From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Kent Overstreet <kent.overstreet@gmail.com>,
Christoph Hellwig <hch@lst.de>
Subject: [PATCH v5 11/18] mm/filemap: Convert filemap_update_page to return an errno
Date: Fri, 22 Jan 2021 16:01:33 +0000 [thread overview]
Message-ID: <20210122160140.223228-12-willy@infradead.org> (raw)
In-Reply-To: <20210122160140.223228-1-willy@infradead.org>
Use AOP_TRUNCATED_PAGE to indicate that no error occurred, but the
page we looked up is no longer valid. In this case, the reference
to the page will have been removed; if we hit any other error, the
caller will release the reference.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
mm/filemap.c | 38 +++++++++++++++++---------------------
1 file changed, 17 insertions(+), 21 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 3e0790626addf..469fc97659cb5 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2246,24 +2246,21 @@ static int filemap_read_page(struct file *file, struct address_space *mapping,
return error;
}
-static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp,
- struct iov_iter *iter, struct page *page, loff_t pos,
- loff_t count)
+static int filemap_update_page(struct kiocb *iocb,
+ struct address_space *mapping, struct iov_iter *iter,
+ struct page *page, loff_t pos, loff_t count)
{
- struct address_space *mapping = filp->f_mapping;
struct inode *inode = mapping->host;
int error;
if (iocb->ki_flags & IOCB_WAITQ) {
error = lock_page_async(page, iocb->ki_waitq);
- if (error) {
- put_page(page);
- return ERR_PTR(error);
- }
+ if (error)
+ return error;
} else {
if (!trylock_page(page)) {
put_and_wait_on_page_locked(page, TASK_KILLABLE);
- return NULL;
+ return AOP_TRUNCATED_PAGE;
}
}
@@ -2282,25 +2279,21 @@ static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp,
goto readpage;
uptodate:
unlock_page(page);
- return page;
+ return 0;
readpage:
if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) {
unlock_page(page);
- put_page(page);
- return ERR_PTR(-EAGAIN);
+ return -EAGAIN;
}
error = filemap_read_page(iocb->ki_filp, mapping, page);
- if (!error)
- return page;
- put_page(page);
if (error == AOP_TRUNCATED_PAGE)
- return NULL;
- return ERR_PTR(error);
+ put_page(page);
+ return error;
truncated:
unlock_page(page);
put_page(page);
- return NULL;
+ return AOP_TRUNCATED_PAGE;
}
static int filemap_create_page(struct file *file,
@@ -2394,11 +2387,12 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
goto err;
}
- page = filemap_update_page(iocb, filp, iter, page,
+ err = filemap_update_page(iocb, mapping, iter, page,
pg_pos, pg_count);
- if (IS_ERR_OR_NULL(page)) {
+ if (err) {
+ if (err < 0)
+ put_page(page);
pvec->nr--;
- err = PTR_ERR_OR_ZERO(page);
}
}
}
@@ -2406,6 +2400,8 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
err:
if (likely(pvec->nr))
return 0;
+ if (err == AOP_TRUNCATED_PAGE)
+ goto find_page;
if (err)
return err;
/*
--
2.29.2
next prev parent reply other threads:[~2021-01-22 16:12 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 16:01 [PATCH v5 00/18] Refactor generic_file_buffered_read Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 01/18] mm/filemap: Rename generic_file_buffered_read subfunctions Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 02/18] mm/filemap: Remove dynamically allocated array from filemap_read Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 03/18] mm/filemap: Convert filemap_get_pages to take a pagevec Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 04/18] mm/filemap: Use head pages in generic_file_buffered_read Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 05/18] mm/filemap: Pass a sleep state to put_and_wait_on_page_locked Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 06/18] mm/filemap: Support readpage splitting a page Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 07/18] mm/filemap: Inline __wait_on_page_locked_async into caller Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 08/18] mm/filemap: Don't call ->readpage if IOCB_WAITQ is set Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 09/18] mm/filemap: Change filemap_read_page calling conventions Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 10/18] mm/filemap: Change filemap_create_page " Matthew Wilcox (Oracle)
2021-01-22 16:01 ` Matthew Wilcox (Oracle) [this message]
2021-01-22 16:01 ` [PATCH v5 12/18] mm/filemap: Move the iocb checks into filemap_update_page Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 13/18] mm/filemap: Add filemap_range_uptodate Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 14/18] mm/filemap: Split filemap_readahead out of filemap_get_pages Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 15/18] mm/filemap: Restructure filemap_get_pages Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 16/18] mm/filemap: Don't relock the page after calling readpage Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 17/18] mm/filemap: Rename generic_file_buffered_read to filemap_read Matthew Wilcox (Oracle)
2021-01-22 16:01 ` [PATCH v5 18/18] mm/filemap: Simplify generic_file_read_iter Matthew Wilcox (Oracle)
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