2 * XenBSD block device driver
4 * Copyright (c) 2010-2013 Spectra Logic Corporation
5 * Copyright (c) 2009 Scott Long, Yahoo!
6 * Copyright (c) 2009 Frank Suchomel, Citrix
7 * Copyright (c) 2009 Doug F. Rabson, Citrix
8 * Copyright (c) 2005 Kip Macy
9 * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
10 * Modifications by Mark A. Williamson are (c) Intel Research Cambridge
13 * Permission is hereby granted, free of charge, to any person obtaining a copy
14 * of this software and associated documentation files (the "Software"), to
15 * deal in the Software without restriction, including without limitation the
16 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
17 * sell copies of the Software, and to permit persons to whom the Software is
18 * furnished to do so, subject to the following conditions:
20 * The above copyright notice and this permission notice shall be included in
21 * all copies or substantial portions of the Software.
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
28 * DEALINGS IN THE SOFTWARE.
33 #ifndef __XEN_BLKFRONT_BLOCK_H__
34 #define __XEN_BLKFRONT_BLOCK_H__
35 #include <xen/blkif.h>
38 * Given a number of blkif segments, compute the maximum I/O size supported.
40 * \note This calculation assumes that all but the first and last segments
41 * of the I/O are fully utilized.
43 * \note We reserve a segement from the maximum supported by the transport to
44 * guarantee we can handle an unaligned transfer without the need to
45 * use a bounce buffer.
47 #define XBD_SEGS_TO_SIZE(segs) \
48 (((segs) - 1) * PAGE_SIZE)
51 * Compute the maximum number of blkif segments requried to represent
52 * an I/O of the given size.
54 * \note This calculation assumes that all but the first and last segments
55 * of the I/O are fully utilized.
57 * \note We reserve a segement to guarantee we can handle an unaligned
58 * transfer without the need to use a bounce buffer.
60 #define XBD_SIZE_TO_SEGS(size) \
61 ((size / PAGE_SIZE) + 1)
64 * The maximum number of shared memory ring pages we will allow in a
65 * negotiated block-front/back communication channel. Allow enough
66 * ring space for all requests to be XBD_MAX_REQUEST_SIZE'd.
68 #define XBD_MAX_RING_PAGES 32
71 * The maximum number of outstanding requests blocks (request headers plus
72 * additional segment blocks) we will allow in a negotiated block-front/back
73 * communication channel.
75 #define XBD_MAX_REQUESTS \
76 __CONST_RING_SIZE(blkif, PAGE_SIZE * XBD_MAX_RING_PAGES)
79 * The maximum mapped region size per request we will allow in a negotiated
80 * block-front/back communication channel.
82 #define XBD_MAX_REQUEST_SIZE \
83 MIN(MAXPHYS, XBD_SEGS_TO_SIZE(BLKIF_MAX_SEGMENTS_PER_REQUEST))
86 * The maximum number of segments (within a request header and accompanying
87 * segment blocks) per request we will allow in a negotiated block-front/back
88 * communication channel.
90 #define XBD_MAX_SEGMENTS_PER_REQUEST \
91 (MIN(BLKIF_MAX_SEGMENTS_PER_REQUEST, \
92 XBD_SIZE_TO_SEGS(XBD_MAX_REQUEST_SIZE)))
96 /* This command has contributed to xbd_qfrozen_cnt. */
98 /* Freeze the command queue on dispatch (i.e. single step command). */
99 XBDCF_Q_FREEZE = 1<<9,
100 /* Bus DMA returned EINPROGRESS for this command. */
101 XBDCF_ASYNC_MAPPING = 1<<10,
102 XBDCF_INITIALIZER = XBDCF_Q_MASK
106 typedef void xbd_cbcf_t(struct xbd_command *);
109 TAILQ_ENTRY(xbd_command) cm_link;
110 struct xbd_softc *cm_sc;
111 xbdc_flag_t cm_flags;
114 grant_ref_t *cm_sg_refs;
116 grant_ref_t cm_gref_head;
121 blkif_sector_t cm_sector_number;
123 xbd_cbcf_t *cm_complete;
133 XBD_Q_NONE = XBDCF_Q_MASK
136 typedef struct xbd_cm_q {
137 TAILQ_HEAD(, xbd_command) q_tailq;
143 XBD_STATE_DISCONNECTED,
150 XBDF_OPEN = 1 << 0, /* drive is open (can't shut down) */
151 XBDF_BARRIER = 1 << 1, /* backend supports barriers */
152 XBDF_FLUSH = 1 << 2, /* backend supports flush */
153 XBDF_READY = 1 << 3, /* Is ready */
154 XBDF_CM_SHORTAGE = 1 << 4, /* Free cm resource shortage active. */
155 XBDF_GNT_SHORTAGE = 1 << 5, /* Grant ref resource shortage active */
156 XBDF_WAIT_IDLE = 1 << 6 /*
157 * No new work until oustanding work
163 * We have one of these per vbd, whether ide, scsi or 'other'.
167 struct disk *xbd_disk; /* disk params */
168 struct bio_queue_head xbd_bioq; /* sort queue */
170 xbd_flag_t xbd_flags;
173 xbd_state_t xbd_state;
174 u_int xbd_ring_pages;
175 uint32_t xbd_max_requests;
176 uint32_t xbd_max_request_segments;
177 uint32_t xbd_max_request_size;
178 grant_ref_t xbd_ring_ref[XBD_MAX_RING_PAGES];
179 blkif_front_ring_t xbd_ring;
180 xen_intr_handle_t xen_intr_handle;
181 struct gnttab_free_callback xbd_callback;
182 xbd_cm_q_t xbd_cm_q[XBD_Q_COUNT];
183 bus_dma_tag_t xbd_io_dmat;
186 * The number of people holding this device open. We won't allow a
187 * hot-unplug unless this is 0.
