123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957958959960961962963964965966967968969970971972973974975976977978979980981982983984985986987988989990991992993994995996997998999100010011002100310041005100610071008100910101011101210131014101510161017101810191020102110221023102410251026102710281029103010311032103310341035103610371038103910401041104210431044104510461047104810491050105110521053105410551056105710581059106010611062106310641065106610671068106910701071107210731074107510761077107810791080108110821083108410851086108710881089109010911092109310941095109610971098109911001101110211031104110511061107110811091110111111121113111411151116111711181119112011211122112311241125112611271128112911301131113211331134113511361137113811391140114111421143114411451146114711481149115011511152115311541155115611571158115911601161116211631164116511661167116811691170117111721173117411751176117711781179118011811182118311841185118611871188118911901191119211931194119511961197119811991200120112021203120412051206120712081209121012111212121312141215121612171218121912201221122212231224122512261227122812291230123112321233123412351236123712381239 |
- /*
- * Xen SCSI frontend driver
- *
- * Copyright (c) 2008, FUJITSU Limited
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License version 2
- * as published by the Free Software Foundation; or, when distributed
- * separately from the Linux kernel or incorporated into other
- * software packages, subject to the following license:
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this source file (the "Software"), to deal in the Software without
- * restriction, including without limitation the rights to use, copy, modify,
- * merge, publish, distribute, sublicense, and/or sell copies of the Software,
- * and to permit persons to whom the Software is furnished to do so, subject to
- * the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
- * IN THE SOFTWARE.
- */
- #include <linux/module.h>
- #include <linux/kernel.h>
- #include <linux/device.h>
- #include <linux/wait.h>
- #include <linux/interrupt.h>
- #include <linux/mutex.h>
- #include <linux/spinlock.h>
- #include <linux/sched.h>
- #include <linux/blkdev.h>
- #include <linux/pfn.h>
- #include <linux/slab.h>
- #include <linux/bitops.h>
- #include <scsi/scsi_cmnd.h>
- #include <scsi/scsi_device.h>
- #include <scsi/scsi.h>
- #include <scsi/scsi_host.h>
- #include <xen/xen.h>
- #include <xen/xenbus.h>
- #include <xen/grant_table.h>
- #include <xen/events.h>
- #include <xen/page.h>
- #include <xen/interface/grant_table.h>
- #include <xen/interface/io/vscsiif.h>
- #include <xen/interface/io/protocols.h>
- #include <asm/xen/hypervisor.h>
- #define VSCSIFRONT_OP_ADD_LUN 1
- #define VSCSIFRONT_OP_DEL_LUN 2
- #define VSCSIFRONT_OP_READD_LUN 3
- /* Tuning point. */
- #define VSCSIIF_DEFAULT_CMD_PER_LUN 10
- #define VSCSIIF_MAX_TARGET 64
- #define VSCSIIF_MAX_LUN 255
- #define VSCSIIF_RING_SIZE __CONST_RING_SIZE(vscsiif, PAGE_SIZE)
- #define VSCSIIF_MAX_REQS VSCSIIF_RING_SIZE
- #define vscsiif_grants_sg(_sg) (PFN_UP((_sg) * \
- sizeof(struct scsiif_request_segment)))
- struct vscsifrnt_shadow {
- /* command between backend and frontend */
- unsigned char act;
- uint8_t nr_segments;
- uint16_t rqid;
- uint16_t ref_rqid;
- bool inflight;
- unsigned int nr_grants; /* number of grants in gref[] */
- struct scsiif_request_segment *sg; /* scatter/gather elements */
- struct scsiif_request_segment seg[VSCSIIF_SG_TABLESIZE];
- /* Do reset or abort function. */
- wait_queue_head_t wq_reset; /* reset work queue */
- int wait_reset; /* reset work queue condition */
- int32_t rslt_reset; /* reset response status: */
- /* SUCCESS or FAILED or: */
- #define RSLT_RESET_WAITING 0
- #define RSLT_RESET_ERR -1
- /* Requested struct scsi_cmnd is stored from kernel. */
- struct scsi_cmnd *sc;
