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
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parent
96100101a8
commit
fa6099fda0
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=186185
@ -84,6 +84,7 @@ cam_sim_alloc(sim_action_func sim_action, sim_poll_func sim_poll,
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sim->max_tagged_dev_openings = max_tagged_dev_transactions;
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sim->max_dev_openings = max_dev_transactions;
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sim->flags = 0;
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sim->refcount = 1;
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sim->devq = queue;
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sim->mtx = mtx;
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if (mtx == &Giant) {
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@ -103,11 +104,39 @@ cam_sim_alloc(sim_action_func sim_action, sim_poll_func sim_poll,
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void
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cam_sim_free(struct cam_sim *sim, int free_devq)
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{
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int error;
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sim->refcount--;
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if (sim->refcount > 0) {
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error = msleep(sim, sim->mtx, PRIBIO, "simfree", 0);
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KASSERT(error == 0, ("invalid error value for msleep(9)"));
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}
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KASSERT(sim->refcount == 0, ("sim->refcount == 0"));
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if (free_devq)
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cam_simq_free(sim->devq);
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free(sim, M_CAMSIM);
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}
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void
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cam_sim_release(struct cam_sim *sim)
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{
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KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
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sim->refcount--;
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if (sim->refcount <= 1)
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wakeup(sim);
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}
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void
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cam_sim_hold(struct cam_sim *sim)
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{
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KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
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sim->refcount++;
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}
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void
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cam_sim_set_path(struct cam_sim *sim, u_int32_t path_id)
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{
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@ -61,6 +61,8 @@ struct cam_sim * cam_sim_alloc(sim_action_func sim_action,
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int max_tagged_dev_transactions,
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struct cam_devq *queue);
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void cam_sim_free(struct cam_sim *sim, int free_devq);
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void cam_sim_hold(struct cam_sim *sim);
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void cam_sim_release(struct cam_sim *sim);
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/* Optional sim attributes may be set with these. */
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void cam_sim_set_path(struct cam_sim *sim, u_int32_t path_id);
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@ -105,6 +107,7 @@ struct cam_sim {
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#define CAM_SIM_ON_DONEQ 0x04
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struct callout callout;
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struct cam_devq *devq; /* Device Queue to use for this SIM */
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int refcount; /* References to the SIM. */
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/* "Pool" of inactive ccbs managed by xpt_alloc_ccb and xpt_free_ccb */
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SLIST_HEAD(,ccb_hdr) ccb_freeq;
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@ -4304,6 +4304,7 @@ xpt_bus_register(struct cam_sim *sim, device_t parent, u_int32_t bus)
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TAILQ_INIT(&new_bus->et_entries);
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new_bus->path_id = sim->path_id;
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cam_sim_hold(sim);
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new_bus->sim = sim;
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timevalclear(&new_bus->last_reset);
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new_bus->flags = 0;
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@ -4846,6 +4847,7 @@ xpt_release_bus(struct cam_eb *bus)
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TAILQ_REMOVE(&xsoftc.xpt_busses, bus, links);
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xsoftc.bus_generation++;
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mtx_unlock(&xsoftc.xpt_topo_lock);
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cam_sim_release(bus->sim);
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free(bus, M_CAMXPT);
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}
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}
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