190 struct mtx xbd_io_lock;
192 struct xbd_command *xbd_shadow;
195 int xbd_instance_create(struct xbd_softc *, blkif_sector_t sectors, int device,
196 uint16_t vdisk_info, unsigned long sector_size);
199 xbd_added_qentry(struct xbd_softc *sc, xbd_q_index_t index)
201 struct xbd_cm_q *cmq;
203 cmq = &sc->xbd_cm_q[index];
205 if (cmq->q_length > cmq->q_max)
206 cmq->q_max = cmq->q_length;
210 xbd_removed_qentry(struct xbd_softc *sc, xbd_q_index_t index)
212 sc->xbd_cm_q[index].q_length--;
215 static inline uint32_t
216 xbd_queue_length(struct xbd_softc *sc, xbd_q_index_t index)
218 return (sc->xbd_cm_q[index].q_length);
222 xbd_initq_cm(struct xbd_softc *sc, xbd_q_index_t index)
224 struct xbd_cm_q *cmq;
226 cmq = &sc->xbd_cm_q[index];
227 TAILQ_INIT(&cmq->q_tailq);
233 xbd_enqueue_cm(struct xbd_command *cm, xbd_q_index_t index)
235 KASSERT(index != XBD_Q_BIO,
236 ("%s: Commands cannot access the bio queue.", __func__));
237 if ((cm->cm_flags & XBDCF_Q_MASK) != XBD_Q_NONE)
238 panic("%s: command %p is already on queue %d.",
239 __func__, cm, cm->cm_flags & XBDCF_Q_MASK);
240 TAILQ_INSERT_TAIL(&cm->cm_sc->xbd_cm_q[index].q_tailq, cm, cm_link);
241 cm->cm_flags &= ~XBDCF_Q_MASK;
242 cm->cm_flags |= index;
243 xbd_added_qentry(cm->cm_sc, index);
247 xbd_requeue_cm(struct xbd_command *cm, xbd_q_index_t index)
249 KASSERT(index != XBD_Q_BIO,
250 ("%s: Commands cannot access the bio queue.", __func__));
251 if ((cm->cm_flags & XBDCF_Q_MASK) != XBD_Q_NONE)
252 panic("%s: command %p is already on queue %d.",
253 __func__, cm, cm->cm_flags & XBDCF_Q_MASK);
254 TAILQ_INSERT_HEAD(&cm->cm_sc->xbd_cm_q[index].q_tailq, cm, cm_link);
255 cm->cm_flags &= ~XBDCF_Q_MASK;
256 cm->cm_flags |= index;
257 xbd_added_qentry(cm->cm_sc, index);
260 static inline struct xbd_command *
261 xbd_dequeue_cm(struct xbd_softc *sc, xbd_q_index_t index)
263 struct xbd_command *cm;
265 KASSERT(index != XBD_Q_BIO,
266 ("%s: Commands cannot access the bio queue.", __func__));
268 if ((cm = TAILQ_FIRST(&sc->xbd_cm_q[index].q_tailq)) != NULL) {
269 if ((cm->cm_flags & XBDCF_Q_MASK) != index) {
270 panic("%s: command %p is on queue %d, "
271 "not specified queue %d",
273 cm->cm_flags & XBDCF_Q_MASK,
276 TAILQ_REMOVE(&sc->xbd_cm_q[index].q_tailq, cm, cm_link);
277 cm->cm_flags &= ~XBDCF_Q_MASK;
278 cm->cm_flags |= XBD_Q_NONE;
279 xbd_removed_qentry(cm->cm_sc, index);
285 xbd_remove_cm(struct xbd_command *cm, xbd_q_index_t expected_index)
289 index = cm->cm_flags & XBDCF_Q_MASK;
291 KASSERT(index != XBD_Q_BIO,
292 ("%s: Commands cannot access the bio queue.", __func__));
294 if (index != expected_index) {
295 panic("%s: command %p is on queue %d, not specified queue %d",
296 __func__, cm, index, expected_index);
298 TAILQ_REMOVE(&cm->cm_sc->xbd_cm_q[index].q_tailq, cm, cm_link);
299 cm->cm_flags &= ~XBDCF_Q_MASK;
300 cm->cm_flags |= XBD_Q_NONE;
301 xbd_removed_qentry(cm->cm_sc, index);
305 xbd_initq_bio(struct xbd_softc *sc)
307 bioq_init(&sc->xbd_bioq);
311 xbd_enqueue_bio(struct xbd_softc *sc, struct bio *bp)
313 bioq_insert_tail(&sc->xbd_bioq, bp);
314 xbd_added_qentry(sc, XBD_Q_BIO);
318 xbd_requeue_bio(struct xbd_softc *sc, struct bio *bp)
320 bioq_insert_head(&sc->xbd_bioq, bp);
321 xbd_added_qentry(sc, XBD_Q_BIO);
324 static inline struct bio *
325 xbd_dequeue_bio(struct xbd_softc *sc)
329 if ((bp = bioq_first(&sc->xbd_bioq)) != NULL) {
330 bioq_remove(&sc->xbd_bioq, bp);
331 xbd_removed_qentry(sc, XBD_Q_BIO);
337 xbd_initqs(struct xbd_softc *sc)
341 for (index = 0; index < XBD_Q_COUNT; index++)
342 xbd_initq_cm(sc, index);
347 #endif /* __XEN_BLKFRONT_BLOCK_H__ */