1/*-
2 * CAM request queue management definitions.
3 *
4 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
5 *
6 * Copyright (c) 1997 Justin T. Gibbs.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions, and the following disclaimer,
14 *    without modification, immediately at the beginning of the file.
15 * 2. The name of the author may not be used to endorse or promote products
16 *    derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $FreeBSD$
31 */
32
33#ifndef _CAM_CAM_QUEUE_H
34#define _CAM_CAM_QUEUE_H 1
35
36#ifdef _KERNEL
37
38#include <sys/lock.h>
39#include <sys/mutex.h>
40#include <sys/queue.h>
41#include <cam/cam.h>
42
43/*
44 * This structure implements a heap based priority queue.  The queue
45 * assumes that the objects stored in it begin with a cam_qentry
46 * structure holding the priority information used to sort the objects.
47 * This structure is opaque to clients (outside of the XPT layer) to allow
48 * the implementation to change without affecting them.
49 */
50struct camq {
51	cam_pinfo **queue_array;
52	int	   array_size;
53	int	   entries;
54	u_int32_t  generation;
55	u_int32_t  qfrozen_cnt;
56};
57
58TAILQ_HEAD(ccb_hdr_tailq, ccb_hdr);
59LIST_HEAD(ccb_hdr_list, ccb_hdr);
60SLIST_HEAD(ccb_hdr_slist, ccb_hdr);
61
62struct cam_ccbq {
63	struct	camq queue;
64	struct ccb_hdr_tailq	queue_extra_head;
65	int	queue_extra_entries;
66	int	total_openings;
67	int	allocated;
68	int	dev_openings;
69	int	dev_active;
70};
71
72struct cam_ed;
73
74struct cam_devq {
75	struct mtx	 send_mtx;
76	struct camq	 send_queue;
77	int		 send_openings;
78	int		 send_active;
79};
80
81
82struct cam_devq *cam_devq_alloc(int devices, int openings);
83
84int		 cam_devq_init(struct cam_devq *devq, int devices,
85			       int openings);
86
87void		 cam_devq_free(struct cam_devq *devq);
88
89u_int32_t	 cam_devq_resize(struct cam_devq *camq, int openings);
90
91/*
92 * Allocate a cam_ccb_queue structure and initialize it.
93 */
94struct cam_ccbq	*cam_ccbq_alloc(int openings);
95
96u_int32_t	cam_ccbq_resize(struct cam_ccbq *ccbq, int devices);
97
98int		cam_ccbq_init(struct cam_ccbq *ccbq, int openings);
99
100void		cam_ccbq_free(struct cam_ccbq *ccbq);
101
102void		cam_ccbq_fini(struct cam_ccbq *ccbq);
103
104/*
105 * Allocate and initialize a cam_queue structure.
106 */
107struct camq	*camq_alloc(int size);
108
109/*
110 * Resize a cam queue
111 */
112u_int32_t	camq_resize(struct camq *queue, int new_size);
113
114/*
115 * Initialize a camq structure.  Return 0 on success, 1 on failure.
116 */
117int		camq_init(struct camq *camq, int size);
118
119/*
120 * Free a cam_queue structure.  This should only be called if a controller
121 * driver failes somehow during its attach routine or is unloaded and has
122 * obtained a cam_queue structure.
123 */
124void		camq_free(struct camq *queue);
125
126/*
127 * Finialize any internal storage or state of a cam_queue.
128 */
129void		camq_fini(struct camq *queue);
130
131/*
132 * cam_queue_insert: Given a CAM queue with at least one open spot,
133 * insert the new entry maintaining order.
134 */
135void		camq_insert(struct camq *queue, cam_pinfo *new_entry);
136
137/*
138 * camq_remove: Remove and arbitrary entry from the queue maintaining
139 * queue order.
140 */
141cam_pinfo	*camq_remove(struct camq *queue, int index);
142#define CAMQ_HEAD 1	/* Head of queue index */
143
144/* Index the first element in the heap */
145#define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
146
147/* Get the first element priority. */
148#define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ?			\
149			    ((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
150
151/*
152 * camq_change_priority: Raise or lower the priority of an entry
153 * maintaining queue order.
