diff options
Diffstat (limited to 'drivers/scsi/scsi_tgt_lib.c')
| -rw-r--r-- | drivers/scsi/scsi_tgt_lib.c | 742 |
1 files changed, 742 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c new file mode 100644 index 000000000000..39da5cd6fb6f --- /dev/null +++ b/drivers/scsi/scsi_tgt_lib.c @@ -0,0 +1,742 @@ +/* + * SCSI target lib functions + * + * Copyright (C) 2005 Mike Christie <michaelc@cs.wisc.edu> + * Copyright (C) 2005 FUJITA Tomonori <tomof@acm.org> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA + * 02110-1301 USA + */ +#include <linux/blkdev.h> +#include <linux/hash.h> +#include <linux/module.h> +#include <linux/pagemap.h> +#include <scsi/scsi.h> +#include <scsi/scsi_cmnd.h> +#include <scsi/scsi_device.h> +#include <scsi/scsi_host.h> +#include <scsi/scsi_tgt.h> +#include <../drivers/md/dm-bio-list.h> + +#include "scsi_tgt_priv.h" + +static struct workqueue_struct *scsi_tgtd; +static kmem_cache_t *scsi_tgt_cmd_cache; + +/* + * TODO: this struct will be killed when the block layer supports large bios + * and James's work struct code is in + */ +struct scsi_tgt_cmd { + /* TODO replace work with James b's code */ + struct work_struct work; + /* TODO replace the lists with a large bio */ + struct bio_list xfer_done_list; + struct bio_list xfer_list; + + struct list_head hash_list; + struct request *rq; + u64 tag; + + void *buffer; + unsigned bufflen; +}; + +#define TGT_HASH_ORDER 4 +#define cmd_hashfn(tag) hash_long((unsigned long) (tag), TGT_HASH_ORDER) + +struct scsi_tgt_queuedata { + struct Scsi_Host *shost; + struct list_head cmd_hash[1 << TGT_HASH_ORDER]; + spinlock_t cmd_hash_lock; +}; + +/* + * Function: scsi_host_get_command() + * + * Purpose: Allocate and setup a scsi command block and blk request + * + * Arguments: shost - scsi host + * data_dir - dma data dir + * gfp_mask- allocator flags + * + * Returns: The allocated scsi command structure. + * + * This should be called by target LLDs to get a command. + */ +struct scsi_cmnd *scsi_host_get_command(struct Scsi_Host *shost, + enum dma_data_direction data_dir, + gfp_t gfp_mask) +{ + int write = (data_dir == DMA_TO_DEVICE); + struct request *rq; + struct scsi_cmnd *cmd; + struct scsi_tgt_cmd *tcmd; + + /* Bail if we can't get a reference to the device */ + if (!get_device(&shost->shost_gendev)) + return NULL; + + tcmd = kmem_cache_alloc(scsi_tgt_cmd_cache, GFP_ATOMIC); + if (!tcmd) + goto put_dev; + + rq = blk_get_request(shost->uspace_req_q, write, gfp_mask); + if (!rq) + goto free_tcmd; + + cmd = __scsi_get_command(shost, gfp_mask); + if (!cmd) + goto release_rq; + + memset(cmd, 0, sizeof(*cmd)); + cmd->sc_data_direction = data_dir; + cmd->jiffies_at_alloc = jiffies; + cmd->request = rq; + + rq->special = cmd; + rq->cmd_type = REQ_TYPE_SPECIAL; + rq->cmd_flags |= REQ_TYPE_BLOCK_PC; + rq->end_io_data = tcmd; + + bio_list_init(&tcmd->xfer_list); + bio_list_init(&tcmd->xfer_done_list); + tcmd->rq = rq; + + return cmd; + +release_rq: + blk_put_request(rq); +free_tcmd: + kmem_cache_free(scsi_tgt_cmd_cache, tcmd); +put_dev: + put_device(&shost->shost_gendev); + return