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mm/filemap: convert filemap_update_page to return an errno 

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looked up is no longer valid.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.

Link: https://lkml.kernel.org/r/20210122160140.223228-12-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2021-02-24 12:02:22 -08:00 committed by Linus Torvalds
parent f253e1854c
commit 4612aeef09
1 changed files with 17 additions and 21 deletions
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38
mm/filemap.c
View File

@ -2233,24 +2233,21 @@ 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;
}
}
@ -2269,25 +2266,21 @@ 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,
@ -2381,11 +2374,12 @@ 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);
}
}
}
@ -2393,6 +2387,8 @@ 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;
/*