Messages in this thread Patch in this message | | | From | "Fabio M. De Francesco" <> | Subject | [RFC PATCH v2 1/3] btrfs: Convert zlib_decompress_bio() to use kmap_local_page() | Date | Fri, 17 Jun 2022 14:05:36 +0200 |
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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: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> --- fs/btrfs/zlib.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index 767a0c6c9694..770c4c6bbaef 100644 --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -287,7 +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 = 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; @@ -309,7 +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]); + kunmap_local(data_in); return -EIO; } while (workspace->strm.total_in < srclen) { @@ -336,13 +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]); + 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); @@ -355,7 +355,7 @@ 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; -- 2.36.1
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