Messages in this thread |  | | Date | Mon, 09 Sep 2002 11:08:33 -0700 | From | Andrew Morton <> | Subject | Re: Calculating kernel logical address .. |
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Imran Badr wrote: > > The virt_to_bus() macro would work only for kernel logical addresses. I am > trying to find a portable way to figure out the kernel logical address of a > user buffer so that I could use virt_to_bus() for DMA. The user address is > mmap'ed from kmalloc'ed buffer in the mmap() entry of my driver. Now when > the user wants to send this data to the PCI device, it makes an ioctl call > and give the user address to the driver. Now driver has to figure out the > kernel logical address for DMA. >
You can obtain this info by walking the user's pagetables with get_user_pages(). That give `struct page' pointers, with which all things are possible. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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