- int gref[vscsiif_grants_sg(SG_ALL) + SG_ALL];
- };
- struct vscsifrnt_info {
- struct xenbus_device *dev;
- struct Scsi_Host *host;
- enum {
- STATE_INACTIVE,
- STATE_ACTIVE,
- STATE_ERROR
- } host_active;
- unsigned int evtchn;
- unsigned int irq;
- grant_ref_t ring_ref;
- struct vscsiif_front_ring ring;
- struct vscsiif_response ring_rsp;
- spinlock_t shadow_lock;
- DECLARE_BITMAP(shadow_free_bitmap, VSCSIIF_MAX_REQS);
- struct vscsifrnt_shadow *shadow[VSCSIIF_MAX_REQS];
- /* Following items are protected by the host lock. */
- wait_queue_head_t wq_sync;
- wait_queue_head_t wq_pause;
- unsigned int wait_ring_available:1;
- unsigned int waiting_pause:1;
- unsigned int pause:1;
- unsigned callers;
- char dev_state_path[64];
- struct task_struct *curr;
- };
- static DEFINE_MUTEX(scsifront_mutex);
- static void scsifront_wake_up(struct vscsifrnt_info *info)
- {
- info->wait_ring_available = 0;
- wake_up(&info->wq_sync);
- }
- static int scsifront_get_rqid(struct vscsifrnt_info *info)
- {
- unsigned long flags;
- int free;
- spin_lock_irqsave(&info->shadow_lock, flags);
- free = find_first_bit(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
- __clear_bit(free, info->shadow_free_bitmap);
- spin_unlock_irqrestore(&info->shadow_lock, flags);
- return free;
- }
- static int _scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id)
- {
- int empty = bitmap_empty(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
- __set_bit(id, info->shadow_free_bitmap);
- info->shadow[id] = NULL;
- return empty || info->wait_ring_available;
- }
- static void scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id)
- {
- unsigned long flags;
- int kick;
- spin_lock_irqsave(&info->shadow_lock, flags);
- kick = _scsifront_put_rqid(info, id);
- spin_unlock_irqrestore(&info->shadow_lock, flags);
- if (kick)
- scsifront_wake_up(info);
- }
- static int scsifront_do_request(struct vscsifrnt_info *info,
- struct vscsifrnt_shadow *shadow)
- {
- struct vscsiif_front_ring *ring = &(info->ring);
- struct vscsiif_request *ring_req;
- struct scsi_cmnd *sc = shadow->sc;
- uint32_t id;
- int i, notify;
- if (RING_FULL(&info->ring))
- return -EBUSY;
- id = scsifront_get_rqid(info); /* use id in response */
- if (id >= VSCSIIF_MAX_REQS)
- return -EBUSY;
- info->shadow[id] = shadow;
- shadow->rqid = id;
- ring_req = RING_GET_REQUEST(&(info->ring), ring->req_prod_pvt);
- ring->req_prod_pvt++;
- ring_req->rqid = id;
- ring_req->act = shadow->act;
- ring_req->ref_rqid = shadow->ref_rqid;
- ring_req->nr_segments = shadow->nr_segments;
- ring_req->id = sc->device->id;
- ring_req->lun = sc->device->lun;
- ring_req->channel = sc->device->channel;
- ring_req->cmd_len = sc->cmd_len;
- BUG_ON(sc->cmd_len > VSCSIIF_MAX_COMMAND_SIZE);
- memcpy(ring_req->cmnd, sc->cmnd, sc->cmd_len);
- ring_req->sc_data_direction = (uint8_t)sc->sc_data_direction;
- ring_req->timeout_per_command = scsi_cmd_to_rq(sc)->timeout / HZ;
- for (i = 0; i < (shadow->nr_segments & ~VSCSIIF_SG_GRANT); i++)
- ring_req->seg[i] = shadow->seg[i];
- shadow->inflight = true;
- RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(ring, notify);
- if (notify)
- notify_remote_via_irq(info->irq);
- return 0;
- }
- static void scsifront_set_error(struct vscsifrnt_info *info, const char *msg)
- {
- shost_printk(KERN_ERR, info->host, KBUILD_MODNAME "%s\n"
- "Disabling device for further use\n", msg);
- info->host_active = STATE_ERROR;
- }
- static void scsifront_gnttab_done(struct vscsifrnt_info *info,
- struct vscsifrnt_shadow *shadow)
- {
- int i;
- if (shadow->sc->sc_data_direction == DMA_NONE)
- return;
- for (i = 0; i < shadow->nr_grants; i++) {
- if (unlikely(!gnttab_try_end_foreign_access(shadow->gref[i]))) {
- scsifront_set_error(info, "grant still in use by backend");
- return;
- }
- }
- kfree(shadow->sg);
- }
- static unsigned int scsifront_host_byte(int32_t rslt)
