From: Christoph Hellwig <hch@lst.de>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Magnus Karlsson <magnus.karlsson@intel.com>,
Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
Alexander Duyck <alexanderduyck@fb.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v3 2/7] dma: avoid redundant calls for sync operations
Date: Thu, 15 Feb 2024 06:08:57 +0100 [thread overview]
Message-ID: <20240215050857.GC4861@lst.de> (raw)
In-Reply-To: <3a9dd580-1977-418f-a3f3-73003dd37710@arm.com>
On Wed, Feb 14, 2024 at 05:55:23PM +0000, Robin Murphy wrote:
>> #define DMA_F_PCI_P2PDMA_SUPPORTED (1 << 0)
>> +#define DMA_F_CAN_SKIP_SYNC BIT(1)
>
> Yuck, please be consistent - either match the style of the existing code,
> or change that to BIT(0) as well.
Just don't use BIT() ever. It doesn't save any typing and creates a
totally pointless mental indirection.
> I guess this was the existing condition from dma_need_sync(), but now it's
> on a one-off slow path it might be nice to check the sync_sg_* ops as well
> for completeness, or at least comment that nobody should be implementing
> those without also implementing the sync_single_* ops.
Implementing only one and not the other doesn't make any sense. Maybe
a debug check for that is ok, but thing will break badly if they aren't
in sync anyway.
next prev parent reply other threads:[~2024-02-15 5:09 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-14 16:21 [PATCH net-next v3 0/7] dma: skip calling no-op sync ops when possible Alexander Lobakin
2024-02-14 16:21 ` [PATCH net-next v3 1/7] dma: compile-out DMA sync op calls when not used Alexander Lobakin
2024-02-14 17:20 ` Robin Murphy
2024-02-15 5:06 ` Christoph Hellwig
2024-02-19 12:53 ` Alexander Lobakin
2024-02-26 16:27 ` Robin Murphy
2024-02-14 18:09 ` Robin Murphy
2024-02-15 5:06 ` Christoph Hellwig
2024-02-14 16:21 ` [PATCH net-next v3 2/7] dma: avoid redundant calls for sync operations Alexander Lobakin
2024-02-14 17:55 ` Robin Murphy
2024-02-15 5:08 ` Christoph Hellwig [this message]
2024-02-15 11:36 ` Robin Murphy
2024-02-19 12:49 ` Alexander Lobakin
2024-02-26 15:45 ` Robin Murphy
2024-02-14 16:21 ` [PATCH net-next v3 3/7] iommu/dma: avoid expensive indirect " Alexander Lobakin
2024-02-14 17:58 ` Robin Murphy
2024-02-14 16:21 ` [PATCH net-next v3 4/7] page_pool: make sure frag API fields don't span between cachelines Alexander Lobakin
2024-02-14 16:21 ` [PATCH net-next v3 5/7] page_pool: don't use driver-set flags field directly Alexander Lobakin
2024-02-14 16:22 ` [PATCH net-next v3 6/7] page_pool: check for DMA sync shortcut earlier Alexander Lobakin
2024-02-14 16:22 ` [PATCH net-next v3 7/7] xsk: use generic DMA sync shortcut instead of a custom one Alexander Lobakin
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