This is main functionality of ibnbd-client module, which provides interface to map remote device as local block device /dev/ibnbd<N> and feeds IBTRS with IO requests. Signed-off-by: Roman Pen <roman.penyaev@xxxxxxxxxxxxxxxx> Signed-off-by: Danil Kipnis <danil.kipnis@xxxxxxxxxxxxxxxx> Cc: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxxx> --- drivers/block/ibnbd/ibnbd-clt.c | 1819 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 1819 insertions(+) create mode 100644 drivers/block/ibnbd/ibnbd-clt.c diff --git a/drivers/block/ibnbd/ibnbd-clt.c b/drivers/block/ibnbd/ibnbd-clt.c new file mode 100644 index 000000000000..06524e33e19f --- /dev/null +++ b/drivers/block/ibnbd/ibnbd-clt.c @@ -0,0 +1,1819 @@ +/* + * InfiniBand Network Block Driver + * + * Copyright (c) 2014 - 2017 ProfitBricks GmbH. All rights reserved. + * Authors: Fabian Holler <mail@xxxxxxxxxx> + * Jack Wang <jinpu.wang@xxxxxxxxxxxxxxxx> + * Kleber Souza <kleber.souza@xxxxxxxxxxxxxxxx> + * Danil Kipnis <danil.kipnis@xxxxxxxxxxxxxxxx> + * Roman Penyaev <roman.penyaev@xxxxxxxxxxxxxxxx> + * Milind Dumbare <Milind.dumbare@xxxxxxxxx> + * + * Copyright (c) 2017 - 2018 ProfitBricks GmbH. All rights reserved. + * Authors: Danil Kipnis <danil.kipnis@xxxxxxxxxxxxxxxx> + * Roman Penyaev <roman.penyaev@xxxxxxxxxxxxxxxx> + * Swapnil Ingle <swapnil.ingle@xxxxxxxxxxxxxxxx> + * + * 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, see <http://www.gnu.org/licenses/>. + */ + +#undef pr_fmt +#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt + +#include <linux/module.h> +#include <linux/blkdev.h> +#include <linux/hdreg.h> +#include <linux/scatterlist.h> +#include <linux/idr.h> + +#include "ibnbd-clt.h" + +MODULE_AUTHOR("ibnbd@xxxxxxxxxxxxxxxx"); +MODULE_DESCRIPTION("InfiniBand Network Block Device Client"); +MODULE_VERSION(IBNBD_VER_STRING); +MODULE_LICENSE("GPL"); + +/* + * This is for closing devices when unloading the module: + * we might be closing a lot (>256) of devices in parallel + * and it is better not to use the system_wq. + */ +static struct workqueue_struct *unload_wq; +static int ibnbd_client_major; +static DEFINE_IDA(index_ida); +static DEFINE_MUTEX(ida_lock); +static DEFINE_MUTEX(sess_lock); +static LIST_HEAD(sess_list); + +static bool softirq_enable; +module_param(softirq_enable, bool, 0444); +MODULE_PARM_DESC(softirq_enable, "finish request in softirq_fn." + " (default: 0)"); +/* + * Maximum number of partitions an instance can have. + * 6 bits = 64 minors = 63 partitions (one minor is used for the device itself) + */ +#define IBNBD_PART_BITS 6 +#define KERNEL_SECTOR_SIZE 512 + +static inline bool ibnbd_clt_get_sess(struct ibnbd_clt_session *sess) +{ + return refcount_inc_not_zero(&sess->refcount); +} + +static void free_sess(struct ibnbd_clt_session *sess); + +static void ibnbd_clt_put_sess(struct ibnbd_clt_session *sess) +{ + might_sleep(); + + if (refcount_dec_and_test(&sess->refcount)) + free_sess(sess); +} + +static inline bool ibnbd_clt_dev_is_mapped(struct ibnbd_clt_dev *dev) +{ + return dev->dev_state == DEV_STATE_MAPPED; +} + +static void ibnbd_clt_put_dev(struct ibnbd_clt_dev *dev) +{ + might_sleep(); + + if (refcount_dec_and_test(&dev->refcount)) { + mutex_lock(&ida_lock); + ida_simple_remove(&index_ida, dev->clt_device_id); + mutex_unlock(&ida_lock); + kfree(dev->hw_queues); + ibnbd_clt_put_sess(dev->sess); + kfree(dev); + } +} + +static inline bool ibnbd_clt_get_dev(struct ibnbd_clt_dev *dev) +{ + return refcount_inc_not_zero(&dev->refcount); +} + +static int ibnbd_clt_set_dev_attr(struct ibnbd_clt_dev *dev, + const struct ibnbd_msg_open_rsp *rsp) +{ + struct ibnbd_clt_session *sess = dev->sess; + + if (unlikely(!rsp->logical_block_size)) + return -EINVAL; + + dev->device_id = le32_to_cpu(rsp->device_id); + dev->nsectors = le64_to_cpu(rsp->nsectors); + dev->logical_block_size = le16_to_cpu(rsp->logical_block_size); + dev->physical_block_size = le16_to_cpu(rsp->physical_block_size); + dev->max_write_same_sectors = le32_to_cpu(rsp->max_write_same_sectors); + dev->max_discard_sectors = le32_to_cpu(rsp->max_discard_sectors); + dev->discard_granularity = le32_to_cpu(rsp->discard_granularity); + dev->discard_alignment = le32_to_cpu(rsp->discard_alignment); + dev->secure_discard = le16_to_cpu(rsp->secure_discard); + dev->rotational = rsp->rotational; + dev->remote_io_mode = rsp->io_mode; + + dev->max_hw_sectors = sess->max_io_size / dev->logical_block_size; + dev->max_segments = BMAX_SEGMENTS; + + if (dev->remote_io_mode == IBNBD_BLOCKIO) { + dev->max_hw_sectors = min_t(u32, dev->max_hw_sectors, + le32_to_cpu(rsp->max_hw_sectors)); + dev->max_segments = min_t(u16, dev->max_segments, + le16_to_cpu(rsp->max_segments)); + } + + return 0; +} + +static int ibnbd_clt_revalidate_disk(struct ibnbd_clt_dev *dev, + size_t new_nsectors) +{ + int err = 0; + + ibnbd_info(dev, "Device size changed from %zu to %zu sectors\n", + dev->nsectors, new_nsectors); + dev->nsectors = new_nsectors; + set_capacity(dev->gd, + dev->nsectors * (dev->logical_block_size / + KERNEL_SECTOR_SIZE)); + err = revalidate_disk(dev->gd); + if (err) + ibnbd_err(dev, "Failed to change device size from" + " %zu to %zu, err: %d\n", dev->nsectors, + new_nsectors, err); + return err; +} + +static int process_msg_open_rsp(struct ibnbd_clt_dev *dev, + struct ibnbd_msg_open_rsp *rsp) +{ + int err = 0; + + mutex_lock(&dev->lock); + if (dev->dev_state == DEV_STATE_UNMAPPED) { + ibnbd_info(dev, "Ignoring Open-Response message from server for " + " unmapped device\n"); + err = -ENOENT; + goto out; + } + if (dev->dev_state == DEV_STATE_MAPPED_DISCONNECTED) { + u64 nsectors = le64_to_cpu(rsp->nsectors); + + /* + * If the device was remapped and the size changed in the + * meantime we need to revalidate it + */ + if (dev->nsectors != nsectors) + ibnbd_clt_revalidate_disk(dev, nsectors); + ibnbd_info(dev, "Device online, device remapped successfully\n"); + } + err = ibnbd_clt_set_dev_attr(dev, rsp); + if (unlikely(err)) + goto out; + dev->dev_state = DEV_STATE_MAPPED; + +out: + mutex_unlock(&dev->lock); + + return err; +} + +int ibnbd_clt_resize_disk(struct ibnbd_clt_dev *dev, size_t newsize) +{ + int ret = 0; + + mutex_lock(&dev->lock); + if (dev->dev_state != DEV_STATE_MAPPED) { + pr_err("Failed to set new size of the device, " + "device is not opened\n"); + ret = -ENOENT; + goto out; + } + ret = ibnbd_clt_revalidate_disk(dev, newsize); + +out: + mutex_unlock(&dev->lock); + + return ret; +} + +static inline void ibnbd_clt_dev_requeue(struct ibnbd_queue *q) +{ + if (WARN_ON(!q->hctx)) + return; + + /* We can come here from interrupt, thus async=true */ + blk_mq_run_hw_queue(q->hctx, true); +} + +enum { + IBNBD_DELAY_10ms = 10, + IBNBD_DELAY_IFBUSY = -1, +}; + +/** + * ibnbd_get_cpu_qlist() - finds a list with HW queues to be requeued + * + * Description: + * Each CPU has a list of HW queues, which needs to be requeed. If a list + * is not empty - it is marked with a bit. This function finds first + * set bit in a bitmap and returns corresponding CPU list. + */ +static struct ibnbd_cpu_qlist * +ibnbd_get_cpu_qlist(struct ibnbd_clt_session *sess, int cpu) +{ + int bit; + + /* First half */ + bit = find_next_bit(sess->cpu_queues_bm, nr_cpu_ids, cpu); + if (bit < nr_cpu_ids) { + return per_cpu_ptr(sess->cpu_queues, bit); + } else if (cpu != 0) { + /* Second half */ + bit = find_next_bit(sess->cpu_queues_bm, cpu, 0); + if (bit < cpu) + return per_cpu_ptr(sess->cpu_queues, bit); + } + + return NULL; +} + +static inline int nxt_cpu(int cpu) +{ + return (cpu + 1) % nr_cpu_ids; +} + +/** + * ibnbd_requeue_if_needed() - requeue if CPU queue is marked as non empty + * + * Description: + * Each CPU has it's own list of HW queues, which should be requeued. + * Function finds such list with HW queues, takes a list lock, picks up + * the first HW queue out of the list and requeues it. + * + * Return: + * True if the queue was requeued, false otherwise. + * + * Context: + * Does not matter. + */ +static inline bool ibnbd_requeue_if_needed(struct ibnbd_clt_session *sess) +{ + struct ibnbd_queue *q = NULL; + struct ibnbd_cpu_qlist *cpu_q; + unsigned long flags; + int *cpup; + + /* + * To keep fairness and not to let other queues starve we always + * try to wake up someone else in round-robin manner. That of course + * increases latency but queues always have a chance to be executed. + */ + cpup = get_cpu_ptr(sess->cpu_rr); + for (cpu_q = ibnbd_get_cpu_qlist(sess, nxt_cpu(*cpup)); cpu_q; + cpu_q = ibnbd_get_cpu_qlist(sess, nxt_cpu(cpu_q->cpu))) { + if (!spin_trylock_irqsave(&cpu_q->requeue_lock, flags)) + continue; + if (likely(test_bit(cpu_q->cpu, sess->cpu_queues_bm))) { + q = list_first_entry_or_null(&cpu_q->requeue_list, + typeof(*q), requeue_list); + if (WARN_ON(!q)) + goto clear_bit; + list_del_init(&q->requeue_list); + clear_bit_unlock(0, &q->in_list); + + if (list_empty(&cpu_q->requeue_list)) { + /* Clear bit if nothing is left */ +clear_bit: + clear_bit(cpu_q->cpu, sess->cpu_queues_bm); + } + } + spin_unlock_irqrestore(&cpu_q->requeue_lock, flags); + + if (q) + break; + } + + /** + * Saves the CPU that is going to be requeued on the per-cpu var. Just + * incrementing it doesn't work because ibnbd_get_cpu_qlist() will + * always return the first CPU with something on the queue list when the + * value stored on the var is greater than the last CPU with something + * on the list. + */ + if (cpu_q) + *cpup = cpu_q->cpu; + put_cpu_var(sess->cpu_rr); + + if (q) + ibnbd_clt_dev_requeue(q); + + return !!q; +} + +/** + * ibnbd_requeue_all_if_idle() - requeue all queues left in the list if + * session is idling (there are no requests in-flight). + * + * Description: + * This function tries to rerun all stopped queues if there are no + * requests in-flight anymore. This function tries to solve an obvious + * problem, when number of tags < than number of queues (hctx), which + * are stopped and put to sleep. If last tag, which has been just put, + * does not wake up all left queues (hctxs), IO requests hang forever. + * + * That can happen when all number of tags, say N, have been exhausted + * from one CPU, and we have many block devices per session, say M. + * Each block device has it's own queue (hctx) for each CPU, so eventually + * we can put that number of queues (hctxs) to sleep: M x nr_cpu_ids. + * If number of tags N < M x nr_cpu_ids finally we will get an IO hang. + * + * To avoid this hang last caller of ibnbd_put_tag() (last caller is the + * one who observes sess->busy == 0) must wake up all remaining queues. + * + * Context: + * Does not matter. + */ +static inline void ibnbd_requeue_all_if_idle(struct ibnbd_clt_session *sess) +{ + bool requeued; + + do { + requeued = ibnbd_requeue_if_needed(sess); + } while (atomic_read(&sess->busy) == 0 && requeued); +} + +static struct ibtrs_tag *ibnbd_get_tag(struct ibnbd_clt_session *sess, + enum ibtrs_clt_con_type con_type, + int wait) +{ + struct ibtrs_tag *tag; + + tag = ibtrs_clt_get_tag(sess->ibtrs, con_type, + wait ? IBTRS_TAG_WAIT : IBTRS_TAG_NOWAIT); + if (likely(tag)) + /* We have a subtle rare case here, when all tags can be + * consumed before busy counter increased. This is safe, + * because loser will get NULL as a tag, observe 0 busy + * counter and immediately restart the queue himself. + */ + atomic_inc(&sess->busy); + + return tag; +} + +static void ibnbd_put_tag(struct ibnbd_clt_session *sess, struct ibtrs_tag *tag) +{ + ibtrs_clt_put_tag(sess->ibtrs, tag); + atomic_dec(&sess->busy); + /* Paired with ibnbd_clt_dev_add_to_requeue(). Decrement first + * and then check queue bits. + */ + smp_mb__after_atomic(); + ibnbd_requeue_all_if_idle(sess); +} + +static struct ibnbd_iu *ibnbd_get_iu(struct ibnbd_clt_session *sess, + enum ibtrs_clt_con_type con_type, + int wait) +{ + struct ibnbd_iu *iu; + struct ibtrs_tag *tag; + + tag = ibnbd_get_tag(sess, con_type, + wait ? IBTRS_TAG_WAIT : IBTRS_TAG_NOWAIT); + if (unlikely(!tag)) + return NULL; + iu = ibtrs_tag_to_pdu(tag); + iu->tag = tag; /* yes, ibtrs_tag_from_pdu() can be nice here, + * but also we have to think about MQ mode + */ + + return iu; +} + +static void ibnbd_put_iu(struct ibnbd_clt_session *sess, struct ibnbd_iu *iu) +{ + ibnbd_put_tag(sess, iu->tag); +} + +static void ibnbd_softirq_done_fn(struct request *rq) +{ + struct ibnbd_clt_dev *dev = rq->rq_disk->private_data; + struct ibnbd_clt_session *sess = dev->sess; + struct ibnbd_iu *iu; + + iu = blk_mq_rq_to_pdu(rq); + ibnbd_put_tag(sess, iu->tag); + blk_mq_end_request(rq, iu->status); +} + +static void msg_io_conf(void *priv, int errno) +{ + struct ibnbd_iu *iu = (struct ibnbd_iu *)priv; + struct ibnbd_clt_dev *dev = iu->dev; + struct request *rq = iu->rq; + + iu->status = errno ? BLK_STS_IOERR : BLK_STS_OK; + + if (softirq_enable) { + blk_mq_complete_request(rq); + } else { + ibnbd_put_tag(dev->sess, iu->tag); + blk_mq_end_request(rq, iu->status); + } + + if (errno) + ibnbd_info_rl(dev, "%s I/O failed with err: %d\n", + rq_data_dir(rq) == READ ? "read" : "write", + errno); +} + +static void init_iu_comp(struct ibnbd_iu *iu, struct ibnbd_iu_comp *comp) +{ + init_waitqueue_head(&comp->wait); + comp->errno = INT_MAX; + iu->comp = comp; +} + +static void deinit_iu_comp(struct ibnbd_iu *iu) +{ + iu->comp = NULL; +} + +static void wake_up_iu_comp(struct ibnbd_iu *iu, int errno) +{ + struct ibnbd_iu_comp *comp = iu->comp; + + if (comp) { + comp->errno = errno; + wake_up(&comp->wait); + deinit_iu_comp(iu); + } +} + +static void wait_iu_comp(struct ibnbd_iu_comp *comp) +{ + wait_event(comp->wait, comp->errno != INT_MAX); +} + +static void msg_conf(void *priv, int errno) +{ + struct ibnbd_iu *iu = (struct ibnbd_iu *)priv; + + iu->errno = errno; + schedule_work(&iu->work); +} + +enum { + NO_WAIT = 0, + WAIT = 1 +}; + +static int send_usr_msg(struct ibtrs_clt *ibtrs, int dir, + struct ibnbd_iu *iu, struct kvec *vec, size_t nr, + size_t len, struct scatterlist *sg, unsigned int sg_len, + void (*conf)(struct work_struct *work), + int *errno, bool wait) +{ + struct ibnbd_iu_comp comp; + int err; + + if (wait) + init_iu_comp(iu, &comp); + INIT_WORK(&iu->work, conf); + err = ibtrs_clt_request(dir, msg_conf, ibtrs, iu->tag, + iu, vec, nr, len, sg, sg_len); + if (unlikely(err)) { + deinit_iu_comp(iu); + } else if (wait) { + wait_iu_comp(&comp); + *errno = comp.errno; + } else { + *errno = 0; + } + + return err; +} + +static void msg_close_conf(struct work_struct *work) +{ + struct ibnbd_iu *iu = container_of(work, struct ibnbd_iu, work); + struct ibnbd_clt_dev *dev = iu->dev; + + wake_up_iu_comp(iu, iu->errno); + ibnbd_put_iu(dev->sess, iu); + ibnbd_clt_put_dev(dev); +} + +static int send_msg_close(struct ibnbd_clt_dev *dev, u32 device_id, bool wait) +{ + struct ibnbd_clt_session *sess = dev->sess; + struct ibnbd_msg_close msg; + struct ibnbd_iu *iu; + struct kvec vec = { + .iov_base = &msg, + .iov_len = sizeof(msg) + }; + int err, errno; + + iu = ibnbd_get_iu(sess, IBTRS_USR_CON, IBTRS_TAG_WAIT); + if (unlikely(!iu)) + return -ENOMEM; + + iu->buf = NULL; + iu->dev = dev; + + sg_mark_end(&iu->sglist[0]); + + msg.hdr.type = cpu_to_le16(IBNBD_MSG_CLOSE); + msg.device_id = cpu_to_le32(device_id); + + WARN_ON(!ibnbd_clt_get_dev(dev)); + err = send_usr_msg(sess->ibtrs, WRITE, iu, &vec, 1, 0, NULL, 0, + msg_close_conf, &errno, wait); + if (unlikely(err)) { + ibnbd_clt_put_dev(dev); + ibnbd_put_iu(sess, iu); + } else { + err = errno; + } + + return err; +} + +static void msg_open_conf(struct work_struct *work) +{ + struct ibnbd_iu *iu = container_of(work, struct ibnbd_iu, work); + struct ibnbd_msg_open_rsp *rsp = iu->buf; + struct ibnbd_clt_dev *dev = iu->dev; + int errno = iu->errno; + + if (errno) { + ibnbd_err(dev, "Opening failed, server responded: %d\n", errno); + } else { + errno = process_msg_open_rsp(dev, rsp); + if (unlikely(errno)) { + u32 device_id = le32_to_cpu(rsp->device_id); + /* + * If server thinks its fine, but we fail to process + * then be nice and send a close to server. + */ + (void)send_msg_close(dev, device_id, NO_WAIT); + } + } + kfree(rsp); + wake_up_iu_comp(iu, errno); + ibnbd_put_iu(dev->sess, iu); + ibnbd_clt_put_dev(dev); +} + +static void msg_sess_info_conf(struct work_struct *work) +{ + struct ibnbd_iu *iu = container_of(work, struct ibnbd_iu, work); + struct ibnbd_msg_sess_info_rsp *rsp = iu->buf; + struct ibnbd_clt_session *sess = iu->sess; + + if (likely(!iu->errno)) + sess->ver = min_t(u8, rsp->ver, IBNBD_PROTO_VER_MAJOR); + + kfree(rsp); + wake_up_iu_comp(iu, iu->errno); + ibnbd_put_iu(sess, iu); + ibnbd_clt_put_sess(sess); +} + +static int send_msg_open(struct ibnbd_clt_dev *dev, bool wait) +{ + struct ibnbd_clt_session *sess = dev->sess; + struct ibnbd_msg_open_rsp *rsp; + struct ibnbd_msg_open msg; + struct ibnbd_iu *iu; + struct kvec vec = { + .iov_base = &msg, + .iov_len = sizeof(msg) + }; + int err, errno; + + rsp = kzalloc(sizeof(*rsp), GFP_KERNEL); + if (unlikely(!rsp)) + return -ENOMEM; + + iu = ibnbd_get_iu(sess, IBTRS_USR_CON, IBTRS_TAG_WAIT); + if (unlikely(!iu)) { + kfree(rsp); + return -ENOMEM; + } + + iu->buf = rsp; + iu->dev = dev; + + sg_init_one(iu->sglist, rsp, sizeof(*rsp)); + + msg.hdr.type = cpu_to_le16(IBNBD_MSG_OPEN); + msg.access_mode = dev->access_mode; + msg.io_mode = dev->io_mode; + strlcpy(msg.dev_name, dev->pathname, sizeof(msg.dev_name)); + + WARN_ON(!ibnbd_clt_get_dev(dev)); + err = send_usr_msg(sess->ibtrs, READ, iu, + &vec, 1, sizeof(*rsp), iu->sglist, 1, + msg_open_conf, &errno, wait); + if (unlikely(err)) { + ibnbd_clt_put_dev(dev); + ibnbd_put_iu(sess, iu); + kfree(rsp); + } else { + err = errno; + } + + return err; +} + +static int send_msg_sess_info(struct ibnbd_clt_session *sess, bool wait) +{ + struct ibnbd_msg_sess_info_rsp *rsp; + struct ibnbd_msg_sess_info msg; + struct ibnbd_iu *iu; + struct kvec vec = { + .iov_base = &msg, + .iov_len = sizeof(msg) + }; + int err, errno; + + rsp = kzalloc(sizeof(*rsp), GFP_KERNEL); + if (unlikely(!rsp)) + return -ENOMEM; + + iu = ibnbd_get_iu(sess, IBTRS_USR_CON, IBTRS_TAG_WAIT); + if (unlikely(!iu)) { + kfree(rsp); + return -ENOMEM; + } + + iu->buf = rsp; + iu->sess = sess; + + sg_init_one(iu->sglist, rsp, sizeof(*rsp)); + + msg.hdr.type = cpu_to_le16(IBNBD_MSG_SESS_INFO); + msg.ver = IBNBD_PROTO_VER_MAJOR; + + if (unlikely(!ibnbd_clt_get_sess(sess))) { + /* + * That can happen only in one case, when IBTRS has restablished + * the connection and link_ev() is called, but session is almost + * dead, last reference on session is put and caller is waiting + * for IBTRS to close everything. + */ + err = -ENODEV; + goto put_iu; + } + err = send_usr_msg(sess->ibtrs, READ, iu, + &vec, 1, sizeof(*rsp), iu->sglist, 1, + msg_sess_info_conf, &errno, wait); + if (unlikely(err)) { + ibnbd_clt_put_sess(sess); +put_iu: + ibnbd_put_iu(sess, iu); + kfree(rsp); + } else { + err = errno; + } + + return err; +} + +static void set_dev_states_to_disconnected(struct ibnbd_clt_session *sess) +{ + struct ibnbd_clt_dev *dev; + + mutex_lock(&sess->lock); + list_for_each_entry(dev, &sess->devs_list, list) { + ibnbd_err(dev, "Device disconnected.\n"); + + mutex_lock(&dev->lock); + if (dev->dev_state == DEV_STATE_MAPPED) + dev->dev_state = DEV_STATE_MAPPED_DISCONNECTED; + mutex_unlock(&dev->lock); + } + mutex_unlock(&sess->lock); +} + +static void remap_devs(struct ibnbd_clt_session *sess) +{ + struct ibnbd_clt_dev *dev; + struct ibtrs_attrs attrs; + int err; + + /* + * Careful here: we are called from IBTRS link event directly, + * thus we can't send any IBTRS request and wait for response + * or IBTRS will not be able to complete request with failure + * if something goes wrong (failing of outstanding requests + * happens exactly from the context where we are blocking now). + * + * So to avoid deadlocks each usr message sent from here must + * be asynchronous. + */ + + err = send_msg_sess_info(sess, NO_WAIT); + if (unlikely(err)) { + pr_err("send_msg_sess_info(\"%s\"): %d\n", sess->sessname, err); + return; + } + + ibtrs_clt_query(sess->ibtrs, &attrs); + mutex_lock(&sess->lock); + sess->max_io_size = attrs.max_io_size; + + list_for_each_entry(dev, &sess->devs_list, list) { + bool skip; + + mutex_lock(&dev->lock); + skip = (dev->dev_state == DEV_STATE_INIT); + mutex_unlock(&dev->lock); + if (skip) + /* + * When device is establishing connection for the first + * time - do not remap, it will be closed soon. + */ + continue; + + ibnbd_info(dev, "session reconnected, remapping device\n"); + err = send_msg_open(dev, NO_WAIT); + if (unlikely(err)) { + ibnbd_err(dev, "send_msg_open(): %d\n", err); + break; + } + } + mutex_unlock(&sess->lock); +} + +static void ibnbd_clt_link_ev(void *priv, enum ibtrs_clt_link_ev ev) +{ + struct ibnbd_clt_session *sess = priv; + + switch (ev) { + case IBTRS_CLT_LINK_EV_DISCONNECTED: + set_dev_states_to_disconnected(sess); + break; + case IBTRS_CLT_LINK_EV_RECONNECTED: + remap_devs(sess); + break; + default: + pr_err("Unknown session event received (%d), session: %s\n", + ev, sess->sessname); + } +} + +static void ibnbd_init_cpu_qlists(struct ibnbd_cpu_qlist __percpu *cpu_queues) +{ + unsigned int cpu; + struct ibnbd_cpu_qlist *cpu_q; + + for_each_possible_cpu(cpu) { + cpu_q = per_cpu_ptr(cpu_queues, cpu); + + cpu_q->cpu = cpu; + INIT_LIST_HEAD(&cpu_q->requeue_list); + spin_lock_init(&cpu_q->requeue_lock); + } +} + +static struct blk_mq_ops ibnbd_mq_ops; +static int setup_mq_tags(struct ibnbd_clt_session *sess) +{ + struct blk_mq_tag_set *tags = &sess->tag_set; + + memset(tags, 0, sizeof(*tags)); + tags->ops = &ibnbd_mq_ops; + tags->queue_depth = sess->queue_depth; + tags->numa_node = NUMA_NO_NODE; + tags->flags = BLK_MQ_F_SHOULD_MERGE | + BLK_MQ_F_SG_MERGE | + BLK_MQ_F_TAG_SHARED; + tags->cmd_size = sizeof(struct ibnbd_iu); + tags->nr_hw_queues = num_online_cpus(); + + return blk_mq_alloc_tag_set(tags); +} + +static void destroy_mq_tags(struct ibnbd_clt_session *sess) +{ + if (sess->tag_set.tags) + blk_mq_free_tag_set(&sess->tag_set); +} + +static inline void wake_up_ibtrs_waiters(struct ibnbd_clt_session *sess) +{ + /* paired with rmb() in wait_for_ibtrs_connection() */ + smp_wmb(); + sess->ibtrs_ready = true; + wake_up_all(&sess->ibtrs_waitq); +} + +static void close_ibtrs(struct ibnbd_clt_session *sess) +{ + might_sleep(); + + if (!IS_ERR_OR_NULL(sess->ibtrs)) { + ibtrs_clt_close(sess->ibtrs); + sess->ibtrs = NULL; + wake_up_ibtrs_waiters(sess); + } +} + +static void free_sess(struct ibnbd_clt_session *sess) +{ + WARN_ON(!list_empty(&sess->devs_list)); + + might_sleep(); + + close_ibtrs(sess); + destroy_mq_tags(sess); + if (!list_empty(&sess->list)) { + mutex_lock(&sess_lock); + list_del(&sess->list); + mutex_unlock(&sess_lock); + } + free_percpu(sess->cpu_queues); + free_percpu(sess->cpu_rr); + kfree(sess); +} + +static struct ibnbd_clt_session *alloc_sess(const char *sessname, + const struct ibtrs_addr *paths, + size_t path_cnt) +{ + struct ibnbd_clt_session *sess; + int err, cpu; + + sess = kzalloc_node(sizeof(*sess), GFP_KERNEL, NUMA_NO_NODE); + if (unlikely(!sess)) { + pr_err("Failed to create session %s," + " allocating session struct failed\n", sessname); + return ERR_PTR(-ENOMEM); + } + strlcpy(sess->sessname, sessname, sizeof(sess->sessname)); + atomic_set(&sess->busy, 0); + mutex_init(&sess->lock); + INIT_LIST_HEAD(&sess->devs_list); + INIT_LIST_HEAD(&sess->list); + bitmap_zero(sess->cpu_queues_bm, NR_CPUS); + init_waitqueue_head(&sess->ibtrs_waitq); + refcount_set(&sess->refcount, 1); + + sess->cpu_queues = alloc_percpu(struct ibnbd_cpu_qlist); + if (unlikely(!sess->cpu_queues)) { + pr_err("Failed to create session to %s," + " alloc of percpu var (cpu_queues) failed\n", sessname); + err = -ENOMEM; + goto err; + } + ibnbd_init_cpu_qlists(sess->cpu_queues); + + /** + * That