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From: David Hildenbrand <david@redhat.com>
To: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	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>,
	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] iov_iter: Use __bitwise with the extraction_flags
Date: Thu, 26 Jan 2023 11:41:40 +0100	[thread overview]
Message-ID: <b8082dcd-632b-bf75-061c-143cca6fa70d@redhat.com> (raw)
In-Reply-To: <2638928.1674729230@warthog.procyon.org.uk>

On 26.01.23 11:33, David Howells wrote:

> Interestingly, things like __be32 are __bitwise.  I wonder if that actually
> makes sense or if it was just convenient so stop people doing arithmetic on
> them.  I guess doing AND/OR/XOR on them isn't a problem provided both
> arguments are appropriately byte-swapped.

I recall that __be32 and friends were one of the early users of 
__bitwise in the kernel. And the reason IIRC was exactly that: detect 
when no proper conversion was performed using static code analysis 
(Sparse). While some operations might make sense, the abuse is much more 
likely.


LGTM, thanks!

-- 
Thanks,

David / dhildenb


  reply	other threads:[~2023-01-26 10:42 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-25 21:06 [PATCH v10 0/8] iov_iter: Improve page extraction (pin or just list) David Howells
2023-01-25 21:06 ` [PATCH v10 1/8] iov_iter: Define flags to qualify page extraction David Howells
2023-01-26  9:25   ` David Hildenbrand
2023-01-26  9:49   ` David Howells
2023-01-26  9:52     ` David Hildenbrand
2023-01-26 10:33     ` [PATCH] iov_iter: Use __bitwise with the extraction_flags David Howells
2023-01-26 10:41       ` David Hildenbrand [this message]
2023-01-26 22:27       ` Al Viro
2023-01-25 21:06 ` [PATCH v10 2/8] iov_iter: Add a function to extract a page list from an iterator David Howells
2023-01-25 21:06 ` [PATCH v10 3/8] iomap: Don't get an reference on ZERO_PAGE for direct I/O block zeroing David Howells
2023-01-25 21:06 ` [PATCH v10 4/8] block: Fix bio_flagged() so that gcc can better optimise it David Howells
2023-01-25 21:06 ` [PATCH v10 5/8] block: Replace BIO_NO_PAGE_REF with BIO_PAGE_REFFED with inverted logic David Howells
2023-01-26  9:28   ` David Hildenbrand
2023-01-26  9:32   ` David Hildenbrand
2023-01-26 11:34   ` David Howells
2023-01-26 15:14     ` Christoph Hellwig
2023-01-25 21:06 ` [PATCH v10 6/8] block: Add BIO_PAGE_PINNED and associated infrastructure David Howells
2023-01-26  9:29   ` David Hildenbrand
2023-01-25 21:06 ` [PATCH v10 7/8] block: Convert bio_iov_iter_get_pages to use iov_iter_extract_pages David Howells
2023-01-25 21:06 ` [PATCH v10 8/8] block: convert bio_map_user_iov " David Howells
2023-01-26 11:36 ` [PATCH v10 2/8] iov_iter: Add a function to extract a page list from an iterator David Howells

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