaddr + dst_off + len;
                 char *s = src_kaddr + src_off + len;
 
                 while (len--)
                         *--p = *--s;
 
-                // kunmap_atomic(src_kaddr, KM_USER1);
+                kunmap_atomic(src_kaddr, KM_USER1);
         }
-        // kunmap_atomic(dst_kaddr, KM_USER0);
+        kunmap_atomic(dst_kaddr, KM_USER0);
 }
 
 static void copy_pages(struct page *dst_page, struct page *src_page,
                        unsigned long dst_off, unsigned long src_off,
                        unsigned long len)
 {
-        //kmap_atomic(dst_page, KM_USER0);
-        char *dst_kaddr = page_address(dst_page);
+        char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
         char *src_kaddr;
 
         if (dst_page != src_page)
-                src_kaddr = page_address(src_page); // kmap_atomic(src_page, KM_USER1);
+                src_kaddr = kmap_atomic(src_page, KM_USER1);
         else
                 src_kaddr = dst_kaddr;
 
         memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
-        /*
         kunmap_atomic(dst_kaddr, KM_USER0);
         if (dst_page != src_page)
                 kunmap_atomic(src_kaddr, KM_USER1);
-        */
 }
 
 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
@@ -2537,7 +2525,7 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
 
                 cur = min(len, src_off_in_page + 1);
                 cur = min(cur, dst_off_in_page + 1);
-// printk("move pages orig dst %lu src %lu len %lu, this %lu %lu %lu\n", dst_offset, src_offset, len, dst_off_in_page - cur + 1, src_off_in_page - cur + 1, cur);
+
                 move_pages(extent_buffer_page(dst, dst_i),
                            extent_buffer_page(dst, src_i),
                            dst_off_in_page - cur + 1,