[Midnightbsd-cvs] src [9281] trunk/sys/cam/ata/ata_da.c: add a callback to the ada(4) driver so that it knows when GEOM has released references to it.

[laffer1 at midnightbsd.org]

Revision: 9281
          http://svnweb.midnightbsd.org/src/?rev=9281
Author:   laffer1
Date:     2017-03-02 17:57:14 -0500 (Thu, 02 Mar 2017)
Log Message:
-----------
add a callback to the ada(4) driver so that it knows when GEOM has released references to it. (freebsd svn 249661)

Modified Paths:
--------------
    trunk/sys/cam/ata/ata_da.c

Modified: trunk/sys/cam/ata/ata_da.c
===================================================================
--- trunk/sys/cam/ata/ata_da.c	2017-02-20 03:23:36 UTC (rev 9280)
+++ trunk/sys/cam/ata/ata_da.c	2017-03-02 22:57:14 UTC (rev 9281)
@@ -938,7 +938,21 @@
 	}
 }
 
+/*
+ * Callback from GEOM, called when it has finished cleaning up its
+ * resources.
+ */
 static void
+adadiskgonecb(struct disk *dp)
+{
+	struct cam_periph *periph;
+
+	periph = (struct cam_periph *)dp->d_drv1;
+
+	cam_periph_release(periph);
+}
+
+static void
 adaoninvalidate(struct cam_periph *periph)
 {
 	struct ada_softc *softc;
@@ -1277,6 +1291,7 @@
 	softc->disk->d_strategy = adastrategy;
 	softc->disk->d_getattr = adagetattr;
 	softc->disk->d_dump = adadump;
+	softc->disk->d_gone = adadiskgonecb;
 	softc->disk->d_name = "ada";
 	softc->disk->d_drv1 = periph;
 	maxio = cpi.maxio;		/* Honor max I/O size of SIM */
@@ -1340,6 +1355,17 @@
 		}
 	} else
 		legacy_id = -1;
+	/*
+	 * Acquire a reference to the periph before we register with GEOM.
+	 * We'll release this reference once GEOM calls us back (via
+	 * adadiskgonecb()) telling us that our provider has been freed.
+	 */
+	if (cam_periph_acquire(periph) != CAM_REQ_CMP) {
+		xpt_print(periph->path, "%s: lost periph during "
+			  "registration!\n", __func__);
+		cam_periph_lock(periph);
+		return (CAM_REQ_CMP_ERR);
+	}
 	disk_create(softc->disk, DISK_VERSION);
 	cam_periph_lock(periph);
 	cam_periph_unhold(periph);