[PATCH 16/24] ibnbd: client: main functionality

Roman Pen
2018-02-02T14:08:56Z

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@profitbricks.com>
Signed-off-by: Danil Kipnis <danil.kipnis@profitbricks.com>
Cc: Jack Wang <jinpu.wang@profitbricks.com>
---
drivers/block/ibnbd/ibnbd-clt.c | 1959 +++++++++++++++++++++++++++++++++++++++
1 file changed, 1959 insertions(+)

diff --git a/drivers/block/ibnbd/ibnbd-clt.c b/drivers/block/ibnbd/ibnbd-clt.c
new file mode 100644
index 000000000000..b5bc71414778
--- /dev/null
+++ b/drivers/block/ibnbd/ibnbd-clt.c
@@ -0,0 +1,1959 @@
+/*
+ * InfiniBand Network Block Driver
+ *
+ * Copyright (c) 2014 - 2017 ProfitBricks GmbH. All rights reserved.
+ * Authors: Fabian Holler <mail@fholler.de>
+ * Jack Wang <jinpu.wang@profitbricks.com>
+ * Kleber Souza <kleber.souza@profitbricks.com>
+ * Danil Kipnis <danil.kipnis@profitbricks.com>
+ * Roman Penyaev <roman.penyaev@profitbricks.com>
+ * Milind Dumbare <Milind.dumbare@gmail.com>
+ *
+ * Copyright (c) 2017 - 2018 ProfitBricks GmbH. All rights reserved.
+ * Authors: Danil Kipnis <danil.kipnis@profitbricks.com>
+ * Roman Penyaev <roman.penyaev@profitbricks.com>
+ *
+ * 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@profitbricks.com");
+MODULE_DESCRIPTION("InfiniBand Network Block Device Client");
+MODULE_VERSION(IBNBD_VER_STRING);
+MODULE_LICENSE("GPL");
+
+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 void ibnbd_clt_set_dev_attr(struct ibnbd_clt_dev *dev,
+ const struct ibnbd_msg_open_rsp *rsp)
+{
+ struct ibnbd_clt_session *sess = dev->sess;
+
+ 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));
+ }
+}
+
+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");
+ }
+ ibnbd_clt_set_dev_attr(dev, rsp);
+ 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 void ibnbd_blk_delay_work(struct work_struct *work)
+{
+ struct ibnbd_clt_dev *dev;
+
+ dev = container_of(work, struct ibnbd_clt_dev, rq_delay_work.work);
+ spin_lock_irq(dev->queue->queue_lock);
+ blk_start_queue(dev->queue);
+ spin_unlock_irq(dev->queue->queue_lock);
+}
+
+/**
+ * What is the difference between this and original blk_delay_queue() ?
+ * Here the stop queue flag is cleared, so we are like MQ.
+ */
+static void ibnbd_blk_delay_queue(struct ibnbd_clt_dev *dev,
+ unsigned long msecs)
+{
+ int cpu = get_cpu();
+
+ kblockd_schedule_delayed_work_on(cpu, &dev->rq_delay_work,
+ msecs_to_jiffies(msecs));
+ put_cpu();
+}
+
+static inline void ibnbd_clt_dev_requeue(struct ibnbd_queue *q)
+{
+ struct ibnbd_clt_dev *dev = q->dev;
+
+ if (dev->queue_mode == BLK_MQ) {
+ if (WARN_ON(!q->hctx))
+ return;
+ blk_mq_delay_queue(q->hctx, 0);
+ } else if (dev->queue_mode == BLK_RQ) {
+ ibnbd_blk_delay_queue(q->dev, 0);
+ } else {
+ WARN(1, "We support requeueing only for RQ or MQ");
+ }
+}
+
+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;
+
+ switch (dev->queue_mode) {
+ case BLK_MQ:
+ iu = blk_mq_rq_to_pdu(rq);
+ ibnbd_put_tag(sess, iu->tag);
+ blk_mq_end_request(rq, iu->status);
+ break;
+ case BLK_RQ:
+ iu = rq->special;
+ blk_end_request_all(rq, iu->status);
+ break;
+ default:
+ WARN(true, "dev->queue_mode , contains unexpected"
+ " value: %d. Memory Corruption? Inflight I/O stalled!\n",
+ dev->queue_mode);
+ return;
+ }
+}
+
+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;
+
+ switch (dev->queue_mode) {
+ case BLK_MQ:
+ if (softirq_enable) {
+ blk_mq_complete_request(rq);
+ } else {
+ ibnbd_put_tag(dev->sess, iu->tag);
+ blk_mq_end_request(rq, iu->status);
+ }
+ break;
