btrfs: compression: drop kmap/kunmap from zstd

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/zstd.c b/fs/btrfs/zstd.c
index 9451d2b..200ba08 100644 (file)
--- a/fs/btrfs/zstd.c
+++ b/fs/btrfs/zstd.c
@@ -399,7 +399,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
 
        /* map in the first page of input data */
        in_page = find_get_page(mapping, start >> PAGE_SHIFT);
-       workspace->in_buf.src = kmap(in_page);
+       workspace->in_buf.src = page_address(in_page);
        workspace->in_buf.pos = 0;
        workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
 
@@ -411,7 +411,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
                goto out;
        }
        pages[nr_pages++] = out_page;
-       workspace->out_buf.dst = kmap(out_page);
+       workspace->out_buf.dst = page_address(out_page);
        workspace->out_buf.pos = 0;
        workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
 
@@ -446,7 +446,6 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
                if (workspace->out_buf.pos == workspace->out_buf.size) {
                        tot_out += PAGE_SIZE;
                        max_out -= PAGE_SIZE;
-                       kunmap(out_page);
                        if (nr_pages == nr_dest_pages) {
                                out_page = NULL;
                                ret = -E2BIG;
@@ -458,7 +457,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
                                goto out;
                        }
                        pages[nr_pages++] = out_page;
-                       workspace->out_buf.dst = kmap(out_page);
+                       workspace->out_buf.dst = page_address(out_page);
                        workspace->out_buf.pos = 0;
                        workspace->out_buf.size = min_t(size_t, max_out,
                                                        PAGE_SIZE);
@@ -473,13 +472,12 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
                /* Check if we need more input */
                if (workspace->in_buf.pos == workspace->in_buf.size) {
                        tot_in += PAGE_SIZE;
-                       kunmap(in_page);
                        put_page(in_page);
 
                        start += PAGE_SIZE;
                        len -= PAGE_SIZE;
                        in_page = find_get_page(mapping, start >> PAGE_SHIFT);
-                       workspace->in_buf.src = kmap(in_page);
+                       workspace->in_buf.src = page_address(in_page);
                        workspace->in_buf.pos = 0;
                        workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
                }
@@ -506,7 +504,6 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
 
                tot_out += PAGE_SIZE;
                max_out -= PAGE_SIZE;
-               kunmap(out_page);
                if (nr_pages == nr_dest_pages) {
                        out_page = NULL;
                        ret = -E2BIG;
@@ -518,7 +515,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
                        goto out;
                }
                pages[nr_pages++] = out_page;
-               workspace->out_buf.dst = kmap(out_page);
+               workspace->out_buf.dst = page_address(out_page);
                workspace->out_buf.pos = 0;
                workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
        }
@@ -534,12 +531,8 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
 out:
        *out_pages = nr_pages;
        /* Cleanup */
-       if (in_page) {
-               kunmap(in_page);
+       if (in_page)
                put_page(in_page);
-       }
-       if (out_page)
-               kunmap(out_page);
        return ret;
 }
 
@@ -565,7 +558,7 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
                goto done;
        }
 
-       workspace->in_buf.src = kmap(pages_in[page_in_index]);
+       workspace->in_buf.src = page_address(pages_in[page_in_index]);
        workspace->in_buf.pos = 0;
        workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
 
@@ -601,14 +594,14 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
                        break;
 
                if (workspace->in_buf.pos == workspace->in_buf.size) {
-                       kunmap(pages_in[page_in_index++]);
+                       page_in_index++;
                        if (page_in_index >= total_pages_in) {
                                workspace->in_buf.src = NULL;
                                ret = -EIO;
                                goto done;
                        }
                        srclen -= PAGE_SIZE;
-                       workspace->in_buf.src = kmap(pages_in[page_in_index]);
+                       workspace->in_buf.src = page_address(pages_in[page_in_index]);
                        workspace->in_buf.pos = 0;
                        workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
                }
@@ -616,8 +609,6 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
        ret = 0;
        zero_fill_bio(orig_bio);
 done:
-       if (workspace->in_buf.src)
-               kunmap(pages_in[page_in_index]);
        return ret;
 }