Module Name: src
Committed By: jdolecek
Date: Sat Apr 11 16:15:34 UTC 2020
Modified Files:
src/sys/arch/xen/xen: xbd_xenbus.c
Log Message:
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
To generate a diff of this commit:
cvs rdiff -u -r1.101 -r1.102 src/sys/arch/xen/xen/xbd_xenbus.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/xen/xen/xbd_xenbus.c
diff -u src/sys/arch/xen/xen/xbd_xenbus.c:1.101 src/sys/arch/xen/xen/xbd_xenbus.c:1.102
--- src/sys/arch/xen/xen/xbd_xenbus.c:1.101 Sat Apr 11 16:02:41 2020
+++ src/sys/arch/xen/xen/xbd_xenbus.c Sat Apr 11 16:15:34 2020
@@ -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
#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, stru
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, devic
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 flag
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
}
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
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);
-}
