Commit 58540f5c authored by Jan Kara's avatar Jan Kara Committed by Andrew Morton
Browse files

readahead: simplify gotos in page_cache_sync_ra() 

Unify all conditions for initial readahead to simplify goto logic in
page_cache_sync_ra().  No functional changes.

Link: https://lkml.kernel.org/r/20240625101909.12234-10-jack@suse.cz


Signed-off-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Tested-by: default avatarZhang Peng <zhangpengpeng0808@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent a6eccd5b

mm/readahead.c

+9 −17
Original line number Diff line number Diff line
@@ -532,20 +532,19 @@ void page_cache_sync_ra(struct readahead_control *ractl, 
	}



	max_pages = ractl_max_pages(ractl, req_count);

	prev_index = (unsigned long long)ra->prev_pos >> PAGE_SHIFT;

	/*

	 * start of file or oversized read

	 */

	if (!index || req_count > max_pages)

		goto initial_readahead;



	/*

	 * sequential cache miss

	 * A start of file, oversized read, or sequential cache miss:

	 * trivial case: (index - prev_index) == 1

	 * unaligned reads: (index - prev_index) == 0

	 */

	prev_index = (unsigned long long)ra->prev_pos >> PAGE_SHIFT;

	if (index - prev_index <= 1UL)

		goto initial_readahead;

	if (!index || req_count > max_pages || index - prev_index <= 1UL) {

		ra->start = index;

		ra->size = get_init_ra_size(req_count, max_pages);

		ra->async_size = ra->size > req_count ? ra->size - req_count :

							ra->size >> 1;

		goto readit;

	}



	/*

	 * Query the page cache and look for the traces(cached history pages)
@@ -572,13 +571,6 @@ void page_cache_sync_ra(struct readahead_control *ractl, 
	ra->start = index;

	ra->size = min(contig_count + req_count, max_pages);

	ra->async_size = 1;

	goto readit;



initial_readahead:

	ra->start = index;

	ra->size = get_init_ra_size(req_count, max_pages);

	ra->async_size = ra->size > req_count ? ra->size - req_count :

						ra->size >> 1;

readit:

	ractl->_index = ra->start;

	page_cache_ra_order(ractl, ra, 0);