NULL; + +} +EXPORT_SYMBOL_GPL(scsi_host_get_command); + +/* + * Function: scsi_host_put_command() + * + * Purpose: Free a scsi command block + * + * Arguments: shost - scsi host + * cmd - command block to free + * + * Returns: Nothing. + * + * Notes: The command must not belong to any lists. + */ +void scsi_host_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd) +{ + struct request_queue *q = shost->uspace_req_q; + struct request *rq = cmd->request; + struct scsi_tgt_cmd *tcmd = rq->end_io_data; + unsigned long flags; + + kmem_cache_free(scsi_tgt_cmd_cache, tcmd); + + spin_lock_irqsave(q->queue_lock, flags); + __blk_put_request(q, rq); + spin_unlock_irqrestore(q->queue_lock, flags); + + __scsi_put_command(shost, cmd, &shost->shost_gendev); +} +EXPORT_SYMBOL_GPL(scsi_host_put_command); + +static void scsi_unmap_user_pages(struct scsi_tgt_cmd *tcmd) +{ + struct bio *bio; + + /* must call bio_endio in case bio was bounced */ + while ((bio = bio_list_pop(&tcmd->xfer_done_list))) { + bio_endio(bio, bio->bi_size, 0); + bio_unmap_user(bio); + } + + while ((bio = bio_list_pop(&tcmd->xfer_list))) { + bio_endio(bio, bio->bi_size, 0); + bio_unmap_user(bio); + } +} + +static void cmd_hashlist_del(struct scsi_cmnd *cmd) +{ + struct request_queue *q = cmd->request->q; + struct scsi_tgt_queuedata *qdata = q->queuedata; + unsigned long flags; + struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data; + + spin_lock_irqsave(&qdata->cmd_hash_lock, flags); + list_del(&tcmd->hash_list); + spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags); +} + +static void scsi_tgt_cmd_destroy(void *data) +{ + struct scsi_cmnd *cmd = data; + struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data; + + dprintk("cmd %p %d %lu\n", cmd, cmd->sc_data_direction, + rq_data_dir(cmd->request)); + /* + * We fix rq->cmd_flags here since when we told bio_map_user + * to write vm for WRITE commands, blk_rq_bio_prep set + * rq_data_dir the flags to READ. + */ + if (cmd->sc_data_direction == DMA_TO_DEVICE) + cmd->request->cmd_flags |= REQ_RW; + else + cmd->request->cmd_flags &= ~REQ_RW; + + scsi_unmap_user_pages(tcmd); + scsi_host_put_command(scsi_tgt_cmd_to_host(cmd), cmd); +} + +static void init_scsi_tgt_cmd(struct request *rq, struct scsi_tgt_cmd *tcmd, + u64 tag) +{ + struct scsi_tgt_queuedata *qdata = rq->q->queuedata; + unsigned long flags; + struct list_head *head; + + tcmd->tag = tag; + spin_lock_irqsave(&qdata->cmd_hash_lock, flags); + head = &qdata->cmd_hash[cmd_hashfn(tag)]; + list_add(&tcmd->hash_list, head); + spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags); +} + +/* + * scsi_tgt_alloc_queue - setup queue used for message passing + * shost: scsi host + * + * This should be called by the LLD after host allocation. + * And will be released when the host is released. + */ +int scsi_tgt_alloc_queue(struct Scsi_Host *shost) +{ + struct scsi_tgt_queuedata *queuedata; + struct request_queue *q; + int err, i; + + /* + * Do we need to send a netlink event or should uspace + * just respond to the hotplug event? + */ + q = __scsi_alloc_queue(shost, NULL); + if (!q) + return -ENOMEM; + + queuedata = kzalloc(sizeof(*queuedata), GFP_KERNEL); + if (!queuedata) { + err = -ENOMEM; + goto cleanup_queue; + } + queuedata->shost = shost; + q->queuedata = queuedata; + + /* + * this is a silly hack. We should probably just queue as many + * command as is recvd to userspace. uspace can then make + * sure we do not overload the HBA + */ + q->nr_requests = shost->hostt->can_queue; + /* + * We currently only support software LLDs so this does + * not matter for now. Do we need this for the cards we support? + * If so we should make it a host template value. + */ + blk_queue_dma_alignment(q, 0); + shost->uspace_req_q = q; + + for (i = 0; i < ARRAY_SIZE(queuedata->cmd_hash); i++) + INIT_LIST_HEAD(&queuedata->cmd_hash[i]); + spin_lock_init(&queuedata->cmd_hash_lock); + + return 0; + +cleanup_queue: + blk_cleanup_queue(q); + return err; +} +EXPORT_SYMBOL_GPL(scsi_tgt_alloc_queue); + +void scsi_tgt_free_queue(struct Scsi_Host *shost) +{ + int i; + unsigned long flags; + struct request_queue *q = shost->uspace_req_q; + struct scsi_cmnd *cmd; + struct scsi_tgt_queuedata *qdata = q->queuedata; + struct scsi_tgt_cmd *tcmd, *n; + LIST_HEAD(cmds); + + spin_lock_irqsave(&qdata->cmd_hash_lock, flags); + + for (i = 0; i < ARRAY_SIZE(qdata->cmd_hash); i++) { + list_for_each_entry_safe(tcmd, n, &qdata->cmd_hash[i], + hash_list) { + list_del(&tcmd->hash_list); + list_add(&tcmd->hash_list, &cmds); + } + } + + spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags); + + while (!list_empty(&cmds)) { + tcmd = list_entry(cmds.next, struct scsi_tgt_cmd, hash_list); + list_del(&tcmd->hash_list); + cmd = tcmd->rq->special; + + shost->hostt->eh_abort_handler(cmd); + scsi_tgt_cmd_destroy(cmd); + } +} +EXPORT_SYMBOL_GPL(scsi_tgt_free_queue); + +struct Scsi_Host *scsi_tgt_cmd_to_host(struct scsi_cmnd *cmd) +{ + struct scsi_tgt_queuedata *queue = cmd->request->q->queuedata; + return queue->shost; +} +EXPORT_SYMBOL_GPL(scsi_tgt_cmd_to_host); + +/* + * scsi_tgt_queue_command - queue command for userspace processing + * @cmd: scsi command + * @scsilun: scsi lun + * @tag: unique value to identify this command for tmf + */ +int scsi_tgt_queue_command(struct scsi_cmnd *cmd, struct scsi_lun *scsilun, + u64 tag) +{ + struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data; + int err; + + init_scsi_tgt_cmd(cmd->request, tcmd, tag); + err = scsi_tgt_uspace_send_cmd(cmd, scsilun, tag); + if (err) + cmd_hashlist_del(cmd); + + return err; +} +EXPORT_SYMBOL_GPL(scsi_tgt_queue_command); + +/* + * This is run from a interrpt handler normally and the unmap + * needs process context so we must queue + */ +static void scsi_tgt_cmd_done(struct scsi_cmnd *cmd) +{ + struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data; + + dprintk("cmd %p %lu\n", cmd, rq_data_dir(cmd->request)); + + scsi_tgt_uspace_send_status(cmd, tcmd->tag); + INIT_WORK(&tcmd->work, scsi_tgt_cmd_destroy, cmd); + queue_work(scsi_tgtd, &tcmd->work); +} + +static int __scsi_tgt_transfer_response(struct scsi_cmnd *cmd) +{ + struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd); + int err; + + dprintk("cmd %p %lu\n", cmd, rq_data_dir(cmd->request)); + + err = shost->hostt->transfer_response(cmd, scsi_tgt_cmd_done); + switch (err) { + case SCSI_MLQUEUE_HOST_BUSY: + case SCSI_MLQUEUE_DEVICE_BUSY: + return -EAGAIN; + } + + return 0; +} + +static void scsi_tgt_transfer_response(struct scsi_cmnd *cmd) +{ + struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data; + int err; + + err = __scsi_tgt_transfer_response(cmd); + if (!err) + return; + + cmd->result = DID_BUS_BUSY << 16; + err = scsi_tgt_uspace_send_status(cmd, tcmd->tag); + if (err <= 0) + /* the eh will have to pick this up */ + printk(KERN_ERR "Could not send cmd %p status\n", cmd); +} + +static int scsi_tgt_init_cmd(struct scsi_cmnd *cmd, gfp_t gfp_mask) +{ + struct request *rq = cmd->request; + struct scsi_tgt_cmd *tcmd = rq->end_io_data; + int count; + + cmd->use_sg = rq->nr_phys_segments; + cmd->request_buffer = scsi_alloc_sgtable(cmd, gfp_mask); + if (!cmd->request_buffer) + return -ENOMEM; + + cmd->request_bufflen = rq->data_len; + + dprintk("cmd %p addr %p cnt %d %lu\n", cmd, tcmd->buffer, cmd->use_sg, + rq_data_dir(rq)); + count = blk_rq_map_sg(rq->q, rq, cmd->request_buffer); + if (likely(count <= cmd->use_sg)) { + cmd->use_sg = count; + return 0; + } + + eprintk("cmd %p addr %p cnt %d\n", cmd, tcmd->buffer, cmd->use_sg); + scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len); + return -EINVAL; +} + +/* TODO: test this crap and replace bio_map_user with new interface maybe */ +static int scsi_map_user_pages(struct scsi_tgt_cmd *tcmd, struct scsi_cmnd *cmd, + int rw) +{ + struct request_queue *q = cmd->request->q; + struct request *rq = cmd->request; + void *uaddr = tcmd->buffer; + unsigned int len = tcmd->bufflen; + struct bio *bio; + int err; + + while (len > 0) { + dprintk("%lx %u\n", (unsigned long) uaddr, len); + bio = bio_map_user(q, NULL, (unsigned long) uaddr, len, rw); + if (IS_ERR(bio)) { + err = PTR_ERR(bio); + dprintk("fail to map %lx %u %d %x\n", + (unsigned long) uaddr, len, err, cmd->cmnd[0]); + goto unmap_bios; + } + + uaddr += bio->bi_size; + len -= bio->bi_size; + + /* + * The first bio is added and merged. We could probably + * try to add others using scsi_merge_bio() but for now + * we keep it simple. The first bio should be pretty large + * (either hitting the 1 MB bio pages limit or a queue limit) + * already but for really large IO we may want to try and + * merge these. + */ + if (!rq->bio) { + blk_rq_bio_prep(q, rq, bio); + rq->data_len = bio->bi_size; + } else + /* put list of bios to transfer in next go around */ + bio_list_add(&tcmd->xfer_list, bio); + } + + cmd->offset = 0; + err = scsi_tgt_init_cmd(cmd, GFP_KERNEL); + if (err) + goto unmap_bios; + + return 0; + +unmap_bios: + if (rq->bio) { + bio_unmap_user(rq->bio); + while ((bio = bio_list_pop(&tcmd->xfer_list))) + bio_unmap_user(bio); + } + + return err; +} + +static int scsi_tgt_transfer_data(struct scsi_cmnd *); + +static void scsi_tgt_data_transfer_done(struct scsi_cmnd *cmd) +{ + struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data; + struct bio *bio; + int err; + + /* should we free