- {
- switch (XEN_VSCSIIF_RSLT_HOST(rslt)) {
- case XEN_VSCSIIF_RSLT_HOST_OK:
- return DID_OK;
- case XEN_VSCSIIF_RSLT_HOST_NO_CONNECT:
- return DID_NO_CONNECT;
- case XEN_VSCSIIF_RSLT_HOST_BUS_BUSY:
- return DID_BUS_BUSY;
- case XEN_VSCSIIF_RSLT_HOST_TIME_OUT:
- return DID_TIME_OUT;
- case XEN_VSCSIIF_RSLT_HOST_BAD_TARGET:
- return DID_BAD_TARGET;
- case XEN_VSCSIIF_RSLT_HOST_ABORT:
- return DID_ABORT;
- case XEN_VSCSIIF_RSLT_HOST_PARITY:
- return DID_PARITY;
- case XEN_VSCSIIF_RSLT_HOST_ERROR:
- return DID_ERROR;
- case XEN_VSCSIIF_RSLT_HOST_RESET:
- return DID_RESET;
- case XEN_VSCSIIF_RSLT_HOST_BAD_INTR:
- return DID_BAD_INTR;
- case XEN_VSCSIIF_RSLT_HOST_PASSTHROUGH:
- return DID_PASSTHROUGH;
- case XEN_VSCSIIF_RSLT_HOST_SOFT_ERROR:
- return DID_SOFT_ERROR;
- case XEN_VSCSIIF_RSLT_HOST_IMM_RETRY:
- return DID_IMM_RETRY;
- case XEN_VSCSIIF_RSLT_HOST_REQUEUE:
- return DID_REQUEUE;
- case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_DISRUPTED:
- return DID_TRANSPORT_DISRUPTED;
- case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_FAILFAST:
- return DID_TRANSPORT_FAILFAST;
- case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_MARGINAL:
- return DID_TRANSPORT_MARGINAL;
- default:
- return DID_ERROR;
- }
- }
- static void scsifront_cdb_cmd_done(struct vscsifrnt_info *info,
- struct vscsiif_response *ring_rsp)
- {
- struct vscsifrnt_shadow *shadow;
- struct scsi_cmnd *sc;
- uint32_t id;
- uint8_t sense_len;
- id = ring_rsp->rqid;
- shadow = info->shadow[id];
- sc = shadow->sc;
- BUG_ON(sc == NULL);
- scsifront_gnttab_done(info, shadow);
- if (info->host_active == STATE_ERROR)
- return;
- scsifront_put_rqid(info, id);
- set_host_byte(sc, scsifront_host_byte(ring_rsp->rslt));
- set_status_byte(sc, XEN_VSCSIIF_RSLT_STATUS(ring_rsp->rslt));
- scsi_set_resid(sc, ring_rsp->residual_len);
- sense_len = min_t(uint8_t, VSCSIIF_SENSE_BUFFERSIZE,
- ring_rsp->sense_len);
- if (sense_len)
- memcpy(sc->sense_buffer, ring_rsp->sense_buffer, sense_len);
- scsi_done(sc);
- }
- static void scsifront_sync_cmd_done(struct vscsifrnt_info *info,
- struct vscsiif_response *ring_rsp)
- {
- uint16_t id = ring_rsp->rqid;
- unsigned long flags;
- struct vscsifrnt_shadow *shadow = info->shadow[id];
- int kick;
- spin_lock_irqsave(&info->shadow_lock, flags);
- shadow->wait_reset = 1;
- switch (shadow->rslt_reset) {
- case RSLT_RESET_WAITING:
- if (ring_rsp->rslt == XEN_VSCSIIF_RSLT_RESET_SUCCESS)
- shadow->rslt_reset = SUCCESS;
- else
- shadow->rslt_reset = FAILED;
- break;
- case RSLT_RESET_ERR:
- kick = _scsifront_put_rqid(info, id);
- spin_unlock_irqrestore(&info->shadow_lock, flags);
- kfree(shadow);
- if (kick)
- scsifront_wake_up(info);
- return;
- default:
- scsifront_set_error(info, "bad reset state");
- break;
- }
- spin_unlock_irqrestore(&info->shadow_lock, flags);
- wake_up(&shadow->wq_reset);
- }
- static void scsifront_do_response(struct vscsifrnt_info *info,
- struct vscsiif_response *ring_rsp)
- {
- struct vscsifrnt_shadow *shadow;
- if (ring_rsp->rqid >= VSCSIIF_MAX_REQS ||
- !info->shadow[ring_rsp->rqid]->inflight) {
- scsifront_set_error(info, "illegal rqid returned by backend!");
- return;
- }
- shadow = info->shadow[ring_rsp->rqid];
- shadow->inflight = false;
- if (shadow->act == VSCSIIF_ACT_SCSI_CDB)
- scsifront_cdb_cmd_done(info, ring_rsp);
- else
- scsifront_sync_cmd_done(info, ring_rsp);
- }
- static int scsifront_ring_drain(struct vscsifrnt_info *info,
- unsigned int *eoiflag)
- {
- struct vscsiif_response ring_rsp;
- RING_IDX i, rp;
- int more_to_do = 0;
- rp = READ_ONCE(info->ring.sring->rsp_prod);
- virt_rmb(); /* ordering required respective to backend */
- if (RING_RESPONSE_PROD_OVERFLOW(&info->ring, rp)) {
- scsifront_set_error(info, "illegal number of responses");
- return 0;
- }
- for (i = info->ring.rsp_cons; i != rp; i++) {
