On Tue, Feb 16, 2021 at 06:48:23PM -0800, ira.weiny@xxxxxxxxx wrote: > --- a/fs/btrfs/lzo.c > +++ b/fs/btrfs/lzo.c > @@ -118,7 +118,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping, > struct workspace *workspace = list_entry(ws, struct workspace, list); > int ret = 0; > char *data_in; > - char *cpage_out; > + char *cpage_out, *sizes_ptr; > int nr_pages = 0; > struct page *in_page = NULL; > struct page *out_page = NULL; > @@ -258,10 +258,9 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping, > } > > /* store the size of all chunks of compressed data */ > - cpage_out = kmap(pages[0]); > - write_compress_length(cpage_out, tot_out); > - > - kunmap(pages[0]); > + sizes_ptr = kmap_local_page(pages[0]); > + write_compress_length(sizes_ptr, tot_out); > + kunmap_local(sizes_ptr); Why is not cpage_out reused for this mapping? I don't see any reason for another temporary variable, cpage_out is not used at this point.
