On 10/03/2017 06:25 AM, Jan Kara wrote: > On Tue 03-10-17 14:10:49, Jan Kara wrote: >> On Wed 27-09-17 14:13:49, Jens Axboe wrote: >>> We currently it it for find_or_create_page(), which means that it >>> cannot fail. Ensure we also pass in 'retry == true' to >>> alloc_page_buffers(), which also ensure that it cannot fail. >>> >>> After this, there are no failure cases in grow_dev_page() that >>> occur because of a failed memory allocation. >>> >>> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> >> >> Makes sense. You can add: >> >> Reviewed-by: Jan Kara <jack@xxxxxxx> > > I forgot one question though: > >>> page = find_or_create_page(inode->i_mapping, index, gfp_mask); >>> - if (!page) >>> - return ret; > > Are we sure find_or_create_page() cannot fail for other reasons than > ENOMEM? Currently it seems to be the case AFAICT but it isn't obvious to me > that is guaranteed in future as well... It looks up a page, or allocates and adds one. If we tell the allocator that we cannot tolerate failure, then I don't see what else would be able to make it fail. That function is such an integral part of lookup/create for the page cache. -- Jens Axboe
