1 /* 2 * XenBSD block device driver 3 * 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 11 * 12 * 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: 19 * 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. 29 * 30 * $FreeBSD$ 31 */ 32 33 #ifndef __XEN_BLKFRONT_BLOCK_H__ 34 #define __XEN_BLKFRONT_BLOCK_H__ 35 #include <xen/blkif.h> 36 37 /** 38 * Given a number of blkif segments, compute the maximum I/O size supported. 39 * 40 * \note This calculation assumes that all but the first and last segments 41 * of the I/O are fully utilized. 42 * 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. 46 */ 47 #define XBD_SEGS_TO_SIZE(segs) \ 48 (((segs) - 1) * PAGE_SIZE) 49 50 /** 51 * Compute the maximum number of blkif segments requried to represent 52 * an I/O of the given size. 53 * 54 * \note This calculation assumes that all but the first and last segments 55 * of the I/O are fully utilized. 56 * 57 * \note We reserve a segement to guarantee we can handle an unaligned 58 * transfer without the need to use a bounce buffer. 59 */ 60 #define XBD_SIZE_TO_SEGS(size) \ 61 ((size / PAGE_SIZE) + 1) 62 63 /** 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. 67 */ 68 #define XBD_MAX_RING_PAGES 32 69 70 /** 71 * The maximum number of outstanding requests we will allow in a negotiated 72 * block-front/back communication channel. 73 */ 74 #define XBD_MAX_REQUESTS \ 75 __CONST_RING_SIZE(blkif, PAGE_SIZE * XBD_MAX_RING_PAGES) 76 77 /** 78 * The maximum number of blkif segments which can be provided per indirect 79 * page in an indirect request. 80 */ 81 #define XBD_MAX_SEGMENTS_PER_PAGE \ 82 (PAGE_SIZE / sizeof(struct blkif_request_segment)) 83 84 /** 85 * The maximum number of blkif segments which can be provided in an indirect 86 * request. 87 */ 88 #define XBD_MAX_INDIRECT_SEGMENTS \ 89 (BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST * XBD_MAX_SEGMENTS_PER_PAGE) 90 91 /** 92 * Compute the number of indirect segment pages required for an I/O with the 93 * specified number of indirect segments. 94 */ 95 #define XBD_INDIRECT_SEGS_TO_PAGES(segs) \ 96 ((segs + XBD_MAX_SEGMENTS_PER_PAGE - 1) / XBD_MAX_SEGMENTS_PER_PAGE) 97 98 typedef enum { 99 XBDCF_Q_MASK = 0xFF, 100 /* This command has contributed to xbd_qfrozen_cnt. */ 101 XBDCF_FROZEN = 1<<8, 102 /* Freeze the command queue on dispatch (i.e. single step command). */ 103 XBDCF_Q_FREEZE = 1<<9, 104 /* Bus DMA returned EINPROGRESS for this command. */ 105 XBDCF_ASYNC_MAPPING = 1<<10, 106 XBDCF_INITIALIZER = XBDCF_Q_MASK 107 } xbdc_flag_t; 108 109 struct xbd_command; 110 typedef void xbd_cbcf_t(struct xbd_command *); 111 112 struct xbd_command { 113 TAILQ_ENTRY(xbd_command) cm_link; 114 struct xbd_softc *cm_sc; 115 xbdc_flag_t cm_flags; 116 bus_dmamap_t cm_map; 117 uint64_t cm_id; 118 grant_ref_t *cm_sg_refs; 119 struct bio *cm_bp; 120 grant_ref_t cm_gref_head; 121 void *cm_data; 122 size_t cm_datalen; 123 u_int cm_nseg; 124 int cm_operation; 125 blkif_sector_t cm_sector_number; 126 int cm_status; 127 xbd_cbcf_t *cm_complete; 128 void *cm_indirectionpages; 129 grant_ref_t cm_indirectionrefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST]; 130 }; 