From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rajesh Shah <rajesh.shah@intel.com>
Subject: Re: [PATCH 6/25] msi: Implement helper functions read_msi_msg and write_msi_msg.
Date: Tue, 20 Jun 2006 18:04:31 -0700
Message-ID: <20060620180431.C10402@unix-os.sc.intel.com>
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In-Reply-To: <11508425201406-git-send-email-ebiederm@xmission.com>; from ebiederm@xmission.com on Tue, Jun 20, 2006 at 04:28:19PM -0600
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To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, discuss@x86-64.org, Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>, Andi Kleen <ak@suse.de>, Natalie Protasevich <Natalie.Protasevich@UNISYS.com>, Len Brown <len.brown@intel.com>, Kimball Murray <kimball.murray@gmail.com>, Brice Goglin <brice@myri.com>, Greg Lindahl <greg.lindahl@qlogic.com>, Dave Olson <olson@unixfolk.com>, Jeff Garzik <jeff@garzik.org>, Greg KH <gregkh@suse.de>, Grant Grundler <iod00d@hp.com>, "bibo,mao" <bibo.mao@intel.com>, Rajesh Shah <rajesh.shah@intel.com>, Mark Maule <maule@sgi.com>, Jesper Juhl <jesper.juhl@gmail.com>, Shaohua Li <shaohua.li@intel.com>, Matthew Wilcox <matthew@wil.cx>, "Michael S. Tsirkin" <mst@mellanox.co.il>, Ashok Raj <ashok.raj@intel.com>, Randy Dunlap <rdunlap@xenotime.net>

On Tue, Jun 20, 2006 at 04:28:19PM -0600, Eric W. Biederman wrote:
> In support of this I also add a struct msi_msg that captures
> the the two address and one data field ina typical msi message,
> and I remember the pos and if the address is 64bit in
> struct msi_desc.
> 
One thing I found very useful was to kmalloc msi_msg at MSI/MSI-X
enable time, and stick a pointer to it in the msi_desc structure,
not just for the CONFIG_PM case. For MSI, there's a single pointer
to track. This simplified a lot of code and allowed me to avoid
pci config reads to read the hardware at various places.

> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> ---
>  drivers/pci/msi.c   |  195 +++++++++++++++++++++++++--------------------------
>  drivers/pci/msi.h   |    9 +-
>  include/linux/pci.h |    6 ++
>  3 files changed, 104 insertions(+), 106 deletions(-)
> 
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index c1c93f0..e9db6c5 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -94,63 +94,100 @@ static void msi_set_mask_bit(unsigned in
>  	}
>  }
>  
> -#ifdef CONFIG_SMP
> -static void set_msi_affinity(unsigned int vector, cpumask_t cpu_mask)
> +static void read_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
>  {

You wouldn't need this if you saved away the msi_msg values
returned from ->setup().

Rajesh