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shmem: convert shmem_file_read_iter() to use shmem_get_folio()

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Use a folio throughout, saving five calls to compound_head().

Link: https://lkml.kernel.org/r/20220902194653.1739778-28-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-09-02 20:46:23 +01:00 committed by Andrew Morton
parent eff1f906c2
commit 4601e2fc8b
1 changed files with 11 additions and 9 deletions
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20
mm/shmem.c
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@ -2577,6 +2577,7 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
offset = *ppos & ~PAGE_MASK;
for (;;) {
struct folio *folio = NULL;
struct page *page = NULL;
pgoff_t end_index;
unsigned long nr, ret;
@ -2591,17 +2592,18 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
break;
}
error = shmem_getpage(inode, index, &page, SGP_READ);
error = shmem_get_folio(inode, index, &folio, SGP_READ);
if (error) {
if (error == -EINVAL)
error = 0;
break;
}
if (page) {
unlock_page(page);
if (folio) {
folio_unlock(folio);
page = folio_file_page(folio, index);
if (PageHWPoison(page)) {
put_page(page);
folio_put(folio);
error = -EIO;
break;
}
@ -2617,14 +2619,14 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
if (index == end_index) {
nr = i_size & ~PAGE_MASK;
if (nr <= offset) {
if (page)
put_page(page);
if (folio)
folio_put(folio);
break;
}
}
nr -= offset;
if (page) {
if (folio) {
/*
* If users can be writing to this page using arbitrary
* virtual addresses, take care about potential aliasing
@ -2636,13 +2638,13 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
* Mark the page accessed if we read the beginning.
*/
if (!offset)
mark_page_accessed(page);
folio_mark_accessed(folio);
/*
* Ok, we have the page, and it's up-to-date, so
* now we can copy it to user space...
*/
ret = copy_page_to_iter(page, offset, nr, to);
put_page(page);
folio_put(folio);
} else if (user_backed_iter(to)) {
/*