[src/trunk]: src/sys/miscfs/genfs don't block on pager map for read-ahead.

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

details:   https://anonhg.NetBSD.org/src/rev/f88c06667cde
branches:  trunk
changeset: 779355:f88c06667cde
user:      yamt <yamt%NetBSD.org@localhost>
date:      Tue May 22 14:20:39 2012 +0000

description:
don't block on pager map for read-ahead.
reduce code duplication.

diffstat:

 sys/miscfs/genfs/genfs_io.c |  40 ++++++++++++++++------------------------
 1 files changed, 16 insertions(+), 24 deletions(-)

diffs (98 lines):

diff -r 42637ba2b63b -r f88c06667cde sys/miscfs/genfs/genfs_io.c
--- a/sys/miscfs/genfs/genfs_io.c       Tue May 22 09:23:39 2012 +0000
+++ b/sys/miscfs/genfs/genfs_io.c       Tue May 22 14:20:39 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: genfs_io.c,v 1.54 2012/04/29 22:54:00 chs Exp $        */
+/*     $NetBSD: genfs_io.c,v 1.55 2012/05/22 14:20:39 yamt Exp $       */
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: genfs_io.c,v 1.54 2012/04/29 22:54:00 chs Exp $");
+__KERNEL_RCSID(0, "$NetBSD: genfs_io.c,v 1.55 2012/05/22 14:20:39 yamt Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -58,21 +58,22 @@
 
 static int genfs_do_io(struct vnode *, off_t, vaddr_t, size_t, int, enum uio_rw,
     void (*)(struct buf *));
-static void genfs_rel_pages(struct vm_page **, int);
+static void genfs_rel_pages(struct vm_page **, unsigned int);
 static void genfs_markdirty(struct vnode *);
 
 int genfs_maxdio = MAXPHYS;
 
 static void
-genfs_rel_pages(struct vm_page **pgs, int npages)
+genfs_rel_pages(struct vm_page **pgs, unsigned int npages)
 {
-       int i;
+       unsigned int i;
 
        for (i = 0; i < npages; i++) {
                struct vm_page *pg = pgs[i];
 
                if (pg == NULL || pg == PGO_DONTCARE)
                        continue;
+               KASSERT(uvm_page_locked_p(pg));
                if (pg->flags & PG_FAKE) {
                        pg->flags |= PG_RELEASED;
                }
@@ -437,7 +438,11 @@
        skipbytes = 0;
 
        kva = uvm_pagermapin(pgs, npages,
-           UVMPAGER_MAPIN_READ | UVMPAGER_MAPIN_WAITOK);
+           UVMPAGER_MAPIN_READ | (async ? 0 : UVMPAGER_MAPIN_WAITOK));
+       if (kva == 0) {
+               error = EBUSY;
+               goto mapin_fail;
+       }
 
        mbp = getiobuf(vp, true);
        mbp->b_bufsize = totalbytes;
@@ -651,13 +656,14 @@
                        mutex_exit(uobj->vmobjlock);
                }
        }
-       if (!glocked) {
-               genfs_node_unlock(vp);
-       }
 
        putiobuf(mbp);
     }
 
+mapin_fail:
+       if (!glocked) {
+               genfs_node_unlock(vp);
+       }
        mutex_enter(uobj->vmobjlock);
 
        /*
@@ -668,21 +674,7 @@
         */
 
        if (error) {
-               for (i = 0; i < npages; i++) {
-                       struct vm_page *pg = pgs[i];
-
-                       if (pg == NULL) {
-                               continue;
-                       }
-                       UVMHIST_LOG(ubchist, "examining pg %p flags 0x%x",
-                           pg, pg->flags, 0,0);
-                       if (pg->flags & PG_FAKE) {
-                               pg->flags |= PG_RELEASED;
-                       }
-               }
-               mutex_enter(&uvm_pageqlock);
-               uvm_page_unbusy(pgs, npages);
-               mutex_exit(&uvm_pageqlock);
+               genfs_rel_pages(pgs, npages);
                mutex_exit(uobj->vmobjlock);
                UVMHIST_LOG(ubchist, "returning error %d", error,0,0,0);
                goto out_err_free;