Commit 4bdcd1dd authored by Jens Axboe's avatar Jens Axboe
Browse files

mm: move filemap_range_needs_writeback() into header 



No functional changes in this patch, just in preparation for efficiently
calling this light function from the block O_DIRECT handling.

Reviewed-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a08ed9aa

fs/iomap/direct-io.c

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <linux/module.h>

#include <linux/compiler.h>

#include <linux/fs.h>

#include <linux/pagemap.h>

#include <linux/iomap.h>

#include <linux/backing-dev.h>

#include <linux/uio.h>

include/linux/fs.h

+0 −2
Original line number Diff line number Diff line
@@ -2847,8 +2847,6 @@ static inline int filemap_fdatawait(struct address_space *mapping) 


extern bool filemap_range_has_page(struct address_space *, loff_t lstart,

				  loff_t lend);

extern bool filemap_range_needs_writeback(struct address_space *,

					  loff_t lstart, loff_t lend);

extern int filemap_write_and_wait_range(struct address_space *mapping,

				        loff_t lstart, loff_t lend);

extern int __filemap_fdatawrite_range(struct address_space *mapping,

include/linux/pagemap.h

+29 −0
Original line number Diff line number Diff line
@@ -963,6 +963,35 @@ static inline int add_to_page_cache(struct page *page, 
int __filemap_add_folio(struct address_space *mapping, struct folio *folio,

		pgoff_t index, gfp_t gfp, void **shadowp);



bool filemap_range_has_writeback(struct address_space *mapping,

				 loff_t start_byte, loff_t end_byte);



/**

 * filemap_range_needs_writeback - check if range potentially needs writeback

 * @mapping:           address space within which to check

 * @start_byte:        offset in bytes where the range starts

 * @end_byte:          offset in bytes where the range ends (inclusive)

 *

 * Find at least one page in the range supplied, usually used to check if

 * direct writing in this range will trigger a writeback. Used by O_DIRECT

 * read/write with IOCB_NOWAIT, to see if the caller needs to do

 * filemap_write_and_wait_range() before proceeding.

 *

 * Return: %true if the caller should do filemap_write_and_wait_range() before

 * doing O_DIRECT to a page in this range, %false otherwise.

 */

static inline bool filemap_range_needs_writeback(struct address_space *mapping,

						 loff_t start_byte,

						 loff_t end_byte)

{

	if (!mapping->nrpages)

		return false;

	if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&

	    !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))

		return false;

	return filemap_range_has_writeback(mapping, start_byte, end_byte);

}



/**

 * struct readahead_control - Describes a readahead request.

 *

mm/filemap.c

+3 −29
Original line number Diff line number Diff line
@@ -646,7 +646,7 @@ static bool mapping_needs_writeback(struct address_space *mapping) 
	return mapping->nrpages;

}



static bool filemap_range_has_writeback(struct address_space *mapping,

bool filemap_range_has_writeback(struct address_space *mapping,

				 loff_t start_byte, loff_t end_byte)

{

	XA_STATE(xas, &mapping->i_pages, start_byte >> PAGE_SHIFT);
@@ -667,34 +667,8 @@ static bool filemap_range_has_writeback(struct address_space *mapping, 
	}

	rcu_read_unlock();

	return page != NULL;



}



/**

 * filemap_range_needs_writeback - check if range potentially needs writeback

 * @mapping:           address space within which to check

 * @start_byte:        offset in bytes where the range starts

 * @end_byte:          offset in bytes where the range ends (inclusive)

 *

 * Find at least one page in the range supplied, usually used to check if

 * direct writing in this range will trigger a writeback. Used by O_DIRECT

 * read/write with IOCB_NOWAIT, to see if the caller needs to do

 * filemap_write_and_wait_range() before proceeding.

 *

 * Return: %true if the caller should do filemap_write_and_wait_range() before

 * doing O_DIRECT to a page in this range, %false otherwise.

 */

bool filemap_range_needs_writeback(struct address_space *mapping,

				   loff_t start_byte, loff_t end_byte)

{

	if (!mapping_needs_writeback(mapping))

		return false;

	if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&

	    !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))

		return false;

	return filemap_range_has_writeback(mapping, start_byte, end_byte);

}

EXPORT_SYMBOL_GPL(filemap_range_needs_writeback);

EXPORT_SYMBOL_GPL(filemap_range_has_writeback);



/**

 * filemap_write_and_wait_range - write out & wait on a file range