Implement vs{,un}lock_device and use it for physio.

Just like normal vs{,un}lock, but in case the pages we get are not dma
accessible, we bounce them, if they are dma acessible, the functions behave
exactly like normal vslock. The plan for the future is to have fault_wire
allocate dma acessible pages so that we don't need to bounce (especially
in cases where the same buffer is reused for physio over and over again),
but for now, keep it as simple as possible.

1 files changed, 14 insertions, 7 deletions

diff --git a/sys/kern/kern_physio.c b/sys/kern/kern_physio.c
index 0dae0225874..546b18fd27e 100644
--- a/sys/kern/kern_physio.c
+++ b/sys/kern/kern_physio.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_physio.c,v 1.30 2010/06/23 14:18:32 thib Exp $	*/
+/*	$OpenBSD: kern_physio.c,v 1.31 2010/07/01 21:27:39 art Exp $	*/
 /*	$NetBSD: kern_physio.c,v 1.28 1997/05/19 10:43:28 pk Exp $	*/
 
 /*-
@@ -113,6 +113,8 @@ physio(void (*strategy)(struct buf *), struct buf *bp, dev_t dev, int flags,
 	for (i = 0; i < uio->uio_iovcnt; i++) {
 		iovp = &uio->uio_iov[i];
 		while (iovp->iov_len > 0) {
+			void *map = NULL;
+
 			/*
 			 * [mark the buffer busy for physical I/O]
 			 * (i.e. set B_PHYS (because it's an I/O to user
@@ -124,7 +126,6 @@ physio(void (*strategy)(struct buf *), struct buf *bp, dev_t dev, int flags,
 
 			/* [set up the buffer for a maximum-sized transfer] */
 			bp->b_blkno = btodb(uio->uio_offset);
-			bp->b_data = iovp->iov_base;
 
 			/*
 			 * Because iov_len is unsigned but b_bcount is signed,
@@ -157,15 +158,20 @@ physio(void (*strategy)(struct buf *), struct buf *bp, dev_t dev, int flags,
 			 * saves it in b_saveaddr.  However, vunmapbuf()
 			 * restores it.
 			 */
-			error = uvm_vslock(p, bp->b_data, todo,
+			error = uvm_vslock_device(p, iovp->iov_base, todo,
 			    (flags & B_READ) ?
-			    VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ);
+			    VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ, &map);
 			if (error) {
 				bp->b_flags |= B_ERROR;
 				bp->b_error = error;
 				goto after_unlock;
 			}
-			vmapbuf(bp, todo);
+			if (map) {
+				bp->b_data = map;
+			} else {
+				bp->b_data = iovp->iov_base;
+				vmapbuf(bp, todo);
+			}
 
 			/* [call strategy to start the transfer] */
 			(*strategy)(bp);
@@ -194,8 +200,9 @@ physio(void (*strategy)(struct buf *), struct buf *bp, dev_t dev, int flags,
 			 * [unlock the part of the address space previously
 			 *    locked]
 			 */
-			vunmapbuf(bp, todo);
-			uvm_vsunlock(p, bp->b_data, todo);
+			if (!map)
+				vunmapbuf(bp, todo);
+			uvm_vsunlock_device(p, iovp->iov_base, todo, map);
 after_unlock:
 
 			/* remember error value (save a splbio/splx pair) */