Commit 33a0f5c6 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm/filemap: don't call ->readpage if IOCB_WAITQ is set 

The readpage operation can block in many (most?) filesystems, so we should
punt to a work queue instead of calling it.  This was the last caller of
lock_page_for_iocb(), so remove it.

Link: https://lkml.kernel.org/r/20210122160140.223228-9-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarKent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f32b5dd7

mm/filemap.c

+2 −12
Original line number Diff line number Diff line
@@ -2154,16 +2154,6 @@ static void shrink_readahead_size_eio(struct file_ra_state *ra) 
	ra->ra_pages /= 4;

}



static int lock_page_for_iocb(struct kiocb *iocb, struct page *page)

{

	if (iocb->ki_flags & IOCB_WAITQ)

		return lock_page_async(page, iocb->ki_waitq);

	else if (iocb->ki_flags & IOCB_NOWAIT)

		return trylock_page(page) ? 0 : -EAGAIN;

	else

		return lock_page_killable(page);

}



/*

 * filemap_get_read_batch - Get a batch of pages for read

 *
@@ -2215,7 +2205,7 @@ static struct page *filemap_read_page(struct kiocb *iocb, struct file *filp, 
	struct file_ra_state *ra = &filp->f_ra;

	int error;



	if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT)) {

	if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) {

		unlock_page(page);

		put_page(page);

		return ERR_PTR(-EAGAIN);
@@ -2236,7 +2226,7 @@ static struct page *filemap_read_page(struct kiocb *iocb, struct file *filp, 
	}



	if (!PageUptodate(page)) {

		error = lock_page_for_iocb(iocb, page);

		error = lock_page_killable(page);

		if (unlikely(error)) {

			put_page(page);

			return ERR_PTR(error);