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now that getebuf() et.al. always returns DEV_BSIZE-aligned buffers 

and rest of kernel code doing disk I/O was also converted over to it,
it's finally safe to remove the code to handle misaligned buffers

leave just KASSERT() in place
This commit is contained in:
jdolecek 2020-04-11 16:15:34 +00:00
parent 46bb4d7779
commit b8ae4d6eb4
1 changed files with 12 additions and 57 deletions
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69
sys/arch/xen/xen/xbd_xenbus.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: xbd_xenbus.c,v 1.101 2020/04/11 16:02:41 jdolecek Exp $ */
/* $NetBSD: xbd_xenbus.c,v 1.102 2020/04/11 16:15:34 jdolecek Exp $ */
/*
* Copyright (c) 2006 Manuel Bouyer.
@ -50,7 +50,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.101 2020/04/11 16:02:41 jdolecek Exp $");
__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.102 2020/04/11 16:15:34 jdolecek Exp $");
#include "opt_xen.h"
@ -97,6 +97,8 @@ __KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.101 2020/04/11 16:02:41 jdolecek Ex
#define XEN_BSHIFT 9 /* log2(XEN_BSIZE) */
#define XEN_BSIZE (1 << XEN_BSHIFT)
__CTASSERT((DEV_BSIZE == XEN_BSIZE));
struct xbd_req {
SLIST_ENTRY(xbd_req) req_next;
uint16_t req_id; /* ID passed to backend */
@ -105,7 +107,6 @@ struct xbd_req {
grant_ref_t req_gntref[BLKIF_MAX_SEGMENTS_PER_REQUEST];
int req_nr_segments; /* number of segments in this request */
struct buf *req_bp; /* buffer associated with this request */
void *req_data; /* pointer to the data buffer */
} req_rw;
struct {
int s_error;
@ -116,7 +117,6 @@ struct xbd_req {
#define req_gntref u.req_rw.req_gntref
#define req_nr_segments u.req_rw.req_nr_segments
#define req_bp u.req_rw.req_bp
#define req_data u.req_rw.req_data
#define req_sync u.req_sync
struct xbd_xenbus_softc {
@ -156,7 +156,6 @@ struct xbd_xenbus_softc {
#define BLKIF_FEATURE_PERSISTENT 0x4
#define BLKIF_FEATURE_BITS \
"\20\1CACHE-FLUSH\2BARRIER\3PERSISTENT"
struct evcnt sc_cnt_map_unalign;
};
#if 0
@ -177,9 +176,6 @@ static int xbd_diskstart(device_t, struct buf *);
static void xbd_backend_changed(void *, XenbusState);
static void xbd_connect(struct xbd_xenbus_softc *);
static int xbd_map_align(struct xbd_req *);
static void xbd_unmap_align(struct xbd_req *);
static void xbdminphys(struct buf *);
CFATTACH_DECL3_NEW(xbd, sizeof(struct xbd_xenbus_softc),
@ -285,9 +281,6 @@ xbd_xenbus_attach(device_t parent, device_t self, void *aux)
panic("%s: can't alloc ring", device_xname(self));
sc->sc_ring.sring = ring;
evcnt_attach_dynamic(&sc->sc_cnt_map_unalign, EVCNT_TYPE_MISC,
NULL, device_xname(self), "map unaligned");
/* resume shared structures and tell backend that we are ready */
if (xbd_xenbus_resume(self, PMF_Q_NONE) == false) {
uvm_km_free(kernel_map, (vaddr_t)ring, PAGE_SIZE,
@ -371,8 +364,6 @@ xbd_xenbus_detach(device_t dev, int flags)
uvm_km_free(kernel_map, (vaddr_t)sc->sc_ring.sring,
PAGE_SIZE, UVM_KMF_WIRED);
evcnt_detach(&sc->sc_cnt_map_unalign);
pmf_device_deregister(dev);
return 0;
@ -711,9 +702,6 @@ again:
goto next;
}
/* b_resid was set in dk_start */
if (__predict_false(
xbdreq->req_data != NULL && bp->b_data != xbdreq->req_data))
xbd_unmap_align(xbdreq);
next:
xbdreq->req_bp = NULL;
dk_done(&sc->sc_dksc, bp);
@ -983,16 +971,13 @@ xbd_diskstart(device_t self, struct buf *bp)
}
xbdreq->req_bp = bp;
xbdreq->req_data = bp->b_data;
if (__predict_false((vaddr_t)bp->b_data & (XEN_BSIZE - 1))) {
sc->sc_cnt_map_unalign.ev_count++;
if (__predict_false(xbd_map_align(xbdreq) != 0)) {
DPRINTF(("xbd_diskstart: no align\n"));
error = EAGAIN;
goto out;
}
}
/*
* All bufs passed by system are aligned to DEV_BSIZE.
* xbd requires this to be the case, as transfer offsets
* are expressed in multiplies of 512 (XEN_BSIZE).
*/
KASSERT(((vaddr_t)bp->b_data & (XEN_BSIZE - 1)) == 0);
SLIST_REMOVE_HEAD(&sc->sc_xbdreq_head, req_next);
req = RING_GET_REQUEST(&sc->sc_ring, sc->sc_ring.req_prod_pvt);
@ -1002,8 +987,8 @@ xbd_diskstart(device_t self, struct buf *bp)
req->sector_number = bp->b_rawblkno;
req->handle = sc->sc_handle;
va = (vaddr_t)xbdreq->req_data & ~PAGE_MASK;
off = (vaddr_t)xbdreq->req_data & PAGE_MASK;
va = (vaddr_t)bp->b_data & ~PAGE_MASK;
off = (vaddr_t)bp->b_data & PAGE_MASK;
bcount = bp->b_bcount;
bp->b_resid = 0;
for (seg = 0; bcount > 0;) {
@ -1043,33 +1028,3 @@ out:
err:
return error;
}
static int
xbd_map_align(struct xbd_req *req)
{
int s = splvm(); /* XXXSMP - bogus? */
int rc;
rc = uvm_km_kmem_alloc(kmem_va_arena,
req->req_bp->b_bcount, (VM_NOSLEEP | VM_INSTANTFIT),
(vmem_addr_t *)&req->req_data);
splx(s);
if (__predict_false(rc != 0))
return ENOMEM;
if ((req->req_bp->b_flags & B_READ) == 0)
memcpy(req->req_data, req->req_bp->b_data,
req->req_bp->b_bcount);
return 0;
}
static void
xbd_unmap_align(struct xbd_req *req)
{
int s;
if (req->req_bp->b_flags & B_READ)
memcpy(req->req_bp->b_data, req->req_data,
req->req_bp->b_bcount);
s = splvm(); /* XXXSMP - bogus? */
uvm_km_kmem_free(kmem_va_arena, (vaddr_t)req->req_data, req->req_bp->b_bcount);
splx(s);
}