Commit e4c1cf52 authored by Gao Xiang's avatar Gao Xiang
Browse files

erofs: tidy up z_erofs_do_read_page() 



 - Fix a typo: spiltted => split;

 - Move !EROFS_MAP_MAPPED and EROFS_MAP_FRAGMENT upwards;

 - Increase `split` in advance to avoid unnecessary repeats.

Reviewed-by: default avatarYue Hu <huyue2@coolpad.com>
Reviewed-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230817082813.81180-4-hsiangkao@linux.alibaba.com
parent aeebae9d

fs/erofs/zdata.c

+24 −29
Original line number Diff line number Diff line
@@ -981,49 +981,34 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, 
	struct erofs_map_blocks *const map = &fe->map;

	const loff_t offset = page_offset(page);

	bool tight = true, exclusive;

	unsigned int cur, end, len, spiltted;

	unsigned int cur, end, len, split;

	int err = 0;



	/* register locked file pages as online pages in pack */

	z_erofs_onlinepage_init(page);



	spiltted = 0;

	split = 0;

	end = PAGE_SIZE;

repeat:

	cur = end - 1;



	if (offset + cur < map->m_la ||

	    offset + cur >= map->m_la + map->m_llen) {

	if (offset + end - 1 < map->m_la ||

	    offset + end - 1 >= map->m_la + map->m_llen) {

		z_erofs_pcluster_end(fe);

		map->m_la = offset + cur;

		map->m_la = offset + end - 1;

		map->m_llen = 0;

		err = z_erofs_map_blocks_iter(inode, map, 0);

		if (err)

			goto out;

	} else if (fe->pcl) {

		goto hitted;

	}



	if ((map->m_flags & EROFS_MAP_MAPPED) &&

	    !(map->m_flags & EROFS_MAP_FRAGMENT)) {

		err = z_erofs_pcluster_begin(fe);

		if (err)

			goto out;

	}

hitted:

	/*

	 * Ensure the current partial page belongs to this submit chain rather

	 * than other concurrent submit chains or the noio(bypass) chain since

	 * those chains are handled asynchronously thus the page cannot be used

	 * for inplace I/O or bvpage (should be processed in a strict order.)

	 */

	tight &= (fe->mode > Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE);

	cur = offset > map->m_la ? 0 : map->m_la - offset;

	/* bump split parts first to avoid several separate cases */

	++split;



	cur = end - min_t(erofs_off_t, offset + end - map->m_la, end);

	if (!(map->m_flags & EROFS_MAP_MAPPED)) {

		zero_user_segment(page, cur, end);

		tight = false;

		goto next_part;

	}



	if (map->m_flags & EROFS_MAP_FRAGMENT) {

		erofs_off_t fpos = offset + cur - map->m_la;
@@ -1032,12 +1017,24 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, 
				EROFS_I(inode)->z_fragmentoff + fpos);

		if (err)

			goto out;

		++spiltted;

		tight = false;

		goto next_part;

	}



	exclusive = (!cur && (!spiltted || tight));

	if (!fe->pcl) {

		err = z_erofs_pcluster_begin(fe);

		if (err)

			goto out;

	}



	/*

	 * Ensure the current partial page belongs to this submit chain rather

	 * than other concurrent submit chains or the noio(bypass) chain since

	 * those chains are handled asynchronously thus the page cannot be used

	 * for inplace I/O or bvpage (should be processed in a strict order.)

	 */

	tight &= (fe->mode > Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE);

	exclusive = (!cur && ((split <= 1) || tight));

	if (cur)

		tight &= (fe->mode >= Z_EROFS_PCLUSTER_FOLLOWED);
@@ -1050,8 +1047,6 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, 
		goto out;



	z_erofs_onlinepage_split(page);

	/* bump up the number of spiltted parts of a page */

	++spiltted;

	if (fe->pcl->pageofs_out != (map->m_la & ~PAGE_MASK))

		fe->pcl->multibases = true;

	if (fe->pcl->length < offset + end - map->m_la) {