Hi,
On Thursday, March 02, 2006 11:58 AM Arjan van de Ven wrote:
> Why do you need to do this? It's generally bad for drivers to snoop
> data!
I understood that is bad. I am trying to make sure the data written to disk drive are identical with the data from upper layer by comparing actual data in the driver.
This is a part of debugging only not for release driver, obviously.
So, is it completely unable to get this done?
Any tricky solution?
Thank you,
> -----Original Message-----
> From: Arjan van de Ven [mailto:[email protected]]
> Sent: Thursday, March 02, 2006 11:58 AM
> To: Ju, Seokmann
> Cc: Ju, Seokmann; [email protected];
> [email protected]
> Subject: Re: Question: how to map SCSI data DMA address to
> virtual address?
>
> On Thu, 2006-03-02 at 09:53 -0700, Ju, Seokmann wrote:
> > Hi,
> >
> > In the 'scsi_cmnd' structure, there are two entries holding address
> > information for data to be transferred. One is
> 'request_buffer' and the
> > other one is 'buffer'.
> > In case of 'use_sg' is non-zero, those entries indicates
> the address of
> > the scatter-gather table.
>
> use_sg is never non-zero so that's easy
>
> >
> > Is there way to get virtual address (so that the data could
> be accessed
> > by the driver) of the actual data in the case of 'use_sg'
> is non-zero?
>
> not really; unless you mapped it. The physical address may
> already been
> translated by the iommu... at which point there is no direct
> mapping to
> kernel memory.
>
> Why do you need to do this? It's generally bad for drivers to snoop
> data!
>
>
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
