Commit 448b5a15 authored Jul 08, 2022 by Gao Xiang

erofs: avoid consecutive detection for Highmem memory



Currently, vmap()s are avoided if physical addresses are
consecutive for decompressed buffers.

I observed that is very common for 4KiB pclusters since the
numbers of decompressed pages are almost 2 or 3.

However, such detection doesn't work for Highmem pages on
32-bit machines, let's fix it now.

Reported-by: Liu Jinbao <liujinbao1@xiaomi.com>
Fixes: 7fc45dbc ("staging: erofs: introduce generic decompression backend")
Link: https://lore.kernel.org/r/20220708101001.21242-1-hsiangkao@linux.alibaba.com


Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

parent 2df7c4bd

fs/erofs/decompressor.c

+10 −6

Original line number	Diff line number	Diff line
		@@ -91,14 +91,18 @@ static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx,

		if (page) {
		__clear_bit(j, bounced);
		if (kaddr) {
		if (kaddr + PAGE_SIZE == page_address(page))
		kaddr += PAGE_SIZE;
		else
		kaddr = NULL;
		} else if (!i) {
		if (!PageHighMem(page)) {
		if (!i) {
		kaddr = page_address(page);
		continue;
		}
		if (kaddr &&
		kaddr + PAGE_SIZE == page_address(page)) {
		kaddr += PAGE_SIZE;
		continue;
		}
		}
		kaddr = NULL;
		continue;
		}
		kaddr = NULL;