svn commit: r248516 - head/sys/geom

[Konstantin Belousov]

Author: kib
Date: Tue Mar 19 14:49:15 2013
New Revision: 248516
URL: http://svnweb.freebsd.org/changeset/base/248516

Log:
  A flag for the geom disk driver to indicate that it accepts the
  unmapped i/o requests.
  
  Sponsored by:	The FreeBSD Foundation
  Tested by:	pho

Modified:
  head/sys/geom/geom_disk.c
  head/sys/geom/geom_disk.h

Modified: head/sys/geom/geom_disk.c
==============================================================================
--- head/sys/geom/geom_disk.c	Tue Mar 19 14:43:57 2013	(r248515)
+++ head/sys/geom/geom_disk.c	Tue Mar 19 14:49:15 2013	(r248516)
@@ -320,13 +320,29 @@ g_disk_start(struct bio *bp)
 		do {
 			bp2->bio_offset += off;
 			bp2->bio_length -= off;
-			bp2->bio_data += off;
+			if ((bp->bio_flags & BIO_UNMAPPED) == 0) {
+				bp2->bio_data += off;
+			} else {
+				KASSERT((dp->d_flags & DISKFLAG_UNMAPPED_BIO)
+				    != 0,
+				    ("unmapped bio not supported by disk %s",
+				    dp->d_name));
+				bp2->bio_ma += off / PAGE_SIZE;
+				bp2->bio_ma_offset += off;
+				bp2->bio_ma_offset %= PAGE_SIZE;
+				bp2->bio_ma_n -= off / PAGE_SIZE;
+			}
 			if (bp2->bio_length > dp->d_maxsize) {
 				/*
 				 * XXX: If we have a stripesize we should really
 				 * use it here.
 				 */
 				bp2->bio_length = dp->d_maxsize;
+				if ((bp->bio_flags & BIO_UNMAPPED) != 0) {
+					bp2->bio_ma_n = howmany(
+					    bp2->bio_ma_offset +
+					    bp2->bio_length, PAGE_SIZE);
+				}
 				off += dp->d_maxsize;
 				/*
 				 * To avoid a race, we need to grab the next bio
@@ -488,6 +504,8 @@ g_disk_create(void *arg, int flag)
 	pp->sectorsize = dp->d_sectorsize;
 	pp->stripeoffset = dp->d_stripeoffset;
 	pp->stripesize = dp->d_stripesize;
+	if ((dp->d_flags & DISKFLAG_UNMAPPED_BIO) != 0)
+		pp->flags |= G_PF_ACCEPT_UNMAPPED;
 	if (bootverbose)
 		printf("GEOM: new disk %s\n", gp->name);
 	sysctl_ctx_init(&sc->sysctl_ctx);

Modified: head/sys/geom/geom_disk.h
==============================================================================
--- head/sys/geom/geom_disk.h	Tue Mar 19 14:43:57 2013	(r248515)
+++ head/sys/geom/geom_disk.h	Tue Mar 19 14:49:15 2013	(r248516)
@@ -103,6 +103,7 @@ struct disk {
 #define DISKFLAG_OPEN		0x2
 #define DISKFLAG_CANDELETE	0x4
 #define DISKFLAG_CANFLUSHCACHE	0x8
+#define	DISKFLAG_UNMAPPED_BIO	0x10
 
 struct disk *disk_alloc(void);
 void disk_create(struct disk *disk, int version);