- RING_COPY_RESPONSE(&info->ring, i, &ring_rsp);
- scsifront_do_response(info, &ring_rsp);
- if (info->host_active == STATE_ERROR)
- return 0;
- *eoiflag &= ~XEN_EOI_FLAG_SPURIOUS;
- }
- info->ring.rsp_cons = i;
- if (i != info->ring.req_prod_pvt)
- RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
- else
- info->ring.sring->rsp_event = i + 1;
- return more_to_do;
- }
- static int scsifront_cmd_done(struct vscsifrnt_info *info,
- unsigned int *eoiflag)
- {
- int more_to_do;
- unsigned long flags;
- spin_lock_irqsave(info->host->host_lock, flags);
- more_to_do = scsifront_ring_drain(info, eoiflag);
- info->wait_ring_available = 0;
- spin_unlock_irqrestore(info->host->host_lock, flags);
- wake_up(&info->wq_sync);
- return more_to_do;
- }
- static irqreturn_t scsifront_irq_fn(int irq, void *dev_id)
- {
- struct vscsifrnt_info *info = dev_id;
- unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS;
- if (info->host_active == STATE_ERROR) {
- xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
- return IRQ_HANDLED;
- }
- while (scsifront_cmd_done(info, &eoiflag))
- /* Yield point for this unbounded loop. */
- cond_resched();
- xen_irq_lateeoi(irq, eoiflag);
- return IRQ_HANDLED;
- }
- static void scsifront_finish_all(struct vscsifrnt_info *info)
- {
- unsigned int i, dummy;
- struct vscsiif_response resp;
- scsifront_ring_drain(info, &dummy);
- for (i = 0; i < VSCSIIF_MAX_REQS; i++) {
- if (test_bit(i, info->shadow_free_bitmap))
- continue;
- resp.rqid = i;
- resp.sense_len = 0;
- resp.rslt = DID_RESET << 16;
- resp.residual_len = 0;
- scsifront_do_response(info, &resp);
- }
- }
- static int map_data_for_request(struct vscsifrnt_info *info,
- struct scsi_cmnd *sc,
- struct vscsifrnt_shadow *shadow)
- {
- grant_ref_t gref_head;
- struct page *page;
- int err, ref, ref_cnt = 0;
- int grant_ro = (sc->sc_data_direction == DMA_TO_DEVICE);
- unsigned int i, off, len, bytes;
- unsigned int data_len = scsi_bufflen(sc);
- unsigned int data_grants = 0, seg_grants = 0;
- struct scatterlist *sg;
- struct scsiif_request_segment *seg;
- if (sc->sc_data_direction == DMA_NONE || !data_len)
- return 0;
- scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i)
- data_grants += PFN_UP(sg->offset + sg->length);
- if (data_grants > VSCSIIF_SG_TABLESIZE) {
- if (data_grants > info->host->sg_tablesize) {
- shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
- "Unable to map request_buffer for command!\n");
- return -E2BIG;
- }
- seg_grants = vscsiif_grants_sg(data_grants);
- shadow->sg = kcalloc(data_grants,
- sizeof(struct scsiif_request_segment), GFP_ATOMIC);
- if (!shadow->sg)
- return -ENOMEM;
- }
- seg = shadow->sg ? : shadow->seg;
- err = gnttab_alloc_grant_references(seg_grants + data_grants,
- &gref_head);
- if (err) {
- kfree(shadow->sg);
- shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
- "gnttab_alloc_grant_references() error\n");
- return -ENOMEM;
- }
- if (seg_grants) {
- page = virt_to_page(seg);
- off = offset_in_page(seg);
- len = sizeof(struct scsiif_request_segment) * data_grants;
- while (len > 0) {
- bytes = min_t(unsigned int, len, PAGE_SIZE - off);
- ref = gnttab_claim_grant_reference(&gref_head);
- BUG_ON(ref == -ENOSPC);
- gnttab_grant_foreign_access_ref(ref,
- info->dev->otherend_id,
- xen_page_to_gfn(page), 1);
- shadow->gref[ref_cnt] = ref;
- shadow->seg[ref_cnt].gref = ref;
- shadow->seg[ref_cnt].offset = (uint16_t)off;
- shadow->seg[ref_cnt].length = (uint16_t)bytes;
- page++;
- len -= bytes;
- off = 0;
- ref_cnt++;
- }
- BUG_ON(seg_grants < ref_cnt);
- seg_grants = ref_cnt;
- }
- scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i) {
- page = sg_page(sg);
- off = sg->offset;
- len = sg->length;
- while (len > 0 && data_len > 0) {
- /*
- * sg sends a scatterlist that is larger than
- * the data_len it wants transferred for certain
- * IO sizes.
