[src/trunk]: src/sys/arch/xen/xen remove code handling buffers not aligned to...

[jdolecek <jdolecek%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/dfc07ce2b61b
branches:  trunk
changeset: 834645:dfc07ce2b61b
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Tue Aug 21 18:31:55 2018 +0000

description:
remove code handling buffers not aligned to 512-byte boundary, simply return
EINVAL straight away

the condition doesn't seem to be actually hit for normal boots and
tools like fsck, which is good thing since it allocated memory
separately for each such I/O

diffstat:

 sys/arch/xen/xen/xbd_xenbus.c |  60 +++++++-----------------------------------
 1 files changed, 10 insertions(+), 50 deletions(-)

diffs (121 lines):

diff -r 4000f42e54a8 -r dfc07ce2b61b sys/arch/xen/xen/xbd_xenbus.c
--- a/sys/arch/xen/xen/xbd_xenbus.c     Tue Aug 21 18:11:10 2018 +0000
+++ b/sys/arch/xen/xen/xbd_xenbus.c     Tue Aug 21 18:31:55 2018 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: xbd_xenbus.c,v 1.83 2018/08/21 18:11:10 jdolecek Exp $      */
+/*      $NetBSD: xbd_xenbus.c,v 1.84 2018/08/21 18:31:55 jdolecek Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -50,7 +50,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.83 2018/08/21 18:11:10 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.84 2018/08/21 18:31:55 jdolecek Exp $");
 
 #include "opt_xen.h"
 
@@ -105,7 +105,6 @@
                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 +115,6 @@
 #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 {
@@ -171,9 +169,6 @@
 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),
@@ -703,9 +698,6 @@
                }
                /* b_resid was set in dk_start */
 next:
-               if (bp->b_data != xbdreq->req_data)
-                       xbd_unmap_align(xbdreq);
-
                dk_done(&sc->sc_dksc, bp);
 
                SLIST_INSERT_HEAD(&sc->sc_xbdreq_head, xbdreq, req_next);
@@ -972,15 +964,13 @@
                goto out;
        }
 
+       if ((vaddr_t)bp->b_data & (XEN_BSIZE - 1)) {
+               DPRINTF(("xbd_diskstart: no align\n"));
+               error = EINVAL;
+               goto out;
+       }
+
        xbdreq->req_bp = bp;
-       xbdreq->req_data = bp->b_data;
-       if ((vaddr_t)bp->b_data & (XEN_BSIZE - 1)) {
-               if (__predict_false(xbd_map_align(xbdreq) != 0)) {
-                       DPRINTF(("xbd_diskstart: no align\n"));
-                       error = EAGAIN;
-                       goto out;
-               }
-       }
 
        SLIST_REMOVE_HEAD(&sc->sc_xbdreq_head, req_next);
        req = RING_GET_REQUEST(&sc->sc_ring, sc->sc_ring.req_prod_pvt);
@@ -990,8 +980,8 @@
        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;) {
@@ -1031,33 +1021,3 @@
 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);
-}