btrfs: compression: drop kmap/kunmap from zlib

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/zlib.c b/fs/btrfs/zlib.c
index 2c792bc..5e18d7a 100644 (file)
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -126,7 +126,7 @@ int zlib_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[0] = out_page;
        nr_pages = 1;
 
@@ -148,26 +148,22 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
                                int i;
 
                                for (i = 0; i < in_buf_pages; i++) {
-                                       if (in_page) {
-                                               kunmap(in_page);
+                                       if (in_page)
                                                put_page(in_page);
-                                       }
                                        in_page = find_get_page(mapping,
                                                                start >> PAGE_SHIFT);
-                                       data_in = kmap(in_page);
+                                       data_in = page_address(in_page);
                                        memcpy(workspace->buf + i * PAGE_SIZE,
                                               data_in, PAGE_SIZE);
                                        start += PAGE_SIZE;
                                }
                                workspace->strm.next_in = workspace->buf;
                        } else {
-                               if (in_page) {
-                                       kunmap(in_page);
+                               if (in_page)
                                        put_page(in_page);
-                               }
                                in_page = find_get_page(mapping,
                                                        start >> PAGE_SHIFT);
-                               data_in = kmap(in_page);
+                               data_in = page_address(in_page);
                                start += PAGE_SIZE;
                                workspace->strm.next_in = data_in;
                        }
@@ -196,7 +192,6 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
                 * the stream end if required
                 */
                if (workspace->strm.avail_out == 0) {
-                       kunmap(out_page);
                        if (nr_pages == nr_dest_pages) {
                                out_page = NULL;
                                ret = -E2BIG;
@@ -207,7 +202,7 @@ int zlib_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;
                        nr_pages++;
                        workspace->strm.avail_out = PAGE_SIZE;
@@ -234,7 +229,6 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
                        goto out;
                } else if (workspace->strm.avail_out == 0) {
                        /* get another page for the stream end */
-                       kunmap(out_page);
                        if (nr_pages == nr_dest_pages) {
                                out_page = NULL;
                                ret = -E2BIG;
@@ -245,7 +239,7 @@ int zlib_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;
                        nr_pages++;
                        workspace->strm.avail_out = PAGE_SIZE;
@@ -264,13 +258,8 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
        *total_in = workspace->strm.total_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;
 }
 
@@ -289,7 +278,7 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
        u64 disk_start = cb->start;
        struct bio *orig_bio = cb->orig_bio;
 
-       data_in = kmap(pages_in[page_in_index]);
+       data_in = page_address(pages_in[page_in_index]);
        workspace->strm.next_in = data_in;
        workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
        workspace->strm.total_in = 0;
@@ -311,7 +300,6 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 
        if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
                pr_warn("BTRFS: inflateInit failed\n");
-               kunmap(pages_in[page_in_index]);
                return -EIO;
        }
        while (workspace->strm.total_in < srclen) {
@@ -339,13 +327,13 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 
                if (workspace->strm.avail_in == 0) {
                        unsigned long tmp;
-                       kunmap(pages_in[page_in_index]);
+
                        page_in_index++;
                        if (page_in_index >= total_pages_in) {
                                data_in = NULL;
                                break;
                        }
-                       data_in = kmap(pages_in[page_in_index]);
+                       data_in = page_address(pages_in[page_in_index]);
                        workspace->strm.next_in = data_in;
                        tmp = srclen - workspace->strm.total_in;
                        workspace->strm.avail_in = min(tmp,
@@ -358,8 +346,6 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
                ret = 0;
 done:
        zlib_inflateEnd(&workspace->strm);
-       if (data_in)
-               kunmap(pages_in[page_in_index]);
        if (!ret)
                zero_fill_bio(orig_bio);
        return ret;