Using a pagevec lets us keep the pages and the number of pages together
which simplifies a lot of the calling conventions.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
mm/filemap.c | 82 ++++++++++++++++++++++++----------------------------
1 file changed, 38 insertions(+), 44 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 5dec04c8e16b0..9e1e2bbac8fc9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2315,22 +2315,22 @@ 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)
@@ -2338,17 +2338,17 @@ 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);
@@ -2356,9 +2356,9 @@ 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;
}
@@ -2369,9 +2369,9 @@ 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;
}
@@ -2379,17 +2379,17 @@ 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;
/*
@@ -2421,11 +2421,8 @@ 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;
@@ -2444,12 +2441,9 @@ 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.
@@ -2465,9 +2459,9 @@ 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
@@ -2481,11 +2475,11 @@ 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);
@@ -2497,9 +2491,9 @@ 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;
@@ -2511,8 +2505,8 @@ 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);
--
2.29.2