131 132 typedef enum { 133 XBD_Q_FREE, 134 XBD_Q_READY, 135 XBD_Q_BUSY, 136 XBD_Q_COMPLETE, 137 XBD_Q_BIO, 138 XBD_Q_COUNT, 139 XBD_Q_NONE = XBDCF_Q_MASK 140 } xbd_q_index_t; 141 142 typedef struct xbd_cm_q { 143 TAILQ_HEAD(, xbd_command) q_tailq; 144 uint32_t q_length; 145 uint32_t q_max; 146 } xbd_cm_q_t; 147 148 typedef enum { 149 XBD_STATE_DISCONNECTED, 150 XBD_STATE_CONNECTED, 151 XBD_STATE_SUSPENDED 152 } xbd_state_t; 153 154 typedef enum { 155 XBDF_NONE = 0, 156 XBDF_OPEN = 1 << 0, /* drive is open (can't shut down) */ 157 XBDF_BARRIER = 1 << 1, /* backend supports barriers */ 158 XBDF_FLUSH = 1 << 2, /* backend supports flush */ 159 XBDF_READY = 1 << 3, /* Is ready */ 160 XBDF_CM_SHORTAGE = 1 << 4, /* Free cm resource shortage active. */ 161 XBDF_GNT_SHORTAGE = 1 << 5, /* Grant ref resource shortage active */ 162 XBDF_WAIT_IDLE = 1 << 6, /* 163 * No new work until outstanding work 164 * completes. 165 */ 166 XBDF_DISCARD = 1 << 7, /* backend supports discard */ 167 XBDF_PERSISTENT = 1 << 8 /* backend supports persistent grants */ 168 } xbd_flag_t; 169 170 /* 171 * We have one of these per vbd, whether ide, scsi or 'other'. 172 */ 173 struct xbd_softc { 174 device_t xbd_dev; 175 struct disk *xbd_disk; /* disk params */ 176 struct bio_queue_head xbd_bioq; /* sort queue */ 177 int xbd_unit; 178 xbd_flag_t xbd_flags; 179 int xbd_qfrozen_cnt; 180 int xbd_vdevice; 181 xbd_state_t xbd_state; 182 u_int xbd_ring_pages; 183 uint32_t xbd_max_requests; 184 uint32_t xbd_max_request_segments; 185 uint32_t xbd_max_request_size; 186 uint32_t xbd_max_request_indirectpages; 187 grant_ref_t xbd_ring_ref[XBD_MAX_RING_PAGES]; 188 blkif_front_ring_t xbd_ring; 189 xen_intr_handle_t xen_intr_handle; 190 struct gnttab_free_callback xbd_callback; 191 xbd_cm_q_t xbd_cm_q[XBD_Q_COUNT]; 192 bus_dma_tag_t xbd_io_dmat; 193 194 /** 195 * The number of people holding this device open. We won't allow a 196 * hot-unplug unless this is 0. 197 */ 198 int xbd_users; 199 struct mtx xbd_io_lock; 200 201 struct xbd_command *xbd_shadow; 202 }; 203 204 int xbd_instance_create(struct xbd_softc *, blkif_sector_t sectors, int device, 205 uint16_t vdisk_info, unsigned long sector_size, 206 unsigned long phys_sector_size); 207 208 static inline void 209 xbd_added_qentry(struct xbd_softc *sc, xbd_q_index_t index) 210 { 211 struct xbd_cm_q *cmq; 212 213 cmq = &sc->xbd_cm_q[index]; 214 cmq->q_length++; 215 if (cmq->q_length > cmq->q_max) 216 cmq->q_max = cmq->q_length; 217 } 218 219 static inline void 220 xbd_removed_qentry(struct xbd_softc *sc, xbd_q_index_t index) 221 { 222 sc->xbd_cm_q[index].q_length--; 223 } 224 225 static inline uint32_t 226 xbd_queue_length(struct xbd_softc *sc, xbd_q_index_t index) 227 { 228 return (sc->xbd_cm_q[index].q_length); 229 } 230 231 static inline void 232 xbd_initq_cm(struct xbd_softc *sc, xbd_q_index_t index) 233 { 234 struct xbd_cm_q *cmq; 235 236 cmq = &sc->xbd_cm_q[index]; 237 TAILQ_INIT(&cmq->q_tailq); 238 cmq->q_length = 0; 239 cmq->q_max = 0; 240 } 241 242 static inline void 243 xbd_enqueue_cm(struct xbd_command *cm, xbd_q_index_t index) 244 { 245 KASSERT(index != XBD_Q_BIO, 246 ("%s: Commands cannot access the