- */
- bytes = min_t(unsigned int, len, PAGE_SIZE - off);
- bytes = min(bytes, data_len);
- ref = gnttab_claim_grant_reference(&gref_head);
- BUG_ON(ref == -ENOSPC);
- gnttab_grant_foreign_access_ref(ref,
- info->dev->otherend_id,
- xen_page_to_gfn(page),
- grant_ro);
- shadow->gref[ref_cnt] = ref;
- seg->gref = ref;
- seg->offset = (uint16_t)off;
- seg->length = (uint16_t)bytes;
- page++;
- seg++;
- len -= bytes;
- data_len -= bytes;
- off = 0;
- ref_cnt++;
- }
- }
- if (seg_grants)
- shadow->nr_segments = VSCSIIF_SG_GRANT | seg_grants;
- else
- shadow->nr_segments = (uint8_t)ref_cnt;
- shadow->nr_grants = ref_cnt;
- return 0;
- }
- static int scsifront_enter(struct vscsifrnt_info *info)
- {
- if (info->pause)
- return 1;
- info->callers++;
- return 0;
- }
- static void scsifront_return(struct vscsifrnt_info *info)
- {
- info->callers--;
- if (info->callers)
- return;
- if (!info->waiting_pause)
- return;
- info->waiting_pause = 0;
- wake_up(&info->wq_pause);
- }
- static int scsifront_queuecommand(struct Scsi_Host *shost,
- struct scsi_cmnd *sc)
- {
- struct vscsifrnt_info *info = shost_priv(shost);
- struct vscsifrnt_shadow *shadow = scsi_cmd_priv(sc);
- unsigned long flags;
- int err;
- if (info->host_active == STATE_ERROR)
- return SCSI_MLQUEUE_HOST_BUSY;
- sc->result = 0;
- shadow->sc = sc;
- shadow->act = VSCSIIF_ACT_SCSI_CDB;
- spin_lock_irqsave(shost->host_lock, flags);
- if (scsifront_enter(info)) {
- spin_unlock_irqrestore(shost->host_lock, flags);
- return SCSI_MLQUEUE_HOST_BUSY;
- }
- err = map_data_for_request(info, sc, shadow);
- if (err < 0) {
- pr_debug("%s: err %d\n", __func__, err);
- scsifront_return(info);
- spin_unlock_irqrestore(shost->host_lock, flags);
- if (err == -ENOMEM)
- return SCSI_MLQUEUE_HOST_BUSY;
- sc->result = DID_ERROR << 16;
- scsi_done(sc);
- return 0;
- }
- if (scsifront_do_request(info, shadow)) {
- scsifront_gnttab_done(info, shadow);
- goto busy;
- }
- scsifront_return(info);
- spin_unlock_irqrestore(shost->host_lock, flags);
- return 0;
- busy:
- scsifront_return(info);
- spin_unlock_irqrestore(shost->host_lock, flags);
- pr_debug("%s: busy\n", __func__);
- return SCSI_MLQUEUE_HOST_BUSY;
- }
- /*
- * Any exception handling (reset or abort) must be forwarded to the backend.
- * We have to wait until an answer is returned. This answer contains the
- * result to be returned to the requestor.
- */
- static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act)
- {
- struct Scsi_Host *host = sc->device->host;
- struct vscsifrnt_info *info = shost_priv(host);
- struct vscsifrnt_shadow *shadow, *s = scsi_cmd_priv(sc);
- int err = 0;
- if (info->host_active == STATE_ERROR)
- return FAILED;
- shadow = kzalloc(sizeof(*shadow), GFP_NOIO);
- if (!shadow)
- return FAILED;
- shadow->act = act;
- shadow->rslt_reset = RSLT_RESET_WAITING;
- shadow->sc = sc;
- shadow->ref_rqid = s->rqid;
- init_waitqueue_head(&shadow->wq_reset);
- spin_lock_irq(host->host_lock);
- for (;;) {
- if (scsifront_enter(info))
- goto fail;
- if (!scsifront_do_request(info, shadow))
- break;
- scsifront_return(info);
- if (err)
- goto fail;
- info->wait_ring_available = 1;
- spin_unlock_irq(host->host_lock);
- err = wait_event_interruptible(info->wq_sync,
- !info->wait_ring_available);
- spin_lock_irq(host->host_lock);
- }
- spin_unlock_irq(host->host_lock);
- err = wait_event_interruptible(shadow->wq_reset, shadow->wait_reset);
- spin_lock_irq(host->host_lock);
- if (!err) {
- err = shadow->rslt_reset;
- scsifront_put_rqid(info, shadow->rqid);
- kfree(shadow);
- } else {
- spin_lock(&info->shadow_lock);
- shadow->rslt_reset = RSLT_RESET_ERR;
- spin_unlock(&info->shadow_lock);
- err = FAILED;
- }
- scsifront_return(info);
- spin_unlock_irq(host->host_lock);
- return err;
- fail:
- spin_unlock_irq(host->host_lock);
- kfree(shadow);
- return FAILED;
- }
- static int scsifront_eh_abort_handler(struct scsi_cmnd *sc)
- {
- pr_debug("%s\n", __func__);
- return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_ABORT);
- }
- static int scsifront_dev_reset_handler(struct scsi_cmnd *sc)
- {
- pr_debug("%s\n", __func__);
- return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_RESET);
- }
