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XEN_BSIZE vs DEV_BSIZE in xbd(4) and xbdback(4)
Hi list,
What was the reason behind the XEN_BSIZE/VBD_BSIZE vs DEV_BSIZE split
(in current state, they are identical, eg. 9 bits/512 bytes)
The byte counts and nbytes are either calculated using DEV_BSIZE or
XEN_BSIZE, and IIRC, disk(9) with physical blocks != 512 bytes should be
implemented via disk_blocksize() and dk_blkshift elements.
FWIW:
--- xen/xbd_xenbus.c 2011年03月30日 02:13:28.000000000 +0200
+++ xen/xbd_xenbus.c 2011年05月03日 11:20:35.000000000 +0200
@@ -73,9 +73,6 @@ __KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c
#define XBD_RING_SIZE __RING_SIZE((blkif_sring_t *)0, PAGE_SIZE)
-#define XEN_BSHIFT 9 /* log2(XEN_BSIZE) */
-#define XEN_BSIZE (1 << XEN_BSHIFT)
-
struct xbd_req {
SLIST_ENTRY(xbd_req) req_next;
uint16_t req_id; /* ID passed to backend */
@@ -888,7 +885,7 @@ xbdstart(struct dk_softc *dksc, struct b
xbdreq->req_bp = bp;
xbdreq->req_data = bp->b_data;
- if ((vaddr_t)bp->b_data & (XEN_BSIZE - 1)) {
+ if ((vaddr_t)bp->b_data & (DEV_BSIZE - 1)) {
if (__predict_false(xbd_map_align(xbdreq) != 0)) {
ret = -1;
goto out;
@@ -914,14 +911,14 @@ xbdstart(struct dk_softc *dksc, struct b
}
for (seg = 0, bcount = bp->b_bcount; bcount > 0;) {
pmap_extract_ma(pmap_kernel(), va, &ma);
- KASSERT((ma & (XEN_BSIZE - 1)) == 0);
+ KASSERT((ma & (DEV_BSIZE - 1)) == 0);
if (bcount > PAGE_SIZE - off)
nbytes = PAGE_SIZE - off;
else
nbytes = bcount;
- nsects = nbytes >> XEN_BSHIFT;
- req->seg[seg].first_sect = off >> XEN_BSHIFT;
- req->seg[seg].last_sect = (off >> XEN_BSHIFT) + nsects
- 1;
+ nsects = nbytes >> DEV_BSHIFT;
+ req->seg[seg].first_sect = off >> DEV_BSHIFT;
+ req->seg[seg].last_sect = (off >> DEV_BSHIFT) + nsects
- 1;
KASSERT(req->seg[seg].first_sect <=
req->seg[seg].last_sect);
KASSERT(req->seg[seg].last_sect < 8);
if (__predict_false(xengnt_grant_access(
--- sys/arch/xen/xen/xbdback_xenbus.c 29 Apr 2011 22:58:46 -0000
1.34
+++ sys/arch/xen/xen/xbdback_xenbus.c 3 May 2011 09:40:05 -0000
@@ -66,8 +66,7 @@ __KERNEL_RCSID(0, "$NetBSD: xbdback_xenb
#define BLKIF_MAX_PAGES_PER_REQUEST (BLKIF_MAX_SEGMENTS_PER_REQUEST +
1)
/* Values are expressed in 512-byte sectors */
-#define VBD_BSIZE 512
-#define VBD_MAXSECT ((PAGE_SIZE / VBD_BSIZE) - 1)
+#define VBD_MAXSECT ((PAGE_SIZE / DEV_BSIZE) - 1)
struct xbdback_request;
struct xbdback_io;
@@ -1190,7 +1189,7 @@ xbdback_co_io_gotio(struct xbdback_insta
xbd_io->xio_mapped = 0;
xbd_io->xio_operation = xbdi->xbdi_xen_req.operation;
- start_offset = xbdi->xbdi_this_fs * VBD_BSIZE;
+ start_offset = xbdi->xbdi_this_fs * DEV_BSIZE;
if (xbdi->xbdi_xen_req.operation == BLKIF_OP_WRITE) {
buf_flags = B_WRITE;
@@ -1272,7 +1271,7 @@ xbdback_co_io_gotfrag2(struct xbdback_in
xbd_io->xio_gref[xbd_io->xio_nrma++] =
xbdi->xbdi_thisgrt;
}
- xbd_io->xio_buf.b_bcount += (daddr_t)(seg_size * VBD_BSIZE);
+ xbd_io->xio_buf.b_bcount += (daddr_t)(seg_size * DEV_BSIZE);
XENPRINTF(("xbdback_io domain %d: start sect %d size %d\n",
xbdi->xbdi_domid, (int)xbdi->xbdi_next_sector, seg_size));
--
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost
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