154 */
155void		camq_change_priority(struct camq *queue, int index,
156				     u_int32_t new_priority);
157
158static __inline int
159cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq);
160
161static __inline void
162cam_ccbq_take_opening(struct cam_ccbq *ccbq);
163
164static __inline void
165cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb);
166
167static __inline void
168cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb);
169
170static __inline union ccb *
171cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index);
172
173static __inline void
174cam_ccbq_send_ccb(struct cam_ccbq *queue, union ccb *send_ccb);
175
176static __inline void
177cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb);
178
179static __inline void
180cam_ccbq_release_opening(struct cam_ccbq *ccbq);
181
182
183static __inline int
184cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
185{
186	return (ccbq->queue.entries + ccbq->queue_extra_entries);
187}
188
189static __inline void
190cam_ccbq_take_opening(struct cam_ccbq *ccbq)
191{
192
193	ccbq->allocated++;
194}
195
196static __inline void
197cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
198{
199	struct ccb_hdr *old_ccb;
200	struct camq *queue = &ccbq->queue;
201
202	KASSERT((new_ccb->ccb_h.func_code & XPT_FC_QUEUED) != 0 &&
203	    (new_ccb->ccb_h.func_code & XPT_FC_USER_CCB) == 0,
204	    ("%s: Cannot queue ccb %p func_code %#x", __func__, new_ccb,
205	     new_ccb->ccb_h.func_code));
206
207	/*
208	 * If queue is already full, try to resize.
209	 * If resize fail, push CCB with lowest priority out to the TAILQ.
210	 */
211	if (queue->entries == queue->array_size &&
212	    camq_resize(&ccbq->queue, queue->array_size * 2) != CAM_REQ_CMP) {
213		old_ccb = (struct ccb_hdr *)camq_remove(queue, queue->entries);
214		TAILQ_INSERT_HEAD(&ccbq->queue_extra_head, old_ccb,
215		    xpt_links.tqe);
216		old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
217		ccbq->queue_extra_entries++;
218	}
219
220	camq_insert(queue, &new_ccb->ccb_h.pinfo);
221}
222
223static __inline void
224cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
225{
226	struct ccb_hdr *cccb, *bccb;
227	struct camq *queue = &ccbq->queue;
228	cam_pinfo *removed_entry __unused;
229
230	/* If the CCB is on the TAILQ, remove it from there. */
231	if (ccb->ccb_h.pinfo.index == CAM_EXTRAQ_INDEX) {
232		TAILQ_REMOVE(&ccbq->queue_extra_head, &ccb->ccb_h,
233		    xpt_links.tqe);
234		ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
235		ccbq->queue_extra_entries--;
236		return;
237	}
238
239	removed_entry = camq_remove(queue, ccb->ccb_h.pinfo.index);
240	KASSERT(removed_entry == &ccb->ccb_h.pinfo,
241	    ("%s: Removed wrong entry from queue (%p != %p)", __func__,
242	     removed_entry, &ccb->ccb_h.pinfo));
243
244	/*
245	 * If there are some CCBs on TAILQ, find the best one and move it
246	 * to the emptied space in the queue.
247	 */
248	bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
249	if (bccb == NULL)
250		return;
251	TAILQ_FOREACH(cccb, &ccbq->queue_extra_head, xpt_links.tqe) {
252		if (bccb->pinfo.priority > cccb->pinfo.priority ||
253		    (bccb->pinfo.priority == cccb->pinfo.priority &&
254		     GENERATIONCMP(bccb->pinfo.generation, >,
255		      cccb->pinfo.generation)))
256		        bccb = cccb;
257	}
258	TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
259	ccbq->queue_extra_entries--;
260	camq_insert(queue, &bccb->pinfo);
261}
262
263static __inline union ccb *
264cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
265{
266	return((union ccb *)ccbq->queue.queue_array[index]);
267}
268
269static __inline void
270cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
271{
272
273	send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
274	ccbq->dev_active++;
275	ccbq->dev_openings--;
276}
277
278static __inline void
279cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
280{
281
282	ccbq->dev_active--;
283	ccbq->dev_openings++;
284}
285
286static __inline void
287cam_ccbq_release_opening(struct cam_ccbq *ccbq)
288{
289
290	ccbq->allocated--;
291}
292
293#endif /* _KERNEL */
294#endif  /* _CAM_CAM_QUEUE_H */
295