- static int scsifront_sdev_configure(struct scsi_device *sdev)
- {
- struct vscsifrnt_info *info = shost_priv(sdev->host);
- int err;
- if (info->host_active == STATE_ERROR)
- return -EIO;
- if (info && current == info->curr) {
- err = xenbus_printf(XBT_NIL, info->dev->nodename,
- info->dev_state_path, "%d", XenbusStateConnected);
- if (err) {
- xenbus_dev_error(info->dev, err,
- "%s: writing dev_state_path", __func__);
- return err;
- }
- }
- return 0;
- }
- static void scsifront_sdev_destroy(struct scsi_device *sdev)
- {
- struct vscsifrnt_info *info = shost_priv(sdev->host);
- int err;
- if (info && current == info->curr) {
- err = xenbus_printf(XBT_NIL, info->dev->nodename,
- info->dev_state_path, "%d", XenbusStateClosed);
- if (err)
- xenbus_dev_error(info->dev, err,
- "%s: writing dev_state_path", __func__);
- }
- }
- static struct scsi_host_template scsifront_sht = {
- .module = THIS_MODULE,
- .name = "Xen SCSI frontend driver",
- .queuecommand = scsifront_queuecommand,
- .eh_abort_handler = scsifront_eh_abort_handler,
- .eh_device_reset_handler = scsifront_dev_reset_handler,
- .slave_configure = scsifront_sdev_configure,
- .slave_destroy = scsifront_sdev_destroy,
- .cmd_per_lun = VSCSIIF_DEFAULT_CMD_PER_LUN,
- .can_queue = VSCSIIF_MAX_REQS,
- .this_id = -1,
- .cmd_size = sizeof(struct vscsifrnt_shadow),
- .sg_tablesize = VSCSIIF_SG_TABLESIZE,
- .proc_name = "scsifront",
- };
- static int scsifront_alloc_ring(struct vscsifrnt_info *info)
- {
- struct xenbus_device *dev = info->dev;
- struct vscsiif_sring *sring;
- int err;
- /***** Frontend to Backend ring start *****/
- err = xenbus_setup_ring(dev, GFP_KERNEL, (void **)&sring, 1,
- &info->ring_ref);
- if (err)
- return err;
- XEN_FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
- err = xenbus_alloc_evtchn(dev, &info->evtchn);
- if (err) {
- xenbus_dev_fatal(dev, err, "xenbus_alloc_evtchn");
- goto free_gnttab;
- }
- err = bind_evtchn_to_irq_lateeoi(info->evtchn);
- if (err <= 0) {
- xenbus_dev_fatal(dev, err, "bind_evtchn_to_irq");
- goto free_gnttab;
- }
- info->irq = err;
- err = request_threaded_irq(info->irq, NULL, scsifront_irq_fn,
- IRQF_ONESHOT, "scsifront", info);
- if (err) {
- xenbus_dev_fatal(dev, err, "request_threaded_irq");
- goto free_irq;
- }
- return 0;
- /* free resource */
- free_irq:
- unbind_from_irqhandler(info->irq, info);
- free_gnttab:
- xenbus_teardown_ring((void **)&sring, 1, &info->ring_ref);
- return err;
- }
- static void scsifront_free_ring(struct vscsifrnt_info *info)
- {
- unbind_from_irqhandler(info->irq, info);
- xenbus_teardown_ring((void **)&info->ring.sring, 1, &info->ring_ref);
- }
- static int scsifront_init_ring(struct vscsifrnt_info *info)
- {
- struct xenbus_device *dev = info->dev;
- struct xenbus_transaction xbt;
- int err;
- pr_debug("%s\n", __func__);
- err = scsifront_alloc_ring(info);
- if (err)
- return err;
- pr_debug("%s: %u %u\n", __func__, info->ring_ref, info->evtchn);
- again:
- err = xenbus_transaction_start(&xbt);
- if (err)
- xenbus_dev_fatal(dev, err, "starting transaction");
- err = xenbus_printf(xbt, dev->nodename, "ring-ref", "%u",
- info->ring_ref);
- if (err) {
- xenbus_dev_fatal(dev, err, "%s", "writing ring-ref");
- goto fail;
- }
- err = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
- info->evtchn);
- if (err) {
- xenbus_dev_fatal(dev, err, "%s", "writing event-channel");
- goto fail;
- }
- err = xenbus_transaction_end(xbt, 0);
- if (err) {
- if (err == -EAGAIN)
- goto again;
- xenbus_dev_fatal(dev, err, "completing transaction");
- goto free_sring;
- }
- return 0;
- fail:
- xenbus_transaction_end(xbt, 1);
- free_sring:
- scsifront_free_ring(info);
- return err;
- }
- static int scsifront_probe(struct xenbus_device *dev,
- const struct xenbus_device_id *id)
- {
- struct vscsifrnt_info *info;
- struct Scsi_Host *host;
- int err = -ENOMEM;
- char name[TASK_COMM_LEN];
- host = scsi_host_alloc(&scsifront_sht, sizeof(*info));
- if (!host) {
- xenbus_dev_fatal(dev, err, "fail to allocate scsi host");
- return err;
- }
- info = (struct vscsifrnt_info *)host->hostdata;
- dev_set_drvdata(&dev->dev, info);
- info->dev = dev;
- bitmap_fill(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
