revert previous - physio arranges for tranfer directly to user-provided
buffers, which are generally not DEV_BSIZE-aligned
This commit is contained in:
jdolecek
parent
09a46b6e04
commit
e9acb25cbb
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@ -1,4 +1,4 @@
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/* $NetBSD: xbd_xenbus.c,v 1.102 2020/04/11 16:15:34 jdolecek Exp $ */
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/* $NetBSD: xbd_xenbus.c,v 1.103 2020/04/11 17:52:01 jdolecek Exp $ */
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/*
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* Copyright (c) 2006 Manuel Bouyer.
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@ -50,7 +50,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.102 2020/04/11 16:15:34 jdolecek Exp $");
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__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.103 2020/04/11 17:52:01 jdolecek Exp $");
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#include "opt_xen.h"
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@ -97,8 +97,6 @@ __KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.102 2020/04/11 16:15:34 jdolecek Ex
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#define XEN_BSHIFT 9 /* log2(XEN_BSIZE) */
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#define XEN_BSIZE (1 << XEN_BSHIFT)
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__CTASSERT((DEV_BSIZE == XEN_BSIZE));
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struct xbd_req {
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SLIST_ENTRY(xbd_req) req_next;
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uint16_t req_id; /* ID passed to backend */
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@ -107,6 +105,7 @@ struct xbd_req {
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grant_ref_t req_gntref[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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int req_nr_segments; /* number of segments in this request */
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struct buf *req_bp; /* buffer associated with this request */
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void *req_data; /* pointer to the data buffer */
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} req_rw;
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struct {
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int s_error;
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@ -117,6 +116,7 @@ struct xbd_req {
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#define req_gntref u.req_rw.req_gntref
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#define req_nr_segments u.req_rw.req_nr_segments
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#define req_bp u.req_rw.req_bp
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#define req_data u.req_rw.req_data
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#define req_sync u.req_sync
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struct xbd_xenbus_softc {
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@ -156,6 +156,7 @@ struct xbd_xenbus_softc {
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#define BLKIF_FEATURE_PERSISTENT 0x4
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#define BLKIF_FEATURE_BITS \
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"\20\1CACHE-FLUSH\2BARRIER\3PERSISTENT"
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struct evcnt sc_cnt_map_unalign;
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};
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#if 0
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@ -176,6 +177,9 @@ static int xbd_diskstart(device_t, struct buf *);
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static void xbd_backend_changed(void *, XenbusState);
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static void xbd_connect(struct xbd_xenbus_softc *);
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static int xbd_map_align(struct xbd_req *);
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static void xbd_unmap_align(struct xbd_req *);
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static void xbdminphys(struct buf *);
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CFATTACH_DECL3_NEW(xbd, sizeof(struct xbd_xenbus_softc),
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@ -281,6 +285,9 @@ xbd_xenbus_attach(device_t parent, device_t self, void *aux)
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panic("%s: can't alloc ring", device_xname(self));
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sc->sc_ring.sring = ring;
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evcnt_attach_dynamic(&sc->sc_cnt_map_unalign, EVCNT_TYPE_MISC,
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NULL, device_xname(self), "map unaligned");
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/* resume shared structures and tell backend that we are ready */
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if (xbd_xenbus_resume(self, PMF_Q_NONE) == false) {
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uvm_km_free(kernel_map, (vaddr_t)ring, PAGE_SIZE,
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@ -364,6 +371,8 @@ xbd_xenbus_detach(device_t dev, int flags)
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uvm_km_free(kernel_map, (vaddr_t)sc->sc_ring.sring,
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PAGE_SIZE, UVM_KMF_WIRED);
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evcnt_detach(&sc->sc_cnt_map_unalign);
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pmf_device_deregister(dev);
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return 0;
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@ -702,6 +711,9 @@ again:
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goto next;
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}
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/* b_resid was set in dk_start */
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if (__predict_false(
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xbdreq->req_data != NULL && bp->b_data != xbdreq->req_data))
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xbd_unmap_align(xbdreq);
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next:
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xbdreq->req_bp = NULL;
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dk_done(&sc->sc_dksc, bp);
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@ -971,13 +983,16 @@ xbd_diskstart(device_t self, struct buf *bp)
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}
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xbdreq->req_bp = bp;
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xbdreq->req_data = bp->b_data;
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if (__predict_false((vaddr_t)bp->b_data & (XEN_BSIZE - 1))) {
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sc->sc_cnt_map_unalign.ev_count++;
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/*
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* All bufs passed by system are aligned to DEV_BSIZE.
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* xbd requires this to be the case, as transfer offsets
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* are expressed in multiplies of 512 (XEN_BSIZE).
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*/
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KASSERT(((vaddr_t)bp->b_data & (XEN_BSIZE - 1)) == 0);
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if (__predict_false(xbd_map_align(xbdreq) != 0)) {
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DPRINTF(("xbd_diskstart: no align\n"));
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error = EAGAIN;
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goto out;
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}
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}
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SLIST_REMOVE_HEAD(&sc->sc_xbdreq_head, req_next);
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req = RING_GET_REQUEST(&sc->sc_ring, sc->sc_ring.req_prod_pvt);
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@ -987,8 +1002,8 @@ xbd_diskstart(device_t self, struct buf *bp)
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req->sector_number = bp->b_rawblkno;
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req->handle = sc->sc_handle;
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va = (vaddr_t)bp->b_data & ~PAGE_MASK;
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off = (vaddr_t)bp->b_data & PAGE_MASK;
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va = (vaddr_t)xbdreq->req_data & ~PAGE_MASK;
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off = (vaddr_t)xbdreq->req_data & PAGE_MASK;
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bcount = bp->b_bcount;
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bp->b_resid = 0;
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for (seg = 0; bcount > 0;) {
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@ -1028,3 +1043,33 @@ out:
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err:
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return error;
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}
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static int
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xbd_map_align(struct xbd_req *req)
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{
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int s = splvm(); /* XXXSMP - bogus? */
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int rc;
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rc = uvm_km_kmem_alloc(kmem_va_arena,
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req->req_bp->b_bcount, (VM_NOSLEEP | VM_INSTANTFIT),
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(vmem_addr_t *)&req->req_data);
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splx(s);
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if (__predict_false(rc != 0))
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return ENOMEM;
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if ((req->req_bp->b_flags & B_READ) == 0)
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memcpy(req->req_data, req->req_bp->b_data,
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req->req_bp->b_bcount);
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return 0;
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}
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static void
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xbd_unmap_align(struct xbd_req *req)
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{
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int s;
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if (req->req_bp->b_flags & B_READ)
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memcpy(req->req_bp->b_data, req->req_data,
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req->req_bp->b_bcount);
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s = splvm(); /* XXXSMP - bogus? */
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uvm_km_kmem_free(kmem_va_arena, (vaddr_t)req->req_data, req->req_bp->b_bcount);
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splx(s);
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}
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