+ case BLK_RQ:
+ if (softirq_enable)
+ blk_complete_request(rq);
+ else
+ blk_end_request_all(rq, iu->status);
+ break;
+ default:
+ WARN(true, "dev->queue_mode , contains unexpected"
+ " value: %d. Memory Corruption? Inflight I/O stalled!\n",
+ dev->queue_mode);
+ return;
+ }
+
+ 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);
+
+ 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_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));
+
+ 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_VER_MAJOR;
+
+ ibnbd_clt_get_sess(sess);
+ 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);
+ 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)
+{
+ 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 (IS_ERR(sess) || sess)
+ /* Either success or error path */
+ 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 (IS_ERR(found) || found) {
+ /* Either success or error path */
+ 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;
+ 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));
+
+ 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 (WARN_ON(dev->queue_mode != BLK_MQ))
+ return;
+ blk_mq_stop_hw_queue(hctx);
+
+ if (delay != IBNBD_DELAY_IFBUSY)
+ blk_mq_delay_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_queue(hctx, IBNBD_DELAY_10ms);
+}
+
+static void ibnbd_clt_dev_kick_queue(struct ibnbd_clt_dev *dev, int delay)
+{
+ if (WARN_ON(dev->queue_mode != BLK_RQ))
+ return;
+ blk_stop_queue(dev->queue);
+
+ if (delay != IBNBD_DELAY_IFBUSY)
+ ibnbd_blk_delay_queue(dev, delay);
+ else if (unlikely(!ibnbd_clt_dev_add_to_requeue(dev, dev->hw_queues)))
+ /* If session is not busy we have to restart
+ * the queue ourselves.
+ */
+ ibnbd_blk_delay_queue(dev, 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 ibnbd_rq_prep_fn(struct request_queue *q, struct request *rq)
+{
+ struct ibnbd_clt_dev *dev = q->queuedata;
+ struct ibnbd_iu *iu;
+
+ iu = ibnbd_get_iu(dev->sess, IBTRS_TAG_NOWAIT, IBTRS_IO_CON);
+ if (likely(iu)) {
+ rq->special = iu;
+ rq->rq_flags |= RQF_DONTPREP;
+
+ return BLKPREP_OK;
+ }
+
+ ibnbd_clt_dev_kick_queue(dev, IBNBD_DELAY_IFBUSY);
+ return BLKPREP_DEFER;
+}
+
+static void ibnbd_rq_unprep_fn(struct request_queue *q, struct request *rq)
+{
+ struct ibnbd_clt_dev *dev = q->queuedata;
+
+ if (WARN_ON(!rq->special))
+ return;
+ ibnbd_put_iu(dev->sess, rq->special);
+ rq->special = NULL;
+ rq->rq_flags &= ~RQF_DONTPREP;
+}
+
+static void ibnbd_clt_request(struct request_queue *q)
+__must_hold(q->queue_lock)
+{
+ int err;
+ struct request *req;
+ struct ibnbd_iu *iu;
+ struct ibnbd_clt_dev *dev = q->queuedata;
+
+ while ((req = blk_fetch_request(q)) != NULL) {
+ spin_unlock_irq(q->queue_lock);
+
+ if (unlikely(!ibnbd_clt_dev_is_mapped(dev))) {
+ err = -EIO;
+ goto next;
+ }
+
+ iu = req->special;
+ if (WARN_ON(!iu)) {
+ err = -EIO;
+ goto next;
+ }
+
+ sg_init_table(iu->sglist, dev->max_segments);
+ err = ibnbd_client_xfer_request(dev, req, iu);
+next:
+ if (unlikely(err == -EAGAIN || err == -ENOMEM)) {
+ ibnbd_rq_unprep_fn(q, req);
+ spin_lock_irq(q->queue_lock);
+ blk_requeue_request(q, req);
+ ibnbd_clt_dev_kick_queue(dev, IBNBD_DELAY_10ms);
+ break;
+ } else if (err) {
+ blk_end_request_all(req, err);
+ }
+
+ spin_lock_irq(q->queue_lock);
+ }
+}
+
+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 int setup_rq_dev(struct ibnbd_clt_dev *dev)
+{
+ dev->queue = blk_init_queue(ibnbd_clt_request, NULL);
+ if (IS_ERR_OR_NULL(dev->queue)) {
+ if (IS_ERR(dev->queue)) {
