On Thu, Mar 02 2006, linux-os (Dick Johnson) wrote: > > On Thu, 2 Mar 2006, 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. > > > > 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? > > > > Any comments would be appreciated. > > > > > > Thank you, > > > > Seokmann > > - > > There is a macro for this purpose. However, for experiments, in > the kernel, you can add PAGE_OFFSET (0xC00000000) to get the virtual > address. The macro is __va(a), its inverse is __pa(a). > > Careful. These things can change. Bzzt no, this wont work if an iommu is involved. It also wont work if the page doesn't have a virtual address mapping (think highmem). -- Jens Axboe - : 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