- err = scsifront_init_ring(info);
- if (err) {
- scsi_host_put(host);
- return err;
- }
- init_waitqueue_head(&info->wq_sync);
- init_waitqueue_head(&info->wq_pause);
- spin_lock_init(&info->shadow_lock);
- snprintf(name, TASK_COMM_LEN, "vscsiif.%d", host->host_no);
- host->max_id = VSCSIIF_MAX_TARGET;
- host->max_channel = 0;
- host->max_lun = VSCSIIF_MAX_LUN;
- host->max_sectors = (host->sg_tablesize - 1) * PAGE_SIZE / 512;
- host->max_cmd_len = VSCSIIF_MAX_COMMAND_SIZE;
- err = scsi_add_host(host, &dev->dev);
- if (err) {
- dev_err(&dev->dev, "fail to add scsi host %d\n", err);
- goto free_sring;
- }
- info->host = host;
- info->host_active = STATE_ACTIVE;
- xenbus_switch_state(dev, XenbusStateInitialised);
- return 0;
- free_sring:
- scsifront_free_ring(info);
- scsi_host_put(host);
- return err;
- }
- static int scsifront_resume(struct xenbus_device *dev)
- {
- struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
- struct Scsi_Host *host = info->host;
- int err;
- spin_lock_irq(host->host_lock);
- /* Finish all still pending commands. */
- scsifront_finish_all(info);
- spin_unlock_irq(host->host_lock);
- /* Reconnect to dom0. */
- scsifront_free_ring(info);
- err = scsifront_init_ring(info);
- if (err) {
- dev_err(&dev->dev, "fail to resume %d\n", err);
- scsi_host_put(host);
- return err;
- }
- xenbus_switch_state(dev, XenbusStateInitialised);
- return 0;
- }
- static int scsifront_suspend(struct xenbus_device *dev)
- {
- struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
- struct Scsi_Host *host = info->host;
- int err = 0;
- /* No new commands for the backend. */
- spin_lock_irq(host->host_lock);
- info->pause = 1;
- while (info->callers && !err) {
- info->waiting_pause = 1;
- info->wait_ring_available = 0;
- spin_unlock_irq(host->host_lock);
- wake_up(&info->wq_sync);
- err = wait_event_interruptible(info->wq_pause,
- !info->waiting_pause);
- spin_lock_irq(host->host_lock);
- }
- spin_unlock_irq(host->host_lock);
- return err;
- }
- static int scsifront_remove(struct xenbus_device *dev)
- {
- struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
- pr_debug("%s: %s removed\n", __func__, dev->nodename);
- mutex_lock(&scsifront_mutex);
- if (info->host_active != STATE_INACTIVE) {
- /* Scsi_host not yet removed */
- scsi_remove_host(info->host);
- info->host_active = STATE_INACTIVE;
- }
- mutex_unlock(&scsifront_mutex);
- scsifront_free_ring(info);
- scsi_host_put(info->host);
- return 0;
- }
- static void scsifront_disconnect(struct vscsifrnt_info *info)
- {
- struct xenbus_device *dev = info->dev;
- struct Scsi_Host *host = info->host;
- pr_debug("%s: %s disconnect\n", __func__, dev->nodename);
- /*
- * When this function is executed, all devices of
- * Frontend have been deleted.
- * Therefore, it need not block I/O before remove_host.
- */
- mutex_lock(&scsifront_mutex);
- if (info->host_active != STATE_INACTIVE) {
- scsi_remove_host(host);
- info->host_active = STATE_INACTIVE;
- }
- mutex_unlock(&scsifront_mutex);
- xenbus_frontend_closed(dev);
- }
- static void scsifront_do_lun_hotplug(struct vscsifrnt_info *info, int op)
- {
- struct xenbus_device *dev = info->dev;
- int i, err = 0;
- char str[64];
- char **dir;
- unsigned int dir_n = 0;
- unsigned int device_state;
- unsigned int hst, chn, tgt, lun;
- struct scsi_device *sdev;
- if (info->host_active == STATE_ERROR)
- return;
- dir = xenbus_directory(XBT_NIL, dev->otherend, "vscsi-devs", &dir_n);
- if (IS_ERR(dir))
- return;
- /* mark current task as the one allowed to modify device states */
- BUG_ON(info->curr);
- info->curr = current;
- for (i = 0; i < dir_n; i++) {
- /* read status */
- snprintf(str, sizeof(str), "vscsi-devs/%s/state", dir[i]);
- err = xenbus_scanf(XBT_NIL, dev->otherend, str, "%u",
- &device_state);
- if (XENBUS_EXIST_ERR(err))
- continue;
- /* virtual SCSI device */
- snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", dir[i]);
- err = xenbus_scanf(XBT_NIL, dev->otherend, str,
- "%u:%u:%u:%u", &hst, &chn, &tgt, &lun);
- if (XENBUS_EXIST_ERR(err))
- continue;
- /*
- * Front device state path, used in slave_configure called
- * on successfull scsi_add_device, and in slave_destroy called
- * on remove of a device.
