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From: David Miller <davem@davemloft.net>
To: vadym.kochan@plvision.eu
Cc: kuba@kernel.org, jiri@mellanox.com, idosch@mellanox.com,
	andrew@lunn.ch, oleksandr.mazur@plvision.eu,
	serhiy.boiko@plvision.eu, serhiy.pshyk@plvision.eu,
	volodymyr.mytnyk@plvision.eu, taras.chornyi@plvision.eu,
	andrii.savka@plvision.eu, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, andy.shevchenko@gmail.com,
	mickeyr@marvell.com
Subject: Re: [net-next v5 1/6] net: marvell: prestera: Add driver for Prestera family ASIC devices
Date: Tue, 25 Aug 2020 17:20:03 -0700 (PDT)	[thread overview]
Message-ID: <20200825.172003.1417643181819895272.davem@davemloft.net> (raw)
In-Reply-To: <20200825122013.2844-2-vadym.kochan@plvision.eu>

From: Vadym Kochan <vadym.kochan@plvision.eu>
Date: Tue, 25 Aug 2020 15:20:08 +0300

> +int prestera_dsa_parse(struct prestera_dsa *dsa, const u8 *dsa_buf)
> +{
> +	__be32 *dsa_words = (__be32 *)dsa_buf;
> +	enum prestera_dsa_cmd cmd;
> +	u32 words[4] = { 0 };
> +	u32 field;
> +
> +	words[0] = ntohl(dsa_words[0]);
> +	words[1] = ntohl(dsa_words[1]);
> +	words[2] = ntohl(dsa_words[2]);
> +	words[3] = ntohl(dsa_words[3]);

All 4 elements of words[] are explicitly and unconditionally set to something,
so you don't need the "= { 0 }" initializer.

> +	INIT_LIST_HEAD(&sw->port_list);

What locking protects this list?

> +	new_skb = alloc_skb(len, GFP_ATOMIC | GFP_DMA);
> +	if (!new_skb)
> +		goto err_alloc_skb;

This seems very costly to do copies on every packet.  There should be
something in the dma_*() API that would allow you to avoid this.

And since you just need the buffer to DMA map it into the device,
allocating an entire SKB object is overkill.  You can instead just
allocate a ring of TX bounce buffers once, and then you just copy
each packet there.  No allocations per packet.

  reply	other threads:[~2020-08-26  0:20 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-25 12:20 [net-next v5 0/6] net: marvell: prestera: Add Switchdev driver for Prestera family ASIC device 98DX326x (AC3x) Vadym Kochan
2020-08-25 12:20 ` [net-next v5 1/6] net: marvell: prestera: Add driver for Prestera family ASIC devices Vadym Kochan
2020-08-26  0:20   ` David Miller [this message]
2020-08-26  8:17     ` Vadym Kochan
2020-08-26 13:04       ` Andrew Lunn
2020-08-26 14:34       ` David Miller
2020-08-30  7:49         ` Vadym Kochan
2020-08-25 12:20 ` [net-next v5 2/6] net: marvell: prestera: Add PCI interface support Vadym Kochan
2020-08-25 12:20 ` [net-next v5 3/6] net: marvell: prestera: Add basic devlink support Vadym Kochan
2020-08-25 12:20 ` [net-next v5 4/6] net: marvell: prestera: Add ethtool interface support Vadym Kochan
2020-08-25 12:20 ` [net-next v5 5/6] net: marvell: prestera: Add Switchdev driver implementation Vadym Kochan
2020-08-25 12:20 ` [net-next v5 6/6] dt-bindings: marvell,prestera: Add description for device-tree bindings Vadym Kochan
2020-08-26  4:30 ` [net-next v5 0/6] net: marvell: prestera: Add Switchdev driver for Prestera family ASIC device 98DX326x (AC3x) Chris Packham
2020-08-30  8:00   ` Vadym Kochan

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