resources here on error ? */ + if (cmd->result) { +send_uspace_err: + err = scsi_tgt_uspace_send_status(cmd, tcmd->tag); + if (err <= 0) + /* the tgt uspace eh will have to pick this up */ + printk(KERN_ERR "Could not send cmd %p status\n", cmd); + return; + } + + dprintk("cmd %p request_bufflen %u bufflen %u\n", + cmd, cmd->request_bufflen, tcmd->bufflen); + + scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len); + bio_list_add(&tcmd->xfer_done_list, cmd->request->bio); + + tcmd->buffer += cmd->request_bufflen; + cmd->offset += cmd->request_bufflen; + + if (!tcmd->xfer_list.head) { + scsi_tgt_transfer_response(cmd); + return; + } + + dprintk("cmd2 %p request_bufflen %u bufflen %u\n", + cmd, cmd->request_bufflen, tcmd->bufflen); + + bio = bio_list_pop(&tcmd->xfer_list); + BUG_ON(!bio); + + blk_rq_bio_prep(cmd->request->q, cmd->request, bio); + cmd->request->data_len = bio->bi_size; + err = scsi_tgt_init_cmd(cmd, GFP_ATOMIC); + if (err) { + cmd->result = DID_ERROR << 16; + goto send_uspace_err; + } + + if (scsi_tgt_transfer_data(cmd)) { + cmd->result = DID_NO_CONNECT << 16; + goto send_uspace_err; + } +} + +static int scsi_tgt_transfer_data(struct scsi_cmnd *cmd) +{ + int err; + struct Scsi_Host *host = scsi_tgt_cmd_to_host(cmd); + + err = host->hostt->transfer_data(cmd, scsi_tgt_data_transfer_done); + switch (err) { + case SCSI_MLQUEUE_HOST_BUSY: + case SCSI_MLQUEUE_DEVICE_BUSY: + return -EAGAIN; + default: + return 0; + } +} + +static int scsi_tgt_copy_sense(struct scsi_cmnd *cmd, unsigned long uaddr, + unsigned len) +{ + char __user *p = (char __user *) uaddr; + + if (copy_from_user(cmd->sense_buffer, p, + min_t(unsigned, SCSI_SENSE_BUFFERSIZE, len))) { + printk(KERN_ERR "Could not copy the sense buffer\n"); + return -EIO; + } + return 0; +} + +static int scsi_tgt_abort_cmd(struct Scsi_Host *shost, struct scsi_cmnd *cmd) +{ + int err; + + err = shost->hostt->eh_abort_handler(cmd); + if (err) + eprintk("fail to abort %p\n", cmd); + + scsi_tgt_cmd_destroy(cmd); + return err; +} + +static struct request *tgt_cmd_hash_lookup(struct request_queue *q, u64 tag) +{ + struct scsi_tgt_queuedata *qdata = q->queuedata; + struct request *rq = NULL; + struct list_head *head; + struct scsi_tgt_cmd *tcmd; + unsigned long flags; + + head = &qdata->cmd_hash[cmd_hashfn(tag)]; + spin_lock_irqsave(&qdata->cmd_hash_lock, flags); + list_for_each_entry(tcmd, head, hash_list) { + if (tcmd->tag == tag) { + rq = tcmd->rq; + list_del(&tcmd->hash_list); + break; + } + } + spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags); + + return rq; +} + +int scsi_tgt_kspace_exec(int host_no, u64 tag, int result, u32 len, + unsigned long uaddr, u8 rw) +{ + struct Scsi_Host *shost; + struct scsi_cmnd *cmd; + struct request *rq; + struct scsi_tgt_cmd *tcmd; + int err = 0; + + dprintk("%d %llu %d %u %lx %u\n", host_no, (unsigned long long) tag, + result, len, uaddr, rw); + + /* TODO: replace with a O(1) alg */ + shost = scsi_host_lookup(host_no); + if (IS_ERR(shost)) { + printk(KERN_ERR "Could not find host no %d\n", host_no); + return -EINVAL; + } + + if (!shost->uspace_req_q) { + printk(KERN_ERR "Not target scsi host %d\n", host_no); + goto done; + } + + rq = tgt_cmd_hash_lookup(shost->uspace_req_q, tag); + if (!rq) { + printk(KERN_ERR "Could not find tag %llu\n", + (unsigned long long) tag); + err = -EINVAL; + goto done; + } + cmd = rq->special; + + dprintk("cmd %p result %d len %d bufflen %u %lu %x\n", cmd, + result, len, cmd->request_bufflen, rq_data_dir(rq), cmd->cmnd[0]); + + if (result == TASK_ABORTED) { + scsi_tgt_abort_cmd(shost, cmd); + goto done; + } + /* + * store the userspace values here, the working values are + * in the request_* values + */ + tcmd = cmd->request->end_io_data; + tcmd->buffer = (void *)uaddr; + tcmd->bufflen = len; + cmd->result = result; + + if (!tcmd->bufflen || cmd->request_buffer) { + err = __scsi_tgt_transfer_response(cmd); + goto done; + } + + /* + * TODO: Do we need to handle case where request does not + * align with LLD. + */ + err = scsi_map_user_pages(rq->end_io_data, cmd, rw); + if (err) { + eprintk("%p %d\n", cmd, err); + err = -EAGAIN; + goto done; + } + + /* userspace failure */ + if (cmd->result) { + if (status_byte(cmd->result) == CHECK_CONDITION) + scsi_tgt_copy_sense(cmd, uaddr, len); + err = __scsi_tgt_transfer_response(cmd); + goto done; + } + /* ask the target LLD to transfer the data to the buffer */ + err = scsi_tgt_transfer_data(cmd); + +done: + scsi_host_put(shost); + return err; +} + +int scsi_tgt_tsk_mgmt_request(struct Scsi_Host *shost, int function, u64 tag, + struct scsi_lun *scsilun, void *data) +{ + int err; + + /* TODO: need to retry if this fails. */ + err = scsi_tgt_uspace_send_tsk_mgmt(shost->host_no, function, + tag, scsilun, data); + if (err < 0) + eprintk("The task management request lost!\n"); + return err; +} +EXPORT_SYMBOL_GPL(scsi_tgt_tsk_mgmt_request); + +int scsi_tgt_kspace_tsk_mgmt(int host_no, u64 mid, int result) +{ + struct Scsi_Host *shost; + int err = -EINVAL; + + dprintk("%d %d %llx\n", host_no, result, (unsigned long long) mid); + + shost = scsi_host_lookup(host_no); + if (IS_ERR(shost)) { + printk(KERN_ERR "Could not find host no %d\n", host_no); + return err; + } + + if (!shost->uspace_req_q) { + printk(KERN_ERR "Not target scsi host %d\n", host_no); + goto done; + } + + err = shost->hostt->tsk_mgmt_response(mid, result); +done: + scsi_host_put(shost); + return err; +} + +static int __init scsi_tgt_init(void) +{ + int err; + + scsi_tgt_cmd_cache = kmem_cache_create("scsi_tgt_cmd", + sizeof(struct scsi_tgt_cmd), + 0, 0, NULL, NULL); + if (!scsi_tgt_cmd_cache) + return -ENOMEM; + + scsi_tgtd = create_workqueue("scsi_tgtd"); + if (!scsi_tgtd) { + err = -ENOMEM; + goto free_kmemcache; + } + + err = scsi_tgt_if_init(); + if (err) + goto destroy_wq; + + return 0; + +destroy_wq: + destroy_workqueue(scsi_tgtd); +free_kmemcache: + kmem_cache_destroy(scsi_tgt_cmd_cache); + return err; +} + +static void __exit scsi_tgt_exit(void) +{ + destroy_workqueue(scsi_tgtd); + scsi_tgt_if_exit(); + kmem_cache_destroy(scsi_tgt_cmd_cache); +} + +module_init(scsi_tgt_init); +module_exit(scsi_tgt_exit); + +MODULE_DESCRIPTION("SCSI target core"); +MODULE_LICENSE("GPL"); |