Date:   Thu, 26 Jan 2023 21:54:16 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     David Howells <dhowells@redhat.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Matthew Wilcox <willy@infradead.org>,
        Jens Axboe <axboe@kernel.dk>, Jan Kara <jack@suse.cz>,
        Jeff Layton <jlayton@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Christoph Hellwig <hch@lst.de>,
        John Hubbard <jhubbard@nvidia.com>
Subject: Re: [PATCH v11 1/8] iov_iter: Define flags to qualify page
 extraction.
Message-ID: <Y9L2iFZlC4CFwN4t@ZenIV>
References: <20230126141626.2809643-1-dhowells@redhat.com>
 <20230126141626.2809643-2-dhowells@redhat.com>
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On Thu, Jan 26, 2023 at 02:16:19PM +0000, David Howells wrote:

> +typedef unsigned int iov_iter_extraction_t;

> +/* Flags for iov_iter_get/extract_pages*() */
> +/* Allow P2PDMA on the extracted pages */
> +#define ITER_ALLOW_P2PDMA	((__force iov_iter_extraction_t)0x01)

That __force makes sense only if you make it a bitwise type -
otherwise it's meaningless.  IOW, either turn the typedef into

typedef unsigned int __bitwise iov_iter_extraction_t;

or lose __force in the cast...