netdev - RE: [PATCH net-next 01/11] sfc: Implement 128-bit writes for efx_writeo

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 12 Jul 2012 09:45:05 +0100
From:	"David Laight" <David.Laight@...LAB.COM>
To:	"Ben Hutchings" <bhutchings@...arflare.com>,
	"David Miller" <davem@...emloft.net>
Cc:	<netdev@...r.kernel.org>, <linux-net-drivers@...arflare.com>
Subject: RE: [PATCH net-next 01/11] sfc: Implement 128-bit writes for efx_writeo_page

> From: netdev-owner@...r.kernel.org [mailto:netdev-
> owner@...r.kernel.org] On Behalf Of Ben Hutchings
> Sent: 12 July 2012 00:15
> To: David Miller
> Cc: netdev@...r.kernel.org; linux-net-drivers@...arflare.com
> Subject: [PATCH net-next 01/11] sfc: Implement 128-bit writes for
> efx_writeo_page
> 
> Add support for writing a TX descriptor to the NIC in one PCIe
> transaction on x86_64 machines.
...
> +static inline void _efx_writeo(struct efx_nic *efx, efx_le_128 value,
> +			       unsigned int reg)
> +{
...
> +}

Wouldn't it be better to put code this in some generic header
where it can be used by other drivers?

Some architectures/cpus have dma engines associated with the
PCIe interface than can be used to request longer PCIe transactions.

So you probably need a transfer length as well.

I suspect that it is never worth using an interrupt for
the completion of such dma - although splitting the request
and wait would allow the caller to overlap operations.

With a dma interface it is worth updating multiple ring
entries at one, and reading multiple entries for status.

	David