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mm/filemap: change filemap_read_page calling conventions

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Make this function more generic by passing the file instead of the iocb.
Check in the callers whether we should call readpage or not.  Also make it
return an errno / 0 / AOP_TRUNCATED_PAGE, and make calling put_page() the
caller's responsibility.

Link: https://lkml.kernel.org/r/20210122160140.223228-10-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 12:02:15 -08:00 committed by Linus Torvalds
parent 33a0f5c6b3
commit 68430303c8
1 changed files with 42 additions and 47 deletions
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89
mm/filemap.c
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@ -2199,56 +2199,38 @@ static void filemap_get_read_batch(struct address_space *mapping,
rcu_read_unlock();
}
static struct page *filemap_read_page(struct kiocb *iocb, struct file *filp,
struct address_space *mapping, struct page *page)
static int filemap_read_page(struct file *file, struct address_space *mapping,
struct page *page)
{
struct file_ra_state *ra = &filp->f_ra;
int error;
if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) {
unlock_page(page);
put_page(page);
return ERR_PTR(-EAGAIN);
}
/*
* A previous I/O error may have been due to temporary
* failures, eg. multipath errors.
* PG_error will be set again if readpage fails.
* A previous I/O error may have been due to temporary failures,
* eg. multipath errors. PG_error will be set again if readpage
* fails.
*/
ClearPageError(page);
/* Start the actual read. The read will unlock the page. */
error = mapping->a_ops->readpage(filp, page);
if (unlikely(error)) {
put_page(page);
return error != AOP_TRUNCATED_PAGE ? ERR_PTR(error) : NULL;
}
error = mapping->a_ops->readpage(file, page);
if (error)
return error;
if (PageUptodate(page))
return 0;
error = lock_page_killable(page);
if (error)
return error;
if (!PageUptodate(page)) {
error = lock_page_killable(page);
if (unlikely(error)) {
put_page(page);
return ERR_PTR(error);
if (page->mapping == NULL) {
/* page truncated */
error = AOP_TRUNCATED_PAGE;
} else {
shrink_readahead_size_eio(&file->f_ra);
error = -EIO;
}
if (!PageUptodate(page)) {
if (page->mapping == NULL) {
/*
* invalidate_mapping_pages got it
*/
unlock_page(page);
put_page(page);
return NULL;
}
unlock_page(page);
shrink_readahead_size_eio(ra);
put_page(page);
return ERR_PTR(-EIO);
}
unlock_page(page);
}
return page;
unlock_page(page);
return error;
}
static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp,
@ -2290,7 +2272,18 @@ static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp,
return page;
readpage:
return filemap_read_page(iocb, filp, mapping, page);
if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) {
unlock_page(page);
put_page(page);
return ERR_PTR(-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);
truncated:
unlock_page(page);
put_page(page);
@ -2306,7 +2299,7 @@ static struct page *filemap_create_page(struct kiocb *iocb,
struct page *page;
int error;
if (iocb->ki_flags & IOCB_NOIO)
if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ))
return ERR_PTR(-EAGAIN);
page = page_cache_alloc(mapping);
@ -2315,12 +2308,14 @@ static struct page *filemap_create_page(struct kiocb *iocb,
error = add_to_page_cache_lru(page, mapping, index,
mapping_gfp_constraint(mapping, GFP_KERNEL));
if (error) {
put_page(page);
return error != -EEXIST ? ERR_PTR(error) : NULL;
}
return filemap_read_page(iocb, filp, mapping, page);
if (!error)
error = filemap_read_page(iocb->ki_filp, mapping, page);
if (!error)
return page;
put_page(page);
if (error == -EEXIST || error == AOP_TRUNCATED_PAGE)
return NULL;
return ERR_PTR(error);
}
static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,