+ ibnbd_err(dev, "Initializing request queue failed, "
+ "err: %ld\n", PTR_ERR(dev->queue));
+ return PTR_ERR(dev->queue);
+ }
+ ibnbd_err(dev, "Initializing request queue failed\n");
+ return -ENOMEM;
+ }
+
+ blk_queue_prep_rq(dev->queue, ibnbd_rq_prep_fn);
+ blk_queue_softirq_done(dev->queue, ibnbd_softirq_done_fn);
+ blk_queue_unprep_rq(dev->queue, ibnbd_rq_unprep_fn);
+
+ 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);
+
+ 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)
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, dev->queue);
+ if (dev->secure_discard)
+ queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, dev->queue);
+
+ queue_flag_set_unlocked(QUEUE_FLAG_SAME_COMP, dev->queue);
+ queue_flag_set_unlocked(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_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, queue_mode=%s\n",
+ dev->gd->disk_name,
+ dev->nsectors * (dev->logical_block_size / KERNEL_SECTOR_SIZE),
+ ibnbd_queue_mode_str(dev->queue_mode));
+
+ 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)
+ queue_flag_set_unlocked(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;
+
+ switch (dev->queue_mode) {
+ case BLK_MQ:
+ err = setup_mq_dev(dev);
+ break;
+ case BLK_RQ:
+ err = setup_rq_dev(dev);
+ break;
+ default:
+ err = -EINVAL;
+ }
+
+ 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_queue_mode queue_mode,
+ enum ibnbd_io_mode io_mode,
+ const char *pathname)
+{
+ int ret;
+ struct ibnbd_clt_dev *dev;
+ size_t nr;
+
+ dev = kzalloc_node(sizeof(*dev), GFP_KERNEL, NUMA_NO_NODE);
+ if (!dev)
+ return ERR_PTR(-ENOMEM);
+
+ nr = (queue_mode == BLK_MQ ? nr_cpu_ids : 1);
+ dev->hw_queues = kcalloc(nr, 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;
+ }
+ if (queue_mode == BLK_RQ)
+ ibnbd_init_hw_queue(dev, dev->hw_queues, NULL);
+ 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->queue_mode = queue_mode;
+ dev->io_mode = io_mode;
+ strlcpy(dev->pathname, pathname, sizeof(dev->pathname));
+ INIT_DELAYED_WORK(&dev->rq_delay_work, ibnbd_blk_delay_work);
+ 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.
+ */
+ 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_queue_mode queue_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, queue_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 */
+ ibnbd_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;
+ enum ibnbd_clt_dev_state prev_state;
+ int refcount, ret = 0;
+
+ 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;
+ }
+ prev_state = dev->dev_state;
+ dev->dev_state = DEV_STATE_UNMAPPED;
+ mutex_unlock(&dev->lock);
+
+ delete_dev(dev);
+
+ if (prev_state == DEV_STATE_MAPPED && sess->ibtrs)
+ send_msg_close(dev, dev->device_id, WAIT);
+
+ ibnbd_info(dev, "Device is unmapped\n");
+ destroy_sysfs(dev, sysfs_self);
+ destroy_gen_disk(dev);
+
+ /* 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) {
+ 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);
+ schedule_work(&dev->unmap_on_rmmod_work);
+ }
+ ibnbd_clt_put_sess(sess);
+ }
+ /* Wait for all scheduled unmap works */
+ flush_scheduled_work();
+ WARN_ON(!list_empty(&sess_list));
+}
+
+static int __init ibnbd_client_init(void)
+{
+ int err;
+
+ pr_info("Loading module %s, version %s: (softirq_enable: %d)\n",
+ KBUILD_MODNAME, IBNBD_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;
+ }
+
+ return 0;
+
+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);
+ pr_info("Module unloaded\n");
+}
+
+module_init(ibnbd_client_init);
+module_exit(ibnbd_client_exit);
--
2.13.1