> +static int filemap_read_page(struct file *file, struct address_space *mapping,
> + struct page *page)
I still think we should drop the mapping argument as well.
> + 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;
I think a goto error for the error cases would be much more useful.
That would allow to also share the error put_page for the flag check
above and the truncated case below, but most importantly make the code
flow obvious vs the early return for the success case.
> - 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);
Same here.
