btrfs: compression: drop kmap/kunmap from lzo

As we don't use highmem pages anymore, drop the kmap/kunmap. The kmap is
simply page_address and kunmap is a no-op.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index 2bebb60..576a0e6 100644 (file)
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -140,7 +140,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
        *total_in = 0;
 
        in_page = find_get_page(mapping, start >> PAGE_SHIFT);
-       data_in = kmap(in_page);
+       data_in = page_address(in_page);
 
        /*
         * store the size of all chunks of compressed data in
@@ -151,7 +151,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
                ret = -ENOMEM;
                goto out;
        }
-       cpage_out = kmap(out_page);
+       cpage_out = page_address(out_page);
        out_offset = LZO_LEN;
        tot_out = LZO_LEN;
        pages[0] = out_page;
@@ -209,7 +209,6 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
                                if (out_len == 0 && tot_in >= len)
                                        break;
 
-                               kunmap(out_page);
                                if (nr_pages == nr_dest_pages) {
                                        out_page = NULL;
                                        ret = -E2BIG;
@@ -221,7 +220,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
                                        ret = -ENOMEM;
                                        goto out;
                                }
-                               cpage_out = kmap(out_page);
+                               cpage_out = page_address(out_page);
                                pages[nr_pages++] = out_page;
 
                                pg_bytes_left = PAGE_SIZE;
@@ -243,12 +242,11 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
                        break;
 
                bytes_left = len - tot_in;
-               kunmap(in_page);
                put_page(in_page);
 
                start += PAGE_SIZE;
                in_page = find_get_page(mapping, start >> PAGE_SHIFT);
-               data_in = kmap(in_page);
+               data_in = page_address(in_page);
                in_len = min(bytes_left, PAGE_SIZE);
        }
 
@@ -258,22 +256,17 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
        }
 
        /* store the size of all chunks of compressed data */
-       sizes_ptr = kmap_local_page(pages[0]);
+       sizes_ptr = page_address(pages[0]);
        write_compress_length(sizes_ptr, tot_out);
-       kunmap_local(sizes_ptr);
 
        ret = 0;
        *total_out = tot_out;
        *total_in = tot_in;
 out:
        *out_pages = nr_pages;
-       if (out_page)
-               kunmap(out_page);
 
-       if (in_page) {
-               kunmap(in_page);
+       if (in_page)
                put_page(in_page);
-       }
 
        return ret;
 }
@@ -299,12 +292,11 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
        unsigned long tot_out;
        unsigned long tot_len;
        char *buf;
-       bool may_late_unmap, need_unmap;
        struct page **pages_in = cb->compressed_pages;
        u64 disk_start = cb->start;
        struct bio *orig_bio = cb->orig_bio;
 
-       data_in = kmap(pages_in[0]);
+       data_in = page_address(pages_in[0]);
        tot_len = read_compress_length(data_in);
        /*
         * Compressed data header check.
@@ -345,13 +337,11 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 
                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;
                }
 
@@ -381,12 +371,8 @@ cont:
                                        goto done;
                                }
 
-                               if (may_late_unmap)
-                                       need_unmap = true;
-                               else
-                                       kunmap(pages_in[page_in_index]);
-
-                               data_in = kmap(pages_in[++page_in_index]);
+                               page_in_index++;
+                               data_in = page_address(pages_in[page_in_index]);
 
                                in_page_bytes_left = PAGE_SIZE;
                                in_offset = 0;
@@ -396,8 +382,6 @@ cont:
                out_len = max_segment_len;
                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) {
                        pr_warn("BTRFS: decompress failed\n");
                        ret = -EIO;
@@ -413,7 +397,6 @@ cont:
                        break;
        }
 done:
-       kunmap(pages_in[page_in_index]);
        if (!ret)
                zero_fill_bio(orig_bio);
        return ret;
@@ -466,7 +449,7 @@ int lzo_decompress(struct list_head *ws, unsigned char *data_in,
        destlen = min_t(unsigned long, destlen, PAGE_SIZE);
        bytes = min_t(unsigned long, destlen, out_len - start_byte);
 
-       kaddr = kmap_local_page(dest_page);
+       kaddr = page_address(dest_page);
        memcpy(kaddr, workspace->buf + start_byte, bytes);
 
        /*
@@ -476,7 +459,6 @@ int lzo_decompress(struct list_head *ws, unsigned char *data_in,
         */
        if (bytes < destlen)
                memset(kaddr+bytes, 0, destlen-bytes);
-       kunmap_local(kaddr);
 out:
        return ret;
 }