From: Christoph Hellwig <hch@lst.de>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: "Christoph Hellwig" <hch@lst.de>, "Jens Axboe" <axboe@kernel.dk>,
"Keith Busch" <kbusch@kernel.org>,
"Sagi Grimberg" <sagi@grimberg.me>,
"Alexander Viro" <viro@zeniv.linux.org.uk>,
"Christian Brauner" <brauner@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian König" <christian.koenig@amd.com>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org,
io-uring@vger.kernel.org, linux-media@vger.kernel.org,
dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
"Nitesh Shetty" <nj.shetty@samsung.com>,
"Kanchan Joshi" <joshi.k@samsung.com>,
"Anuj Gupta" <anuj20.g@samsung.com>,
"Tushar Gohad" <tushar.gohad@intel.com>,
"William Power" <william.power@intel.com>,
"Phil Cayton" <phil.cayton@intel.com>,
"Jason Gunthorpe" <jgg@nvidia.com>
Subject: Re: [PATCH v3 04/10] block: introduce dma map backed bio type
Date: Mon, 18 May 2026 14:54:39 +0200 [thread overview]
Message-ID: <20260518125439.GB5754@lst.de> (raw)
In-Reply-To: <24833f76-2289-4859-86d1-9215b11a1258@gmail.com>
On Mon, May 18, 2026 at 11:29:54AM +0100, Pavel Begunkov wrote:
> On 5/13/26 09:19, Christoph Hellwig wrote:
>>> + if (!bio_flagged(bio_src, BIO_DMABUF_MAP)) {
>>> + bio->bi_io_vec = bio_src->bi_io_vec;
>>> + } else {
>>> + bio->dmabuf_map = bio_src->dmabuf_map;
>>> + bio_set_flag(bio, BIO_DMABUF_MAP);
>>> + }
>>
>> This is backwards, please avoid pointless negations:
>
> I can flip it, but compilers tend to prefer the true branch. E.g. this
What kind of compiler optimization do you expect from code where
both sides of the conditional assign different arms of the same union
and just propagate the bit that was set?
next prev parent reply other threads:[~2026-05-18 12:54 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-29 15:25 [PATCH v3 00/10] Add dmabuf read/write via io_uring Pavel Begunkov
2026-04-29 15:25 ` [PATCH v3 01/10] file: add callback for creating long-term dmabuf maps Pavel Begunkov
2026-04-30 6:03 ` Christian König
2026-04-30 18:33 ` Pavel Begunkov
2026-05-04 7:14 ` Christian König
2026-05-13 8:11 ` Christoph Hellwig
2026-04-29 15:25 ` [PATCH v3 02/10] iov_iter: add iterator type for " Pavel Begunkov
2026-05-13 8:11 ` Christoph Hellwig
2026-05-13 10:05 ` David Laight
2026-05-13 13:29 ` David Laight
2026-05-18 9:24 ` Pavel Begunkov
2026-05-18 10:40 ` David Laight
2026-04-29 15:25 ` [PATCH v3 03/10] block: move bvec init into __bio_clone Pavel Begunkov
2026-05-13 8:12 ` Christoph Hellwig
2026-05-18 9:10 ` Pavel Begunkov
2026-04-29 15:25 ` [PATCH v3 04/10] block: introduce dma map backed bio type Pavel Begunkov
2026-05-13 8:19 ` Christoph Hellwig
2026-05-18 10:29 ` Pavel Begunkov
2026-05-18 12:22 ` Christian König
2026-05-18 12:40 ` Pavel Begunkov
2026-05-18 12:57 ` Christoph Hellwig
2026-05-18 13:59 ` Pavel Begunkov
2026-05-18 12:54 ` Christoph Hellwig [this message]
2026-05-19 9:21 ` David Laight
2026-05-20 8:30 ` Christoph Hellwig
2026-05-25 7:29 ` Pavel Begunkov
2026-05-13 8:39 ` Christoph Hellwig
2026-05-18 9:11 ` Pavel Begunkov
2026-04-29 15:25 ` [PATCH v3 05/10] lib: add dmabuf token infrastructure Pavel Begunkov
2026-05-13 8:24 ` Christoph Hellwig
2026-05-18 10:14 ` Pavel Begunkov
2026-05-18 12:53 ` Christoph Hellwig
2026-05-18 14:23 ` Pavel Begunkov
2026-05-19 6:56 ` Christoph Hellwig
2026-05-19 7:55 ` Pavel Begunkov
2026-05-19 9:25 ` Christoph Hellwig
2026-05-18 11:24 ` Markus Elfring
2026-05-18 14:02 ` Markus Elfring
2026-04-29 15:25 ` [PATCH v3 06/10] block: forward create_dmabuf_token to drivers Pavel Begunkov
2026-05-13 8:25 ` Christoph Hellwig
2026-05-18 9:13 ` Pavel Begunkov
2026-04-29 15:25 ` [PATCH v3 07/10] nvme-pci: implement dma_token backed requests Pavel Begunkov
2026-04-29 15:29 ` Pavel Begunkov
2026-04-29 16:07 ` Maurizio Lombardi
2026-04-30 18:18 ` Pavel Begunkov
2026-05-13 8:38 ` Christoph Hellwig
2026-05-18 9:29 ` Pavel Begunkov
2026-05-18 10:18 ` Anuj Gupta/Anuj Gupta
2026-05-18 10:30 ` Pavel Begunkov
2026-04-29 15:25 ` [PATCH v3 08/10] io_uring/rsrc: introduce buf registration structure Pavel Begunkov
2026-04-29 15:25 ` [PATCH v3 09/10] io_uring/rsrc: extend buffer update Pavel Begunkov
2026-04-29 15:25 ` [PATCH v3 10/10] io_uring/rsrc: add dmabuf backed registered buffers Pavel Begunkov
2026-05-04 15:29 ` [PATCH v3 00/10] Add dmabuf read/write via io_uring Ming Lei
2026-05-06 9:02 ` Pavel Begunkov
2026-05-07 9:50 ` Ming Lei
2026-05-12 9:30 ` Pavel Begunkov
2026-05-12 7:00 ` Christoph Hellwig
2026-05-12 9:30 ` Pavel Begunkov
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