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From: David Miller <davem@davemloft.net>
To: snelson@pensando.io
Cc: netdev@vger.kernel.org, neel@pensando.io
Subject: Re: [PATCH net-next 1/5] ionic: clean up page handling code
Date: Mon, 31 Aug 2020 17:14:54 -0700 (PDT) [thread overview]
Message-ID: <20200831.171454.2235150331629306394.davem@davemloft.net> (raw)
In-Reply-To: <20200831233558.71417-2-snelson@pensando.io>
From: Shannon Nelson <snelson@pensando.io>
Date: Mon, 31 Aug 2020 16:35:54 -0700
> @@ -100,6 +100,8 @@ static struct sk_buff *ionic_rx_frags(struct ionic_queue *q,
> frag_len = min(len, (u16)PAGE_SIZE);
> len -= frag_len;
>
> + dma_sync_single_for_cpu(dev, dma_unmap_addr(page_info, dma_addr),
> + len, DMA_FROM_DEVICE);
> dma_unmap_page(dev, dma_unmap_addr(page_info, dma_addr),
> PAGE_SIZE, DMA_FROM_DEVICE);
> skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
The unmap operation performs a sync, if necessary, for you.
That's the pattern of usage:
map();
device read/write memory
unmap();
That's it, no more, no less.
The time to use sync is when you want to maintain the mapping and keep
using it.
next prev parent reply other threads:[~2020-09-01 0:15 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-31 23:35 [PATCH net-next 0/5] ionic: struct cleanups Shannon Nelson
2020-08-31 23:35 ` [PATCH net-next 1/5] ionic: clean up page handling code Shannon Nelson
2020-09-01 0:14 ` David Miller [this message]
2020-09-01 4:19 ` Shannon Nelson
2020-08-31 23:35 ` [PATCH net-next 2/5] ionic: smaller coalesce default Shannon Nelson
2020-08-31 23:50 ` Jakub Kicinski
2020-09-01 0:16 ` David Miller
2020-09-01 4:20 ` Shannon Nelson
2020-08-31 23:35 ` [PATCH net-next 3/5] ionic: struct reorder for faster access Shannon Nelson
2020-08-31 23:35 ` [PATCH net-next 4/5] ionic: clean up desc_info and cq_info structs Shannon Nelson
2020-08-31 23:35 ` [PATCH net-next 5/5] ionic: clean adminq service routine Shannon Nelson
2020-09-01 0:47 ` [PATCH net-next 0/5] ionic: struct cleanups Florian Fainelli
2020-09-01 4:21 ` Shannon Nelson
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