Merge tag 'v2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[mv-sheeva.git] / fs / btrfs / lzo.c

diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index cc9b450399df29d94c670391c9772bc06761c051..a178f5ebea78986c3d1614b5ffed51797dd1faa5 100644 (file)
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -280,6 +280,7 @@ static int lzo_decompress_biovec(struct list_head *ws,
        unsigned long tot_out;
        unsigned long tot_len;
        char *buf;
+       bool may_late_unmap, need_unmap;
 
        data_in = kmap(pages_in[0]);
        tot_len = read_compress_length(data_in);
@@ -300,11 +301,13 @@ static int lzo_decompress_biovec(struct list_head *ws,
 
                tot_in += in_len;
                working_bytes = in_len;
+               may_late_unmap = need_unmap = false;
 
                /* fast path: avoid using the working buffer */
                if (in_page_bytes_left >= in_len) {
                        buf = data_in + in_offset;
                        bytes = in_len;
+                       may_late_unmap = true;
                        goto cont;
                }
 
@@ -329,14 +332,17 @@ cont:
                                if (working_bytes == 0 && tot_in >= tot_len)
                                        break;
 
-                               kunmap(pages_in[page_in_index]);
-                               page_in_index++;
-                               if (page_in_index >= total_pages_in) {
+                               if (page_in_index + 1 >= total_pages_in) {
                                        ret = -1;
-                                       data_in = NULL;
                                        goto done;
                                }
-                               data_in = kmap(pages_in[page_in_index]);
+
+                               if (may_late_unmap)
+                                       need_unmap = true;
+                               else
+                                       kunmap(pages_in[page_in_index]);
+
+                               data_in = kmap(pages_in[++page_in_index]);
 
                                in_page_bytes_left = PAGE_CACHE_SIZE;
                                in_offset = 0;
@@ -346,6 +352,8 @@ cont:
                out_len = lzo1x_worst_compress(PAGE_CACHE_SIZE);
                ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
                                            &out_len);
+               if (need_unmap)
+                       kunmap(pages_in[page_in_index - 1]);
                if (ret != LZO_E_OK) {
                        printk(KERN_WARNING "btrfs decompress failed\n");
                        ret = -1;
@@ -363,8 +371,7 @@ cont:
                        break;
        }
 done:
-       if (data_in)
-               kunmap(pages_in[page_in_index]);
+       kunmap(pages_in[page_in_index]);
        return ret;
 }