svn commit: r186185 - head/sys/cam
Edward Tomasz Napierala
trasz at FreeBSD.org
Tue Dec 16 16:57:34 UTC 2008
Author: trasz
Date: Tue Dec 16 16:57:33 2008
New Revision: 186185
URL: http://svn.freebsd.org/changeset/base/186185
Log:
Add SIM refcounting. This is slightly different from what DragonFly
does - in DragonFly, it's cam_sim_release() what actually frees the
SIM; cam_sim_free does nothing more than calling cam_sim_release().
Here, we drain in cam_sim_free, waiting for refcount to drop to zero.
We cannot do the same think DragonFly does, because after cam_sim_free
returns, client would destroy the sim->mtx, and CAM would trip over
an initialized mutex.
Reviewed by: scottl
Approved by: rwatson (mentor)
Sponsored by: FreeBSD Foundation
Modified:
head/sys/cam/cam_sim.c
head/sys/cam/cam_sim.h
head/sys/cam/cam_xpt.c
Modified: head/sys/cam/cam_sim.c
==============================================================================
--- head/sys/cam/cam_sim.c Tue Dec 16 16:54:51 2008 (r186184)
+++ head/sys/cam/cam_sim.c Tue Dec 16 16:57:33 2008 (r186185)
@@ -84,6 +84,7 @@ cam_sim_alloc(sim_action_func sim_action
sim->max_tagged_dev_openings = max_tagged_dev_transactions;
sim->max_dev_openings = max_dev_transactions;
sim->flags = 0;
+ sim->refcount = 1;
sim->devq = queue;
sim->mtx = mtx;
if (mtx == &Giant) {
@@ -103,12 +104,40 @@ cam_sim_alloc(sim_action_func sim_action
void
cam_sim_free(struct cam_sim *sim, int free_devq)
{
+ int error;
+
+ sim->refcount--;
+ if (sim->refcount > 0) {
+ error = msleep(sim, sim->mtx, PRIBIO, "simfree", 0);
+ KASSERT(error == 0, ("invalid error value for msleep(9)"));
+ }
+
+ KASSERT(sim->refcount == 0, ("sim->refcount == 0"));
+
if (free_devq)
cam_simq_free(sim->devq);
free(sim, M_CAMSIM);
}
void
+cam_sim_release(struct cam_sim *sim)
+{
+ KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
+
+ sim->refcount--;
+ if (sim->refcount <= 1)
+ wakeup(sim);
+}
+
+void
+cam_sim_hold(struct cam_sim *sim)
+{
+ KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
+
+ sim->refcount++;
+}
+
+void
cam_sim_set_path(struct cam_sim *sim, u_int32_t path_id)
{
sim->path_id = path_id;
Modified: head/sys/cam/cam_sim.h
==============================================================================
--- head/sys/cam/cam_sim.h Tue Dec 16 16:54:51 2008 (r186184)
+++ head/sys/cam/cam_sim.h Tue Dec 16 16:57:33 2008 (r186185)
@@ -61,6 +61,8 @@ struct cam_sim * cam_sim_alloc(sim_acti
int max_tagged_dev_transactions,
struct cam_devq *queue);
void cam_sim_free(struct cam_sim *sim, int free_devq);
+void cam_sim_hold(struct cam_sim *sim);
+void cam_sim_release(struct cam_sim *sim);
/* Optional sim attributes may be set with these. */
void cam_sim_set_path(struct cam_sim *sim, u_int32_t path_id);
@@ -105,6 +107,7 @@ struct cam_sim {
#define CAM_SIM_ON_DONEQ 0x04
struct callout callout;
struct cam_devq *devq; /* Device Queue to use for this SIM */
+ int refcount; /* References to the SIM. */
/* "Pool" of inactive ccbs managed by xpt_alloc_ccb and xpt_free_ccb */
SLIST_HEAD(,ccb_hdr) ccb_freeq;
Modified: head/sys/cam/cam_xpt.c
==============================================================================
--- head/sys/cam/cam_xpt.c Tue Dec 16 16:54:51 2008 (r186184)
+++ head/sys/cam/cam_xpt.c Tue Dec 16 16:57:33 2008 (r186185)
@@ -4304,6 +4304,7 @@ xpt_bus_register(struct cam_sim *sim, de
TAILQ_INIT(&new_bus->et_entries);
new_bus->path_id = sim->path_id;
+ cam_sim_hold(sim);
new_bus->sim = sim;
timevalclear(&new_bus->last_reset);
new_bus->flags = 0;
@@ -4846,6 +4847,7 @@ xpt_release_bus(struct cam_eb *bus)
TAILQ_REMOVE(&xsoftc.xpt_busses, bus, links);
xsoftc.bus_generation++;
mtx_unlock(&xsoftc.xpt_topo_lock);
+ cam_sim_release(bus->sim);
free(bus, M_CAMXPT);
}
}
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