btrfs: Extract duplicate decompress code

Add a common function to copy decompressed data from working buffer
to bio pages.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

1 files changed, 6 insertions, 95 deletions

diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index 523b144e2aec..cc9b450399df 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -260,12 +260,10 @@ static int lzo_decompress_biovec(struct list_head *ws,
                                  size_t srclen)
 {
         struct workspace *workspace = list_entry(ws, struct workspace, list);
-        int ret = 0;
+        int ret = 0, ret2;
         char *data_in;
-        unsigned long page_bytes_left;
         unsigned long page_in_index = 0;
         unsigned long page_out_index = 0;
-        struct page *page_out;
         unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
                                         PAGE_CACHE_SIZE;
         unsigned long buf_start;
@@ -273,9 +271,6 @@ static int lzo_decompress_biovec(struct list_head *ws,
         unsigned long bytes;
         unsigned long working_bytes;
         unsigned long pg_offset;
-        unsigned long start_byte;
-        unsigned long current_buf_start;
-        char *kaddr;
 
         size_t in_len;
         size_t out_len;
@@ -295,8 +290,6 @@ static int lzo_decompress_biovec(struct list_head *ws,
         in_page_bytes_left = PAGE_CACHE_SIZE - LZO_LEN;
 
         tot_out = 0;
-        page_out = bvec[0].bv_page;
-        page_bytes_left = PAGE_CACHE_SIZE;
         pg_offset = 0;
 
         while (tot_in < tot_len) {
@@ -359,97 +352,15 @@ cont:
                         break;
                 }
 
-                /*
-                 * buf start is the byte offset we're of the start of
-                 * our workspace buffer
-                 */
                 buf_start = tot_out;
-
-                /* tot_out is the last byte of the workspace buffer */
                 tot_out += out_len;
 
-                working_bytes = tot_out - buf_start;
-
-                /*
-                 * start_byte is the first byte of the page we're currently
-                 * copying into relative to the start of the compressed data.
-                 */
-                start_byte = page_offset(page_out) - disk_start;
-
-                if (working_bytes == 0) {
-                        /* we didn't make progress in this inflate
-                         * call, we're done
-                         */
+                ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
+                                                 tot_out, disk_start,
+                                                 bvec, vcnt,
+                                                 &page_out_index, &pg_offset);
+                if (ret2 == 0)
                         break;
-                }
-
-                /* we haven't yet hit data corresponding to this page */
-                if (tot_out <= start_byte)
-                        continue;
-
-                /*
-                 * the start of the data we care about is offset into
-                 * the middle of our working buffer
-                 */
-                if (tot_out > start_byte && buf_start < start_byte) {
-                        buf_offset = start_byte - buf_start;
-                        working_bytes -= buf_offset;
-                } else {
-                        buf_offset = 0;
-                }
-                current_buf_start = buf_start;
-
-                /* copy bytes from the working buffer into the pages */
-                while (working_bytes > 0) {
-                        bytes = min(PAGE_CACHE_SIZE - pg_offset,
-                                    PAGE_CACHE_SIZE - buf_offset);
-                        bytes = min(bytes, working_bytes);
-                        kaddr = kmap_atomic(page_out, KM_USER0);
-                        memcpy(kaddr + pg_offset, workspace->buf + buf_offset,
-                               bytes);
-                        kunmap_atomic(kaddr, KM_USER0);
-                        flush_dcache_page(page_out);
-
-                        pg_offset += bytes;
-                        page_bytes_left -= bytes;
-                        buf_offset += bytes;
-                        working_bytes -= bytes;
-                        current_buf_start += bytes;
-
-                        /* check if we need to pick another page */
-                        if (page_bytes_left == 0) {
-                                page_out_index++;
-                                if (page_out_index >= vcnt) {
-                                        ret = 0;
-                                        goto done;
-                                }
-
-                                page_out = bvec[page_out_index].bv_page;
-                                pg_offset = 0;
-                                page_bytes_left = PAGE_CACHE_SIZE;
-                                start_byte = page_offset(page_out) - disk_start;
-
-                                /*
-                                 * make sure our new page is covered by this
-                                 * working buffer
-                                 */
-                                if (tot_out <= start_byte)
-                                        break;
-
-                                /* the next page in the biovec might not
-                                 * be adjacent to the last page, but it
-                                 * might still be found inside this working
-                                 * buffer.  bump our offset pointer
-                                 */
-                                if (tot_out > start_byte &&
-                                    current_buf_start < start_byte) {
-                                        buf_offset = start_byte - buf_start;
-                                        working_bytes = tot_out - start_byte;
-                                        current_buf_start = buf_start +
-                                                buf_offset;
-                                }
-                        }
-                }
         }
 done:
         if (data_in)