is simple percpu variable which stores cpu indeces, which are + * incremented on each access. We need that for the sake of fairness + * to wake up queues in a round-robin manner. + */ + sess->cpu_rr = alloc_percpu(int); + if (unlikely(!sess->cpu_rr)) { + pr_err("Failed to create session %s," + " alloc of percpu var (cpu_rr) failed\n", sessname); + err = -ENOMEM; + goto err; + } + for_each_possible_cpu(cpu) + *per_cpu_ptr(sess->cpu_rr, cpu) = cpu; + + return sess; + +err: + free_sess(sess); + + return ERR_PTR(err); +} + +static int wait_for_ibtrs_connection(struct ibnbd_clt_session *sess) +{ + wait_event(sess->ibtrs_waitq, sess->ibtrs_ready); + /* paired with wmb() in wake_up_ibtrs_waiters() */ + smp_rmb(); + if (unlikely(IS_ERR_OR_NULL(sess->ibtrs))) + return -ECONNRESET; + + return 0; +} + +static void wait_for_ibtrs_disconnection(struct ibnbd_clt_session *sess) +__releases(&sess_lock) +__acquires(&sess_lock) +{ + DEFINE_WAIT_FUNC(wait, autoremove_wake_function); + + prepare_to_wait(&sess->ibtrs_waitq, &wait, TASK_UNINTERRUPTIBLE); + if (IS_ERR_OR_NULL(sess->ibtrs)) { + finish_wait(&sess->ibtrs_waitq, &wait); + return; + } + mutex_unlock(&sess_lock); + /* After unlock session can be freed, so careful */ + schedule(); + mutex_lock(&sess_lock); +} + +static struct ibnbd_clt_session *__find_and_get_sess(const char *sessname) +__releases(&sess_lock) +__acquires(&sess_lock) +{ + struct ibnbd_clt_session *sess; + int err; + +again: + list_for_each_entry(sess, &sess_list, list) { + if (strcmp(sessname, sess->sessname)) + continue; + + if (unlikely(sess->ibtrs_ready && IS_ERR_OR_NULL(sess->ibtrs))) + /* + * No IBTRS connection, session is dying. + */ + continue; + + if (likely(ibnbd_clt_get_sess(sess))) { + /* + * Alive session is found, wait for IBTRS connection. + */ + mutex_unlock(&sess_lock); + err = wait_for_ibtrs_connection(sess); + if (unlikely(err)) + ibnbd_clt_put_sess(sess); + mutex_lock(&sess_lock); + + if (unlikely(err)) + /* Session is dying, repeat the loop */ + goto again; + + return sess; + } else { + /* + * Ref is 0, session is dying, wait for IBTRS disconnect + * in order to avoid session names clashes. + */ + wait_for_ibtrs_disconnection(sess); + /* + * IBTRS is disconnected and soon session will be freed, + * so repeat a loop. + */ + goto again; + } + } + + return NULL; +} + +static struct ibnbd_clt_session *find_and_get_sess(const char *sessname) +{ + struct ibnbd_clt_session *sess; + + mutex_lock(&sess_lock); + sess = __find_and_get_sess(sessname); + mutex_unlock(&sess_lock); + + return sess; +} + +static struct ibnbd_clt_session * +find_and_get_or_insert_sess(struct ibnbd_clt_session *sess) +{ + struct ibnbd_clt_session *found; + + mutex_lock(&sess_lock); + found = __find_and_get_sess(sess->sessname); + if (!found) + list_add(&sess->list, &sess_list); + mutex_unlock(&sess_lock); + + return found; +} + +static struct ibnbd_clt_session * +find_and_get_or_create_sess(const char *sessname, + const struct ibtrs_addr *paths, + size_t path_cnt) +{ + struct ibnbd_clt_session *sess, *found; + struct ibtrs_attrs attrs; + int err; + + sess = find_and_get_sess(sessname); + if (sess) + return sess; + + sess = alloc_sess(sessname, paths, path_cnt); + if (unlikely(IS_ERR(sess))) + return sess; + + found = find_and_get_or_insert_sess(sess); + if (unlikely(found)) { + free_sess(sess); + + return found; + } + /* + * Nothing was found, establish ibtrs connection and proceed further. + */ + sess->ibtrs = ibtrs_clt_open(sess, ibnbd_clt_link_ev, sessname, + paths, path_cnt, IBTRS_PORT, + sizeof(struct ibnbd_iu), + RECONNECT_DELAY, BMAX_SEGMENTS, + MAX_RECONNECTS); + if (unlikely(IS_ERR(sess->ibtrs))) { + err = PTR_ERR(sess->ibtrs); + goto wake_up_and_put; + } + ibtrs_clt_query(sess->ibtrs, &attrs); + sess->max_io_size = attrs.max_io_size; + sess->queue_depth = attrs.queue_depth; + + err = setup_mq_tags(sess); + if (unlikely(err)) + goto close_ibtrs; + + err = send_msg_sess_info(sess, WAIT); + if (unlikely(err)) + goto close_ibtrs; + + wake_up_ibtrs_waiters(sess); + + return sess; + +close_ibtrs: + close_ibtrs(sess); +put_sess: + ibnbd_clt_put_sess(sess); + + return ERR_PTR(err); + +wake_up_and_put: + wake_up_ibtrs_waiters(sess); + goto put_sess; +} + +static int ibnbd_client_open(struct block_device *block_device, fmode_t mode) +{ + struct ibnbd_clt_dev *dev = block_device->bd_disk->private_data; + + if (dev->read_only && (mode & FMODE_WRITE)) + return -EPERM; + + if (dev->dev_state == DEV_STATE_UNMAPPED || + !ibnbd_clt_get_dev(dev)) + return -EIO; + + return 0; +} + +static void ibnbd_client_release(struct gendisk *gen, fmode_t mode) +{ + struct ibnbd_clt_dev *dev = gen->private_data; + + ibnbd_clt_put_dev(dev); +} + +static int ibnbd_client_getgeo(struct block_device *block_device, + struct hd_geometry *geo) +{ + u64 size; + struct ibnbd_clt_dev *dev; + + dev = block_device->bd_disk->private_data; + size = dev->size * (dev->logical_block_size / KERNEL_SECTOR_SIZE); + geo->cylinders = (size & ~0x3f) >> 6; /* size/64 */ + geo->heads = 4; + geo->sectors = 16; + geo->start = 0; + + return 0; +} + +static const struct block_device_operations ibnbd_client_ops = { + .owner = THIS_MODULE, + .open = ibnbd_client_open, + .release = ibnbd_client_release, + .getgeo = ibnbd_client_getgeo +}; + +static size_t ibnbd_clt_get_sg_size(struct scatterlist *sglist, u32 len) +{ + struct scatterlist *sg; + size_t tsize = 0; + int i; + + for_each_sg(sglist, sg, len, i) + tsize += sg->length; + return tsize; +} + +static int ibnbd_client_xfer_request(struct ibnbd_clt_dev *dev, + struct request *rq, + struct ibnbd_iu *iu) +{ + struct ibtrs_clt *ibtrs = dev->sess->ibtrs; + struct ibtrs_tag *tag = iu->tag; + struct ibnbd_msg_io msg; + unsigned int sg_cnt = 0; + struct kvec vec; + size_t size; + int err; + + iu->rq = rq; + iu->dev = dev; + msg.sector = cpu_to_le64(blk_rq_pos(rq)); + msg.bi_size = cpu_to_le32(blk_rq_bytes(rq)); + msg.rw = cpu_to_le32(rq_to_ibnbd_flags(rq)); + + /* We only support discards with single segment for now. See queue limits. */ + if (req_op(rq) != REQ_OP_DISCARD) + sg_cnt = blk_rq_map_sg(dev->queue, rq, iu->sglist); + + if (sg_cnt == 0) + /* Do not forget to mark the end */ + sg_mark_end(&iu->sglist[0]); + + msg.hdr.type = cpu_to_le16(IBNBD_MSG_IO); + msg.device_id = cpu_to_le32(dev->device_id); + + vec = (struct kvec) { + .iov_base = &msg, + .iov_len = sizeof(msg) + }; + + size = ibnbd_clt_get_sg_size(iu->sglist, sg_cnt); + err = ibtrs_clt_request(rq_data_dir(rq), msg_io_conf, ibtrs, tag, + iu, &vec, 1, size, iu->sglist, sg_cnt); + if (unlikely(err)) { + ibnbd_err_rl(dev, "IBTRS failed to transfer IO, err: %d\n", + err); + return err; + } + + return 0; +} + +/** + * ibnbd_clt_dev_add_to_requeue() - add device to requeue if session is busy + * + * Description: + * If session is busy, that means someone will requeue us when resources + * are freed. If session is not doing anything - device is not added to + * the list and @false is returned. + */ +static inline bool ibnbd_clt_dev_add_to_requeue(struct ibnbd_clt_dev *dev, + struct ibnbd_queue *q) +{ + struct ibnbd_clt_session *sess = dev->sess; + struct ibnbd_cpu_qlist *cpu_q; + unsigned long flags; + bool added = true; + bool need_set; + + cpu_q = get_cpu_ptr(sess->cpu_queues); + spin_lock_irqsave(&cpu_q->requeue_lock, flags); + + if (likely(!test_and_set_bit_lock(0, &q->in_list))) { + if (WARN_ON(!list_empty(&q->requeue_list))) + goto unlock; + + need_set = !test_bit(cpu_q->cpu, sess->cpu_queues_bm); + if (need_set) { + set_bit(cpu_q->cpu, sess->cpu_queues_bm); + /* Paired with ibnbd_put_tag(). Set a bit first + * and then observe the busy counter. + */ + smp_mb__before_atomic(); + } + if (likely(atomic_read(&sess->busy))) { + list_add_tail(&q->requeue_list, &cpu_q->requeue_list); + } else { + /* Very unlikely, but possible: busy counter was + * observed as zero. Drop all bits and return + * false to restart the queue by ourselves. + */ + if (need_set) + clear_bit(cpu_q->cpu, sess->cpu_queues_bm); + clear_bit_unlock(0, &q->in_list); + added = false; + } + } +unlock: + spin_unlock_irqrestore(&cpu_q->requeue_lock, flags); + put_cpu_ptr(sess->cpu_queues); + + return added; +} + +static void ibnbd_clt_dev_kick_mq_queue(struct ibnbd_clt_dev *dev, + struct blk_mq_hw_ctx *hctx, + int delay) +{ + struct ibnbd_queue *q = hctx->driver_data; + + if (delay != IBNBD_DELAY_IFBUSY) + blk_mq_delay_run_hw_queue(hctx, delay); + else if (unlikely(!ibnbd_clt_dev_add_to_requeue(dev, q))) + /* + * If session is not busy we have to restart + * the queue ourselves. + */ + blk_mq_delay_run_hw_queue(hctx, IBNBD_DELAY_10ms); +} + +static blk_status_t ibnbd_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + struct request *rq = bd->rq; + struct ibnbd_clt_dev *dev = rq->rq_disk->private_data; + struct ibnbd_iu *iu = blk_mq_rq_to_pdu(rq); + int err; + + if (unlikely(!ibnbd_clt_dev_is_mapped(dev))) + return BLK_STS_IOERR; + + iu->tag = ibnbd_get_tag(dev->sess, IBTRS_IO_CON, IBTRS_TAG_NOWAIT); + if (unlikely(!iu->tag)) { + ibnbd_clt_dev_kick_mq_queue(dev, hctx, IBNBD_DELAY_IFBUSY); + return BLK_STS_RESOURCE; + } + + blk_mq_start_request(rq); + err = ibnbd_client_xfer_request(dev, rq, iu); + if (likely(err == 0)) + return BLK_STS_OK; + if (unlikely(err == -EAGAIN || err == -ENOMEM)) { + ibnbd_clt_dev_kick_mq_queue(dev, hctx, IBNBD_DELAY_10ms); + ibnbd_put_tag(dev->sess, iu->tag); + return BLK_STS_RESOURCE; + } + + ibnbd_put_tag(dev->sess, iu->tag); + return BLK_STS_IOERR; +} + +static int ibnbd_init_request(struct blk_mq_tag_set *set, struct request *rq, + unsigned int hctx_idx, unsigned int numa_node) +{ + struct ibnbd_iu *iu = blk_mq_rq_to_pdu(rq); + + sg_init_table(iu->sglist, BMAX_SEGMENTS); + return 0; +} + +static inline void ibnbd_init_hw_queue(struct ibnbd_clt_dev *dev, + struct ibnbd_queue *q, + struct blk_mq_hw_ctx *hctx) +{ + INIT_LIST_HEAD(&q->requeue_list); + q->dev = dev; + q->hctx = hctx; +} + +static void ibnbd_init_mq_hw_queues(struct ibnbd_clt_dev *dev) +{ + int i; + struct blk_mq_hw_ctx *hctx; + struct ibnbd_queue *q; + + queue_for_each_hw_ctx(dev->queue, hctx, i) { + q = &dev->hw_queues[i]; + ibnbd_init_hw_queue(dev, q, hctx); + hctx->driver_data = q; + } +} + +static struct blk_mq_ops ibnbd_mq_ops = { + .queue_rq = ibnbd_queue_rq, + .init_request = ibnbd_init_request, + .complete = ibnbd_softirq_done_fn, +}; + +static int index_to_minor(int index) +{ + return index << IBNBD_PART_BITS; +} + +static int minor_to_index(int minor) +{ + return minor >> IBNBD_PART_BITS; +} + +static int setup_mq_dev(struct ibnbd_clt_dev *dev) +{ + dev->queue = blk_mq_init_queue(&dev->sess->tag_set); + if (IS_ERR(dev->queue)) { + ibnbd_err(dev, + "Initializing multiqueue queue failed, err: %ld\n", + PTR_ERR(dev->queue)); + return PTR_ERR(dev->queue); + } + ibnbd_init_mq_hw_queues(dev); + return 0; +} + +static void setup_request_queue(struct ibnbd_clt_dev *dev) +{ + blk_queue_logical_block_size(dev->queue, dev->logical_block_size); + blk_queue_physical_block_size(dev->queue, dev->physical_block_size); + blk_queue_max_hw_sectors(dev->queue, dev->max_hw_sectors); + blk_queue_max_write_same_sectors(dev->queue, + dev->max_write_same_sectors); + + /* we don't support discards to "discontiguous" segments in on request */ + blk_queue_max_discard_segments(dev->queue, 1); + + blk_queue_max_discard_sectors(dev->queue, dev->max_discard_sectors); + dev->queue->limits.discard_granularity = dev->discard_granularity; + dev->queue->limits.discard_alignment = dev->discard_alignment; + if (dev->max_discard_sectors) + blk_queue_flag_set(QUEUE_FLAG_DISCARD, dev->queue); + if (dev->secure_discard) + blk_queue_flag_set(QUEUE_FLAG_SECERASE, dev->queue); + + blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, dev->queue); + blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, dev->queue); + /* our hca only support 32 sg cnt, proto