Revert "btrfs: compression: drop kmap/kunmap from zlib"

This reverts commit 696ab562e6df9fbafd6052d8ce4aafcb2ed16069.

The kmaps in compression code are still needed and cause crashes on
32bit machines (ARM, x86). Reproducible eg. by running fstest btrfs/004
with enabled LZO or ZSTD compression.

Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index 8afa900..767a0c6 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 = page_address(out_page);
+       cpage_out = kmap(out_page);
        pages[0] = out_page;
        nr_pages = 1;
 
@@ -148,22 +148,26 @@ 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)
+                                       if (in_page) {
+                                               kunmap(in_page);
                                                put_page(in_page);
+                                       }
                                        in_page = find_get_page(mapping,
                                                                start >> PAGE_SHIFT);
-                                       data_in = page_address(in_page);
+                                       data_in = kmap(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)
+                               if (in_page) {
+                                       kunmap(in_page);
                                        put_page(in_page);
+                               }
                                in_page = find_get_page(mapping,
                                                        start >> PAGE_SHIFT);
-                               data_in = page_address(in_page);
+                               data_in = kmap(in_page);
                                start += PAGE_SIZE;
                                workspace->strm.next_in = data_in;
                        }
@@ -192,6 +196,7 @@ 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;
@@ -202,7 +207,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
                                ret = -ENOMEM;
                                goto out;
                        }
-                       cpage_out = page_address(out_page);
+                       cpage_out = kmap(out_page);
                        pages[nr_pages] = out_page;
                        nr_pages++;
                        workspace->strm.avail_out = PAGE_SIZE;
@@ -229,6 +234,7 @@ 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;
@@ -239,7 +245,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
                                ret = -ENOMEM;
                                goto out;
                        }
-                       cpage_out = page_address(out_page);
+                       cpage_out = kmap(out_page);
                        pages[nr_pages] = out_page;
                        nr_pages++;
                        workspace->strm.avail_out = PAGE_SIZE;
@@ -258,8 +264,13 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
        *total_in = workspace->strm.total_in;
 out:
        *out_pages = nr_pages;
-       if (in_page)
+       if (out_page)
+               kunmap(out_page);
+
+       if (in_page) {
+               kunmap(in_page);
                put_page(in_page);
+       }
        return ret;
 }
 
@@ -276,7 +287,7 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
        unsigned long buf_start;
        struct page **pages_in = cb->compressed_pages;
 
-       data_in = page_address(pages_in[page_in_index]);
+       data_in = kmap(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;
@@ -298,6 +309,7 @@ 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) {
@@ -324,13 +336,13 @@ 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 = page_address(pages_in[page_in_index]);
+                       data_in = kmap(pages_in[page_in_index]);
                        workspace->strm.next_in = data_in;
                        tmp = srclen - workspace->strm.total_in;
                        workspace->strm.avail_in = min(tmp, PAGE_SIZE);
@@ -342,6 +354,8 @@ 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(cb->orig_bio);
        return ret;