Messages in this thread | | | Date | Mon, 4 Apr 2016 19:47:36 +0100 | From | Al Viro <> | Subject | Re: [RFC] weird semantics of SG_DXFER_TO_FROM_DEV in BLK_DEV_SKD (drivers/block/skd*) |
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On Mon, Apr 04, 2016 at 06:16:12PM +0100, Al Viro wrote:
> will see NULL map_data; the ->from_user case is sg_start_req() stuff. IOW, > SG_IO behaviour for /dev/sg* is different from the generic one...
While we are at it: in bio_map_user_iov() we have iov_for_each(iov, i, *iter) { unsigned long uaddr = (unsigned long) iov.iov_base; unsigned long len = iov.iov_len; unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; unsigned long start = uaddr >> PAGE_SHIFT;
/* * Overflow, abort */ if (end < start) return ERR_PTR(-EINVAL);
nr_pages += end - start; /* * buffer must be aligned to at least hardsector size for now */ if (uaddr & queue_dma_alignment(q)) return ERR_PTR(-EINVAL); }
Do we only care about the iov_base alignment? IOW, shouldn't we check for iov_len being a multiple of queue_dma_alignment(q) as well?
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