Commit ff993ba1 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm/filemap: convert filemap_get_pages to take a pagevec 

Using a pagevec lets us keep the pages and the number of pages together
which simplifies a lot of the calling conventions.

Link: https://lkml.kernel.org/r/20210122160140.223228-4-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0c7c575d

mm/filemap.c

+38 −44
Original line number Diff line number Diff line
@@ -2325,22 +2325,22 @@ static struct page *filemap_create_page(struct kiocb *iocb, 
}



static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,

		struct page **pages, unsigned int nr)

		struct pagevec *pvec)

{

	struct file *filp = iocb->ki_filp;

	struct address_space *mapping = filp->f_mapping;

	struct file_ra_state *ra = &filp->f_ra;

	pgoff_t index = iocb->ki_pos >> PAGE_SHIFT;

	pgoff_t last_index = (iocb->ki_pos + iter->count + PAGE_SIZE-1) >> PAGE_SHIFT;

	int i, j, nr_got, err = 0;

	unsigned int nr = min_t(unsigned long, last_index - index, PAGEVEC_SIZE);

	int i, j, err = 0;



	nr = min_t(unsigned long, last_index - index, nr);

find_page:

	if (fatal_signal_pending(current))

		return -EINTR;



	nr_got = find_get_pages_contig(mapping, index, nr, pages);

	if (nr_got)

	pvec->nr = find_get_pages_contig(mapping, index, nr, pvec->pages);

	if (pvec->nr)

		goto got_pages;



	if (iocb->ki_flags & IOCB_NOIO)
@@ -2348,17 +2348,17 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 


	page_cache_sync_readahead(mapping, ra, filp, index, last_index - index);



	nr_got = find_get_pages_contig(mapping, index, nr, pages);

	if (nr_got)

	pvec->nr = find_get_pages_contig(mapping, index, nr, pvec->pages);

	if (pvec->nr)

		goto got_pages;



	pages[0] = filemap_create_page(iocb, iter);

	err = PTR_ERR_OR_ZERO(pages[0]);

	if (!IS_ERR_OR_NULL(pages[0]))

		nr_got = 1;

	pvec->pages[0] = filemap_create_page(iocb, iter);

	err = PTR_ERR_OR_ZERO(pvec->pages[0]);

	if (!IS_ERR_OR_NULL(pvec->pages[0]))

		pvec->nr = 1;

got_pages:

	for (i = 0; i < nr_got; i++) {

		struct page *page = pages[i];

	for (i = 0; i < pvec->nr; i++) {

		struct page *page = pvec->pages[i];

		pgoff_t pg_index = index + i;

		loff_t pg_pos = max(iocb->ki_pos,

				    (loff_t) pg_index << PAGE_SHIFT);
@@ -2366,9 +2366,9 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 


		if (PageReadahead(page)) {

			if (iocb->ki_flags & IOCB_NOIO) {

				for (j = i; j < nr_got; j++)

					put_page(pages[j]);

				nr_got = i;

				for (j = i; j < pvec->nr; j++)

					put_page(pvec->pages[j]);

				pvec->nr = i;

				err = -EAGAIN;

				break;

			}
@@ -2379,9 +2379,9 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 
		if (!PageUptodate(page)) {

			if ((iocb->ki_flags & IOCB_NOWAIT) ||

			    ((iocb->ki_flags & IOCB_WAITQ) && i)) {

				for (j = i; j < nr_got; j++)

					put_page(pages[j]);

				nr_got = i;

				for (j = i; j < pvec->nr; j++)

					put_page(pvec->pages[j]);

				pvec->nr = i;

				err = -EAGAIN;

				break;

			}
@@ -2389,17 +2389,17 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 
			page = filemap_update_page(iocb, filp, iter, page,

					pg_pos, pg_count);

			if (IS_ERR_OR_NULL(page)) {

				for (j = i + 1; j < nr_got; j++)

					put_page(pages[j]);

				nr_got = i;

				for (j = i + 1; j < pvec->nr; j++)

					put_page(pvec->pages[j]);

				pvec->nr = i;

				err = PTR_ERR_OR_ZERO(page);

				break;

			}

		}

	}



	if (likely(nr_got))

		return nr_got;

	if (likely(pvec->nr))

		return 0;

	if (err)

		return err;

	/*
@@ -2431,11 +2431,8 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, 
	struct file_ra_state *ra = &filp->f_ra;

	struct address_space *mapping = filp->f_mapping;

	struct inode *inode = mapping->host;

	struct page *pages[PAGEVEC_SIZE];

	unsigned int nr_pages = min_t(unsigned int, PAGEVEC_SIZE,

			((iocb->ki_pos + iter->count + PAGE_SIZE - 1) >> PAGE_SHIFT) -

			(iocb->ki_pos >> PAGE_SHIFT));

	int i, pg_nr, error = 0;

	struct pagevec pvec;

	int i, error = 0;

	bool writably_mapped;

	loff_t isize, end_offset;
@@ -2457,12 +2454,9 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, 
		if ((iocb->ki_flags & IOCB_WAITQ) && written)

			iocb->ki_flags |= IOCB_NOWAIT;



		i = 0;

		pg_nr = filemap_get_pages(iocb, iter, pages, nr_pages);

		if (pg_nr < 0) {

			error = pg_nr;

		error = filemap_get_pages(iocb, iter, &pvec);

		if (error < 0)

			break;

		}



		/*

		 * i_size must be checked after we know the pages are Uptodate.
@@ -2478,9 +2472,9 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, 


		end_offset = min_t(loff_t, isize, iocb->ki_pos + iter->count);



		while ((iocb->ki_pos >> PAGE_SHIFT) + pg_nr >

		while ((iocb->ki_pos >> PAGE_SHIFT) + pvec.nr >

		       (end_offset + PAGE_SIZE - 1) >> PAGE_SHIFT)

			put_page(pages[--pg_nr]);

			put_page(pvec.pages[--pvec.nr]);



		/*

		 * Once we start copying data, we don't want to be touching any
@@ -2494,11 +2488,11 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, 
		 */

		if (iocb->ki_pos >> PAGE_SHIFT !=

		    ra->prev_pos >> PAGE_SHIFT)

			mark_page_accessed(pages[0]);

		for (i = 1; i < pg_nr; i++)

			mark_page_accessed(pages[i]);

			mark_page_accessed(pvec.pages[0]);

		for (i = 1; i < pagevec_count(&pvec); i++)

			mark_page_accessed(pvec.pages[i]);



		for (i = 0; i < pg_nr; i++) {

		for (i = 0; i < pagevec_count(&pvec); i++) {

			unsigned int offset = iocb->ki_pos & ~PAGE_MASK;

			unsigned int bytes = min_t(loff_t, end_offset - iocb->ki_pos,

						   PAGE_SIZE - offset);
@@ -2510,9 +2504,9 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, 
			 * before reading the page on the kernel side.

			 */

			if (writably_mapped)

				flush_dcache_page(pages[i]);

				flush_dcache_page(pvec.pages[i]);



			copied = copy_page_to_iter(pages[i], offset, bytes, iter);

			copied = copy_page_to_iter(pvec.pages[i], offset, bytes, iter);



			written += copied;

			iocb->ki_pos += copied;
@@ -2524,8 +2518,8 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, 
			}

		}

put_pages:

		for (i = 0; i < pg_nr; i++)

			put_page(pages[i]);

		for (i = 0; i < pagevec_count(&pvec); i++)

			put_page(pvec.pages[i]);

	} while (iov_iter_count(iter) && iocb->ki_pos < isize && !error);



	file_accessed(filp);