use one, so 31 left */ + blk_queue_max_segments(dev->queue, dev->max_segments); + blk_queue_io_opt(dev->queue, dev->sess->max_io_size); + blk_queue_virt_boundary(dev->queue, 4095); + blk_queue_write_cache(dev->queue, true, true); + dev->queue->queuedata = dev; +} + +static void ibnbd_clt_setup_gen_disk(struct ibnbd_clt_dev *dev, int idx) +{ + dev->gd->major = ibnbd_client_major; + dev->gd->first_minor = index_to_minor(idx); + dev->gd->fops = &ibnbd_client_ops; + dev->gd->queue = dev->queue; + dev->gd->private_data = dev; + snprintf(dev->gd->disk_name, sizeof(dev->gd->disk_name), "ibnbd%d", + idx); + pr_debug("disk_name=%s, capacity=%zu\n", + dev->gd->disk_name, + dev->nsectors * (dev->logical_block_size / KERNEL_SECTOR_SIZE) + ); + + set_capacity(dev->gd, dev->nsectors * (dev->logical_block_size / + KERNEL_SECTOR_SIZE)); + + if (dev->access_mode == IBNBD_ACCESS_RO) { + dev->read_only = true; + set_disk_ro(dev->gd, true); + } else { + dev->read_only = false; + } + + if (!dev->rotational) + blk_queue_flag_set(QUEUE_FLAG_NONROT, dev->queue); +} + +static void ibnbd_clt_add_gen_disk(struct ibnbd_clt_dev *dev) +{ + add_disk(dev->gd); +} + +static int ibnbd_client_setup_device(struct ibnbd_clt_session *sess, + struct ibnbd_clt_dev *dev, int idx) +{ + int err; + + dev->size = dev->nsectors * dev->logical_block_size; + + err = setup_mq_dev(dev); + if (err) + return err; + + setup_request_queue(dev); + + dev->gd = alloc_disk_node(1 << IBNBD_PART_BITS, NUMA_NO_NODE); + if (!dev->gd) { + ibnbd_err(dev, "Failed to allocate disk node\n"); + blk_cleanup_queue(dev->queue); + return -ENOMEM; + } + + ibnbd_clt_setup_gen_disk(dev, idx); + + return 0; +} + +static struct ibnbd_clt_dev *init_dev(struct ibnbd_clt_session *sess, + enum ibnbd_access_mode access_mode, + enum ibnbd_io_mode io_mode, + const char *pathname) +{ + struct ibnbd_clt_dev *dev; + int ret; + + dev = kzalloc_node(sizeof(*dev), GFP_KERNEL, NUMA_NO_NODE); + if (!dev) + return ERR_PTR(-ENOMEM); + + dev->hw_queues = kcalloc(nr_cpu_ids, sizeof(*dev->hw_queues), GFP_KERNEL); + if (unlikely(!dev->hw_queues)) { + pr_err("Failed to initialize device '%s' from session" + " %s, allocating hw_queues failed.", pathname, + sess->sessname); + ret = -ENOMEM; + goto out_alloc; + } + + mutex_lock(&ida_lock); + ret = ida_simple_get(&index_ida, 0, minor_to_index(1 << MINORBITS), + GFP_KERNEL); + mutex_unlock(&ida_lock); + if (ret < 0) { + pr_err("Failed to initialize device '%s' from session %s," + " allocating idr failed, err: %d\n", pathname, + sess->sessname, ret); + goto out_queues; + } + dev->clt_device_id = ret; + dev->sess = sess; + dev->access_mode = access_mode; + dev->io_mode = io_mode; + strlcpy(dev->pathname, pathname, sizeof(dev->pathname)); + mutex_init(&dev->lock); + refcount_set(&dev->refcount, 1); + dev->dev_state = DEV_STATE_INIT; + + /* + * Here we called from sysfs entry, thus clt-sysfs is + * responsible that session will not disappear. + */ + WARN_ON(!ibnbd_clt_get_sess(sess)); + + return dev; + +out_queues: + kfree(dev->hw_queues); +out_alloc: + kfree(dev); + return ERR_PTR(ret); +} + +static bool __exists_dev(const char *pathname) +{ + struct ibnbd_clt_session *sess; + struct ibnbd_clt_dev *dev; + bool found = false; + + list_for_each_entry(sess, &sess_list, list) { + mutex_lock(&sess->lock); + list_for_each_entry(dev, &sess->devs_list, list) { + if (!strncmp(dev->pathname, pathname, + sizeof(dev->pathname))) { + found = true; + break; + } + } + mutex_unlock(&sess->lock); + if (found) + break; + } + + return found; +} + +static bool exists_devpath(const char *pathname) +{ + bool found; + + mutex_lock(&sess_lock); + found = __exists_dev(pathname); + mutex_unlock(&sess_lock); + + return found; +} + +static bool insert_dev_if_not_exists_devpath(const char *pathname, + struct ibnbd_clt_session *sess, + struct ibnbd_clt_dev *dev) +{ + bool found; + + mutex_lock(&sess_lock); + found = __exists_dev(pathname); + if (!found) { + mutex_lock(&sess->lock); + list_add_tail(&dev->list, &sess->devs_list); + mutex_unlock(&sess->lock); + } + mutex_unlock(&sess_lock); + + return found; +} + +static void delete_dev(struct ibnbd_clt_dev *dev) +{ + struct ibnbd_clt_session *sess = dev->sess; + + mutex_lock(&sess->lock); + list_del(&dev->list); + mutex_unlock(&sess->lock); +} + +struct ibnbd_clt_dev *ibnbd_clt_map_device(const char *sessname, + struct ibtrs_addr *paths, + size_t path_cnt, + const char *pathname, + enum ibnbd_access_mode access_mode, + enum ibnbd_io_mode io_mode) +{ + struct ibnbd_clt_session *sess; + struct ibnbd_clt_dev *dev; + int ret; + + if (unlikely(exists_devpath(pathname))) + return ERR_PTR(-EEXIST); + + sess = find_and_get_or_create_sess(sessname, paths, path_cnt); + if (unlikely(IS_ERR(sess))) + return ERR_CAST(sess); + + dev = init_dev(sess, access_mode, io_mode, pathname); + if (unlikely(IS_ERR(dev))) { + pr_err("map_device: failed to map device '%s' from session %s," + " can't initialize device, err: %ld\n", pathname, + sess->sessname, PTR_ERR(dev)); + ret = PTR_ERR(dev); + goto put_sess; + } + if (unlikely(insert_dev_if_not_exists_devpath(pathname, sess, dev))) { + ret = -EEXIST; + goto put_dev; + } + ret = send_msg_open(dev, WAIT); + if (unlikely(ret)) { + ibnbd_err(dev, "map_device: failed, can't open remote device," + " err: %d\n", ret); + goto del_dev; + } + mutex_lock(&dev->lock); + pr_debug("Opened remote device: session=%s, path='%s'\n", + sess->sessname, pathname); + ret = ibnbd_client_setup_device(sess, dev, dev->clt_device_id); + if (ret) { + ibnbd_err(dev, "map_device: Failed to configure device, err: %d\n", + ret); + mutex_unlock(&dev->lock); + goto del_dev; + } + + ibnbd_info(dev, "map_device: Device mapped as %s (nsectors: %zu," + " logical_block_size: %d, physical_block_size: %d," + " max_write_same_sectors: %d, max_discard_sectors: %d," + " discard_granularity: %d, discard_alignment: %d, " + "secure_discard: %d, max_segments: %d, max_hw_sectors: %d, " + "rotational: %d)\n", + dev->gd->disk_name, dev->nsectors, dev->logical_block_size, + dev->physical_block_size, dev->max_write_same_sectors, + dev->max_discard_sectors, dev->discard_granularity, + dev->discard_alignment, dev->secure_discard, + dev->max_segments, dev->max_hw_sectors, dev->rotational); + + mutex_unlock(&dev->lock); + + ibnbd_clt_add_gen_disk(dev); + ibnbd_clt_put_sess(sess); + + return dev; + +del_dev: + delete_dev(dev); +put_dev: + ibnbd_clt_put_dev(dev); +put_sess: + ibnbd_clt_put_sess(sess); + + return ERR_PTR(ret); +} + +static void destroy_gen_disk(struct ibnbd_clt_dev *dev) +{ + del_gendisk(dev->gd); + /* + * Before marking queue as dying (blk_cleanup_queue() does that) + * we have to be sure that everything in-flight has gone. + * Blink with freeze/unfreeze. + */ + blk_mq_freeze_queue(dev->queue); + blk_mq_unfreeze_queue(dev->queue); + blk_cleanup_queue(dev->queue); + put_disk(dev->gd); +} + +static void destroy_sysfs(struct ibnbd_clt_dev *dev, + const struct attribute *sysfs_self) +{ + ibnbd_clt_remove_dev_symlink(dev); + if (dev->kobj.state_initialized) { + if (sysfs_self) + /* To avoid deadlock firstly commit suicide */ + sysfs_remove_file_self(&dev->kobj, sysfs_self); + kobject_del(&dev->kobj); + kobject_put(&dev->kobj); + } +} + +int ibnbd_clt_unmap_device(struct ibnbd_clt_dev *dev, bool force, + const struct attribute *sysfs_self) +{ + struct ibnbd_clt_session *sess = dev->sess; + int refcount, ret = 0; + bool was_mapped; + + mutex_lock(&dev->lock); + if (dev->dev_state == DEV_STATE_UNMAPPED) { + ibnbd_info(dev, "Device is already being unmapped\n"); + ret = -EALREADY; + goto err; + } + refcount = refcount_read(&dev->refcount); + if (!force && refcount > 1) { + ibnbd_err(dev, "Closing device failed, device is in use," + " (%d device users)\n", refcount - 1); + ret = -EBUSY; + goto err; + } + was_mapped = (dev->dev_state == DEV_STATE_MAPPED); + dev->dev_state = DEV_STATE_UNMAPPED; + mutex_unlock(&dev->lock); + + delete_dev(dev); + destroy_sysfs(dev, sysfs_self); + destroy_gen_disk(dev); + if (was_mapped && sess->ibtrs) + send_msg_close(dev, dev->device_id, WAIT); + + ibnbd_info(dev, "Device is unmapped\n"); + + /* Likely last reference put */ + ibnbd_clt_put_dev(dev); + + /* + * Here device and session can be vanished! + */ + + return 0; +err: + mutex_unlock(&dev->lock); + + return ret; +} + +int ibnbd_clt_remap_device(struct ibnbd_clt_dev *dev) +{ + int err; + + mutex_lock(&dev->lock); + if (likely(dev->dev_state == DEV_STATE_MAPPED_DISCONNECTED)) + err = 0; + else if (dev->dev_state == DEV_STATE_UNMAPPED) + err = -ENODEV; + else if (dev->dev_state == DEV_STATE_MAPPED) + err = -EALREADY; + else + err = -EBUSY; + mutex_unlock(&dev->lock); + if (likely(!err)) { + ibnbd_info(dev, "Remapping device.\n"); + err = send_msg_open(dev, WAIT); + if (unlikely(err)) + ibnbd_err(dev, "remap_device: %d\n", err); + } + + return err; +} + +static void unmap_device_work(struct work_struct *work) +{ + struct ibnbd_clt_dev *dev; + + dev = container_of(work, typeof(*dev), unmap_on_rmmod_work); + ibnbd_clt_unmap_device(dev, true, NULL); +} + +static void ibnbd_destroy_sessions(void) +{ + struct ibnbd_clt_session *sess, *sn; + struct ibnbd_clt_dev *dev, *tn; + + /* Firstly forbid access through sysfs interface */ + ibnbd_clt_destroy_default_group(); + ibnbd_clt_destroy_sysfs_files(); + + /* + * Here at this point there is no any concurrent access to sessions + * list and devices list: + * 1. New session or device can'be be created - session sysfs files + * are removed. + * 2. Device or session can't be removed - module reference is taken + * into account in unmap device sysfs callback. + * 3. No IO requests inflight - each file open of block_dev increases + * module reference in get_disk(). + * + * But still there can be user requests inflights, which are sent by + * asynchronous send_msg_*() functions, thus before unmapping devices + * IBTRS session must be explicitly closed. + */ + + list_for_each_entry_safe(sess, sn, &sess_list, list) { + WARN_ON(!ibnbd_clt_get_sess(sess)); + close_ibtrs(sess); + list_for_each_entry_safe(dev, tn, &sess->devs_list, list) { + /* + * Here unmap happens in parallel for only one reason: + * blk_cleanup_queue() takes around half a second, so + * on huge amount of devices the whole module unload + * procedure takes minutes. + */ + INIT_WORK(&dev->unmap_on_rmmod_work, unmap_device_work); + queue_work(unload_wq, &dev->unmap_on_rmmod_work); + } + ibnbd_clt_put_sess(sess); + } + /* Wait for all scheduled unmap works */ + flush_workqueue(unload_wq); + WARN_ON(!list_empty(&sess_list)); +} + +static int __init ibnbd_client_init(void) +{ + int err; + + pr_info("Loading module %s, version %s, proto %s: " + "(softirq_enable: %d)\n", KBUILD_MODNAME, + IBNBD_VER_STRING, IBNBD_PROTO_VER_STRING, + softirq_enable); + + ibnbd_client_major = register_blkdev(ibnbd_client_major, "ibnbd"); + if (ibnbd_client_major <= 0) { + pr_err("Failed to load module," + " block device registration failed\n"); + err = -EBUSY; + goto out; + } + + err = ibnbd_clt_create_sysfs_files(); + if (err) { + pr_err("Failed to load module," + " creating sysfs device files failed, err: %d\n", + err); + goto out_unregister_blk; + } + + unload_wq = alloc_workqueue("ibnbd_unload_wq", WQ_MEM_RECLAIM, 0); + if (!unload_wq) { + pr_err("Failed to load module, alloc ibnbd_unload_wq failed\n"); + goto out_destroy_sysfs_files; + } + + return 0; + +out_destroy_sysfs_files: + ibnbd_clt_destroy_sysfs_files(); +out_unregister_blk: + unregister_blkdev(ibnbd_client_major, "ibnbd"); +out: + return err; +} + +static void __exit ibnbd_client_exit(void) +{ + pr_info("Unloading module\n"); + ibnbd_destroy_sessions(); + unregister_blkdev(ibnbd_client_major, "ibnbd"); + ida_destroy(&index_ida); + destroy_workqueue(unload_wq); + pr_info("Module unloaded\n"); +} + +module_init(ibnbd_client_init); +module_exit(ibnbd_client_exit); -- 2.13.1
