Remove Giant from CAM. Drivers (SIMs) now register a mutex that CAM will

use to synchornize and protect all data objects that are used for that
SIM.  Drivers that are not yet MPSAFE register Giant and operate as
usual.  RIght now, no drivers are MPSAFE, though a few will be changed
in the coming week as this work settles down.

The driver API has changed, so all CAM drivers will need to be recompiled.
The userland API has not changed, so tools like camcontrol do not need to
be recompiled.

1 files changed, 32 insertions, 27 deletions

diff --git a/sys/cam/cam_sim.c b/sys/cam/cam_sim.c
index 322915f..cc8f86d 100644
--- a/sys/cam/cam_sim.c
+++ b/sys/cam/cam_sim.c
@@ -33,6 +33,8 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/malloc.h>
 #include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
 
 #include <cam/cam.h>
 #include <cam/cam_ccb.h>
@@ -58,39 +60,42 @@ cam_simq_free(struct cam_devq *devq)
 struct cam_sim *
 cam_sim_alloc(sim_action_func sim_action, sim_poll_func sim_poll,
 	      const char *sim_name, void *softc, u_int32_t unit,
-	      int max_dev_transactions,
+	      struct mtx *mtx, int max_dev_transactions,
 	      int max_tagged_dev_transactions, struct cam_devq *queue)
 {
 	struct cam_sim *sim;
 
-	/*
-	 * If this is the xpt layer creating a sim, then it's OK
-	 * to wait for an allocation.
-	 *
-	 * XXX Should we pass in a flag to indicate that wait is OK?
-	 */
-	if (strcmp(sim_name, "xpt") == 0)
-		sim = (struct cam_sim *)malloc(sizeof(struct cam_sim),
-					       M_CAMSIM, M_WAITOK);
-	else
-		sim = (struct cam_sim *)malloc(sizeof(struct cam_sim),
-					       M_CAMSIM, M_NOWAIT);
-
-	if (sim != NULL) {
-		sim->sim_action = sim_action;
-		sim->sim_poll = sim_poll;
-		sim->sim_name = sim_name;
-		sim->softc = softc;
-		sim->path_id = CAM_PATH_ANY;
-		sim->unit_number = unit;
-		sim->bus_id = 0;	/* set in xpt_bus_register */
-		sim->max_tagged_dev_openings = max_tagged_dev_transactions;
-		sim->max_dev_openings = max_dev_transactions;
-		sim->flags = 0;
-		callout_handle_init(&sim->c_handle);
-		sim->devq = queue;
+	if (mtx == NULL)
+		return (NULL);
+
+	sim = (struct cam_sim *)malloc(sizeof(struct cam_sim),
+	    M_CAMSIM, M_NOWAIT);
+
+	if (sim == NULL)
+		return (NULL);
+
+	sim->sim_action = sim_action;
+	sim->sim_poll = sim_poll;
+	sim->sim_name = sim_name;
+	sim->softc = softc;
+	sim->path_id = CAM_PATH_ANY;
+	sim->unit_number = unit;
+	sim->bus_id = 0;	/* set in xpt_bus_register */
+	sim->max_tagged_dev_openings = max_tagged_dev_transactions;
+	sim->max_dev_openings = max_dev_transactions;
+	sim->flags = 0;
+	sim->devq = queue;
+	sim->mtx = mtx;
+	if (mtx == &Giant) {
+		sim->flags |= 0;
+		callout_init(&sim->callout, 0);
+	} else {
+		sim->flags |= CAM_SIM_MPSAFE;
+		callout_init(&sim->callout, 1);
 	}
 
+	SLIST_INIT(&sim->ccb_freeq);
+
 	return (sim);
 }