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Date: Mon, 19 Feb 2024 13:49:10 +0100
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Subject: Re: [PATCH net-next v3 2/7] dma: avoid redundant calls for sync
 operations
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To: Robin Murphy <robin.murphy@arm.com>
CC: "David S. Miller" <davem@davemloft.net>, Eric Dumazet
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 J. Wysocki" <rafael@kernel.org>, Magnus Karlsson <magnus.karlsson@intel.com>,
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References: <20240214162201.4168778-1-aleksander.lobakin@intel.com>
 <20240214162201.4168778-3-aleksander.lobakin@intel.com>
 <3a9dd580-1977-418f-a3f3-73003dd37710@arm.com>
From: Alexander Lobakin <aleksander.lobakin@intel.com>
In-Reply-To: <3a9dd580-1977-418f-a3f3-73003dd37710@arm.com>
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From: Robin Murphy <robin.murphy@arm.com>
Date: Wed, 14 Feb 2024 17:55:23 +0000

> On 2024-02-14 4:21 pm, Alexander Lobakin wrote:

[...]

>> +        /*
>> +         * Synchronization is not possible when none of DMA sync ops
>> +         * is set. This check precedes the below one as it disables
>> +         * the synchronization unconditionally.
>> +         */
>> +        dev->dma_skip_sync = true;
>> +    else if (ops->flags & DMA_F_CAN_SKIP_SYNC)
> 
> Personally I'd combine this into the dma-direct condition.

Please read the code comment a couple lines above :D

> 
>> +        /*
>> +         * Assume that when ``DMA_F_CAN_SKIP_SYNC`` is advertised,
>> +         * the conditions for synchronizing are the same as with
>> +         * the direct DMA.
>> +         */
>> +        dev->dma_skip_sync = dev_is_dma_coherent(dev);
>> +    else
>> +        dev->dma_skip_sync = false;
>> +}
>> +#endif /* CONFIG_DMA_NEED_SYNC */

[...]

Thanks,
Olek