bio queue.", __func__)); 247 if ((cm->cm_flags & XBDCF_Q_MASK) != XBD_Q_NONE) 248 panic("%s: command %p is already on queue %d.", 249 __func__, cm, cm->cm_flags & XBDCF_Q_MASK); 250 TAILQ_INSERT_TAIL(&cm->cm_sc->xbd_cm_q[index].q_tailq, cm, cm_link); 251 cm->cm_flags &= ~XBDCF_Q_MASK; 252 cm->cm_flags |= index; 253 xbd_added_qentry(cm->cm_sc, index); 254 } 255 256 static inline void 257 xbd_requeue_cm(struct xbd_command *cm, xbd_q_index_t index) 258 { 259 KASSERT(index != XBD_Q_BIO, 260 ("%s: Commands cannot access the bio queue.", __func__)); 261 if ((cm->cm_flags & XBDCF_Q_MASK) != XBD_Q_NONE) 262 panic("%s: command %p is already on queue %d.", 263 __func__, cm, cm->cm_flags & XBDCF_Q_MASK); 264 TAILQ_INSERT_HEAD(&cm->cm_sc->xbd_cm_q[index].q_tailq, cm, cm_link); 265 cm->cm_flags &= ~XBDCF_Q_MASK; 266 cm->cm_flags |= index; 267 xbd_added_qentry(cm->cm_sc, index); 268 } 269 270 static inline struct xbd_command * 271 xbd_dequeue_cm(struct xbd_softc *sc, xbd_q_index_t index) 272 { 273 struct xbd_command *cm; 274 275 KASSERT(index != XBD_Q_BIO, 276 ("%s: Commands cannot access the bio queue.", __func__)); 277 278 if ((cm = TAILQ_FIRST(&sc->xbd_cm_q[index].q_tailq)) != NULL) { 279 if ((cm->cm_flags & XBDCF_Q_MASK) != index) { 280 panic("%s: command %p is on queue %d, " 281 "not specified queue %d", 282 __func__, cm, 283 cm->cm_flags & XBDCF_Q_MASK, 284 index); 285 } 286 TAILQ_REMOVE(&sc->xbd_cm_q[index].q_tailq, cm, cm_link); 287 cm->cm_flags &= ~XBDCF_Q_MASK; 288 cm->cm_flags |= XBD_Q_NONE; 289 xbd_removed_qentry(cm->cm_sc, index); 290 } 291 return (cm); 292 } 293 294 static inline void 295 xbd_remove_cm(struct xbd_command *cm, xbd_q_index_t expected_index) 296 { 297 xbd_q_index_t index; 298 299 index = cm->cm_flags & XBDCF_Q_MASK; 300 301 KASSERT(index != XBD_Q_BIO, 302 ("%s: Commands cannot access the bio queue.", __func__)); 303 304 if (index != expected_index) { 305 panic("%s: command %p is on queue %d, not specified queue %d", 306 __func__, cm, index, expected_index); 307 } 308 TAILQ_REMOVE(&cm->cm_sc->xbd_cm_q[index].q_tailq, cm, cm_link); 309 cm->cm_flags &= ~XBDCF_Q_MASK; 310 cm->cm_flags |= XBD_Q_NONE; 311 xbd_removed_qentry(cm->cm_sc, index); 312 } 313 314 static inline void 315 xbd_initq_bio(struct xbd_softc *sc) 316 { 317 bioq_init(&sc->xbd_bioq); 318 } 319 320 static inline void 321 xbd_enqueue_bio(struct xbd_softc *sc, struct bio *bp) 322 { 323 bioq_insert_tail(&sc->xbd_bioq, bp); 324 xbd_added_qentry(sc, XBD_Q_BIO); 325 } 326 327 static inline void 328 xbd_requeue_bio(struct xbd_softc *sc, struct bio *bp) 329 { 330 bioq_insert_head(&sc->xbd_bioq, bp); 331 xbd_added_qentry(sc, XBD_Q_BIO); 332 } 333 334 static inline struct bio * 335 xbd_dequeue_bio(struct xbd_softc *sc) 336 { 337 struct bio *bp; 338 339 if ((bp = bioq_first(&sc->xbd_bioq)) != NULL) { 340 bioq_remove(&sc->xbd_bioq, bp); 341 xbd_removed_qentry(sc, XBD_Q_BIO); 342 } 343 return (bp); 344 } 345 346 static inline void 347 xbd_initqs(struct xbd_softc *sc) 348 { 349 u_int index; 350 351 for (index = 0; index < XBD_Q_COUNT; index++) 352 xbd_initq_cm(sc, index); 353 354 xbd_initq_bio(sc); 355 } 356 357 #endif /* __XEN_BLKFRONT_BLOCK_H__ */ 358