Commit 6e4af69a authored by David Howells's avatar David Howells Committed by Linus Torvalds
Browse files

mm/readahead: make ondemand_readahead take a readahead_control 



Make ondemand_readahead() take a readahead_control struct in preparation
for making do_sync_mmap_readahead() pass down an RAC struct.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Eric Biggers <ebiggers@google.com>
Link: https://lkml.kernel.org/r/20200903140844.14194-6-willy@infradead.org


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8238287e

mm/readahead.c

+17 −12
Original line number Diff line number Diff line
@@ -431,15 +431,14 @@ static int try_context_readahead(struct address_space *mapping, 
/*

 * A minimal readahead algorithm for trivial sequential/random reads.

 */

static void ondemand_readahead(struct address_space *mapping,

		struct file_ra_state *ra, struct file *file,

		bool hit_readahead_marker, pgoff_t index,

static void ondemand_readahead(struct readahead_control *ractl,

		struct file_ra_state *ra, bool hit_readahead_marker,

		unsigned long req_size)

{

	DEFINE_READAHEAD(ractl, file, mapping, index);

	struct backing_dev_info *bdi = inode_to_bdi(mapping->host);

	struct backing_dev_info *bdi = inode_to_bdi(ractl->mapping->host);

	unsigned long max_pages = ra->ra_pages;

	unsigned long add_pages;

	unsigned long index = readahead_index(ractl);

	pgoff_t prev_index;



	/*
@@ -477,7 +476,8 @@ static void ondemand_readahead(struct address_space *mapping, 
		pgoff_t start;



		rcu_read_lock();

		start = page_cache_next_miss(mapping, index + 1, max_pages);

		start = page_cache_next_miss(ractl->mapping, index + 1,

				max_pages);

		rcu_read_unlock();



		if (!start || start - index > max_pages)
@@ -510,14 +510,15 @@ static void ondemand_readahead(struct address_space *mapping, 
	 * Query the page cache and look for the traces(cached history pages)

	 * that a sequential stream would leave behind.

	 */

	if (try_context_readahead(mapping, ra, index, req_size, max_pages))

	if (try_context_readahead(ractl->mapping, ra, index, req_size,

			max_pages))

		goto readit;



	/*

	 * standalone, small random read

	 * Read as is, and do not pollute the readahead state.

	 */

	do_page_cache_ra(&ractl, req_size, 0);

	do_page_cache_ra(ractl, req_size, 0);

	return;



initial_readahead:
@@ -543,8 +544,8 @@ static void ondemand_readahead(struct address_space *mapping, 
		}

	}



	ractl._index = ra->start;

	do_page_cache_ra(&ractl, ra->size, ra->async_size);

	ractl->_index = ra->start;

	do_page_cache_ra(ractl, ra->size, ra->async_size);

}



/**
@@ -564,6 +565,8 @@ void page_cache_sync_readahead(struct address_space *mapping, 
			       struct file_ra_state *ra, struct file *filp,

			       pgoff_t index, unsigned long req_count)

{

	DEFINE_READAHEAD(ractl, filp, mapping, index);



	/* no read-ahead */

	if (!ra->ra_pages)

		return;
@@ -578,7 +581,7 @@ void page_cache_sync_readahead(struct address_space *mapping, 
	}



	/* do read-ahead */

	ondemand_readahead(mapping, ra, filp, false, index, req_count);

	ondemand_readahead(&ractl, ra, false, req_count);

}

EXPORT_SYMBOL_GPL(page_cache_sync_readahead);
@@ -602,6 +605,8 @@ page_cache_async_readahead(struct address_space *mapping, 
			   struct page *page, pgoff_t index,

			   unsigned long req_count)

{

	DEFINE_READAHEAD(ractl, filp, mapping, index);



	/* no read-ahead */

	if (!ra->ra_pages)

		return;
@@ -624,7 +629,7 @@ page_cache_async_readahead(struct address_space *mapping, 
		return;



	/* do read-ahead */

	ondemand_readahead(mapping, ra, filp, true, index, req_count);

	ondemand_readahead(&ractl, ra, true, req_count);

}

EXPORT_SYMBOL_GPL(page_cache_async_readahead);