[PATCH 5.10 164/199] cachefiles: Drop superfluous readpages aops NULL check

Greg Kroah-Hartman
2021-01-26T09:57:32Z

From: Takashi Iwai <tiwai@suse.de>

commit db58465f1121086b524be80be39d1fedbe5387f3 upstream.

After the recent actions to convert readpages aops to readahead, the
NULL checks of readpages aops in cachefiles_read_or_alloc_page() may
hit falsely. More badly, it's an ASSERT() call, and this panics.

Drop the superfluous NULL checks for fixing this regression.

[DH: Note that cachefiles never actually used readpages, so this check was
never actually necessary]

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=208883
BugLink: https://bugzilla.opensuse.org/show_bug.cgi?id=1175245
Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/cachefiles/rdwr.c | 2 --
1 file changed, 2 deletions(-)

--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -413,7 +413,6 @@ int cachefiles_read_or_alloc_page(struct

inode = d_backing_inode(object->backer);
ASSERT(S_ISREG(inode->i_mode));
- ASSERT(inode->i_mapping->a_ops->readpages);

/* calculate the shift required to use bmap */
shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
@@ -713,7 +712,6 @@ int cachefiles_read_or_alloc_pages(struc

inode = d_backing_inode(object->backer);
ASSERT(S_ISREG(inode->i_mode));
- ASSERT(inode->i_mapping->a_ops->readpages);

/* calculate the shift required to use bmap */
shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;