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:arjan@xxxxxxxxxxxxx] > Sent: Thursday, March 02, 2006 11:58 AM > To: Ju, Seokmann > Cc: Ju, Seokmann; linux-kernel@xxxxxxxxxxxxxxx; > linux-scsi@xxxxxxxxxxxxxxx > 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! > > - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