- */
- snprintf(info->dev_state_path, sizeof(info->dev_state_path),
- "vscsi-devs/%s/state", dir[i]);
- switch (op) {
- case VSCSIFRONT_OP_ADD_LUN:
- if (device_state != XenbusStateInitialised)
- break;
- if (scsi_add_device(info->host, chn, tgt, lun)) {
- dev_err(&dev->dev, "scsi_add_device\n");
- err = xenbus_printf(XBT_NIL, dev->nodename,
- info->dev_state_path,
- "%d", XenbusStateClosed);
- if (err)
- xenbus_dev_error(dev, err,
- "%s: writing dev_state_path", __func__);
- }
- break;
- case VSCSIFRONT_OP_DEL_LUN:
- if (device_state != XenbusStateClosing)
- break;
- sdev = scsi_device_lookup(info->host, chn, tgt, lun);
- if (sdev) {
- scsi_remove_device(sdev);
- scsi_device_put(sdev);
- }
- break;
- case VSCSIFRONT_OP_READD_LUN:
- if (device_state == XenbusStateConnected) {
- err = xenbus_printf(XBT_NIL, dev->nodename,
- info->dev_state_path,
- "%d", XenbusStateConnected);
- if (err)
- xenbus_dev_error(dev, err,
- "%s: writing dev_state_path", __func__);
- }
- break;
- default:
- break;
- }
- }
- info->curr = NULL;
- kfree(dir);
- }
- static void scsifront_read_backend_params(struct xenbus_device *dev,
- struct vscsifrnt_info *info)
- {
- unsigned int sg_grant, nr_segs;
- struct Scsi_Host *host = info->host;
- sg_grant = xenbus_read_unsigned(dev->otherend, "feature-sg-grant", 0);
- nr_segs = min_t(unsigned int, sg_grant, SG_ALL);
- nr_segs = max_t(unsigned int, nr_segs, VSCSIIF_SG_TABLESIZE);
- nr_segs = min_t(unsigned int, nr_segs,
- VSCSIIF_SG_TABLESIZE * PAGE_SIZE /
- sizeof(struct scsiif_request_segment));
- if (!info->pause && sg_grant)
- dev_info(&dev->dev, "using up to %d SG entries\n", nr_segs);
- else if (info->pause && nr_segs < host->sg_tablesize)
- dev_warn(&dev->dev,
- "SG entries decreased from %d to %u - device may not work properly anymore\n",
- host->sg_tablesize, nr_segs);
- host->sg_tablesize = nr_segs;
- host->max_sectors = (nr_segs - 1) * PAGE_SIZE / 512;
- }
- static void scsifront_backend_changed(struct xenbus_device *dev,
- enum xenbus_state backend_state)
- {
- struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
- pr_debug("%s: %p %u %u\n", __func__, dev, dev->state, backend_state);
- switch (backend_state) {
- case XenbusStateUnknown:
- case XenbusStateInitialising:
- case XenbusStateInitWait:
- case XenbusStateInitialised:
- break;
- case XenbusStateConnected:
- scsifront_read_backend_params(dev, info);
- if (info->pause) {
- scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_READD_LUN);
- xenbus_switch_state(dev, XenbusStateConnected);
- info->pause = 0;
- return;
- }
- if (xenbus_read_driver_state(dev->nodename) ==
- XenbusStateInitialised)
- scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN);
- if (dev->state != XenbusStateConnected)
- xenbus_switch_state(dev, XenbusStateConnected);
- break;
- case XenbusStateClosed:
- if (dev->state == XenbusStateClosed)
- break;
- fallthrough; /* Missed the backend's Closing state */
- case XenbusStateClosing:
- scsifront_disconnect(info);
- break;
- case XenbusStateReconfiguring:
- scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_DEL_LUN);
- xenbus_switch_state(dev, XenbusStateReconfiguring);
- break;
- case XenbusStateReconfigured:
- scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN);
- xenbus_switch_state(dev, XenbusStateConnected);
- break;
- }
- }
- static const struct xenbus_device_id scsifront_ids[] = {
- { "vscsi" },
- { "" }
- };
- static struct xenbus_driver scsifront_driver = {
- .ids = scsifront_ids,
- .probe = scsifront_probe,
- .remove = scsifront_remove,
- .resume = scsifront_resume,
- .suspend = scsifront_suspend,
- .otherend_changed = scsifront_backend_changed,
- };
- static int __init scsifront_init(void)
- {
- if (!xen_domain())
- return -ENODEV;
- return xenbus_register_frontend(&scsifront_driver);
- }
- module_init(scsifront_init);
- static void __exit scsifront_exit(void)
- {
- xenbus_unregister_driver(&scsifront_driver);
- }
- module_exit(scsifront_exit);
- MODULE_DESCRIPTION("Xen SCSI frontend driver");
- MODULE_LICENSE("GPL");
- MODULE_ALIAS("xen:vscsi");
- MODULE_AUTHOR("Juergen Gross <[email protected]>");
|