Commit 5a6e6e7c authored by Fabio M. De Francesco's avatar Fabio M. De Francesco Committed by David Sterba
Browse files

btrfs: zlib: replace kmap() with kmap_local_page() in zlib_decompress_bio() 



The use of kmap() is being deprecated in favor of kmap_local_page(). With
kmap_local_page(), the mapping is per thread, CPU local and not globally
visible.

Therefore, use kmap_local_page() / kunmap_local() in zlib_decompress_bio()
because in this function the mappings are per thread and are not visible
in other contexts.

Tested with xfstests on QEMU + KVM 32-bits VM with 4GB of RAM and
HIGHMEM64G enabled. This patch passes 26/26 tests of group "compress".

Suggested-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarFabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 718e5855

fs/btrfs/zlib.c

+5 −5
Original line number Diff line number Diff line
@@ -281,7 +281,7 @@ 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 = kmap(pages_in[page_in_index]);

	data_in = kmap_local_page(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;
@@ -303,7 +303,7 @@ 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]);

		kunmap_local(data_in);

		return -EIO;

	}

	while (workspace->strm.total_in < srclen) {
@@ -330,13 +330,13 @@ 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]);

			kunmap_local(data_in);

			page_in_index++;

			if (page_in_index >= total_pages_in) {

				data_in = NULL;

				break;

			}

			data_in = kmap(pages_in[page_in_index]);

			data_in = kmap_local_page(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);
@@ -349,7 +349,7 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 
done:

	zlib_inflateEnd(&workspace->strm);

	if (data_in)

		kunmap(pages_in[page_in_index]);

		kunmap_local(data_in);

	if (!ret)

		zero_fill_bio(cb->orig_bio);

	return ret;