[PATCH 4/6] iser RDMA CM (CMA) and IB verbs interaction

From: Or Gerlitz
Date: Wed May 10 2006 - 09:21:54 EST

--- /usr/src/linux-2.6.17-rc3/drivers/infiniband/ulp/iser-x/iser_verbs.c 1970-01-01 02:00:00.000000000 +0200
+++ /usr/src/linux-2.6.17-rc3/drivers/infiniband/ulp/iser/iser_verbs.c 2006-05-10 15:32:01.000000000 +0300
@@ -0,0 +1,827 @@
+/*
+ * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
+ * Copyright (c) 2005, 2006 Cisco Systems. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses. You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * $Id: iser_verbs.c 7051 2006-05-10 12:29:11Z ogerlitz $
+ */
+#include <asm/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/smp_lock.h>
+#include <linux/delay.h>
+#include <linux/version.h>
+
+#include "iscsi_iser.h"
+
+#define ISCSI_ISER_MAX_CONN 8
+#define ISER_MAX_CQ_LEN ((ISER_QP_MAX_RECV_DTOS + \
+ ISER_QP_MAX_REQ_DTOS) * \
+ ISCSI_ISER_MAX_CONN)
+
+static void iser_cq_tasklet_fn(unsigned long data);
+static void iser_cq_callback(struct ib_cq *cq, void *cq_context);
+static void iser_comp_error_worker(void *data);
+
+static void iser_cq_event_callback(struct ib_event *cause, void *context)
+{
+ iser_err("got cq event %d \n", cause->event);
+}
+
+static void iser_qp_event_callback(struct ib_event *cause, void *context)
+{
+ iser_err("got qp event %d\n",cause->event);
+}
+
+/**
+ * iser_create_device_ib_res - creates Protection Domain (PD), Completion
+ * Queue (CQ), DMA Memory Region (DMA MR) with the device associated with
+ * the adapator.
+ *
+ * returns 0 on success, -1 on failure
+ */
+static int iser_create_device_ib_res(struct iser_device *device)
+{
+ device->pd = ib_alloc_pd(device->ib_device);
+ if (IS_ERR(device->pd))
+ goto pd_err;
+
+ device->cq = ib_create_cq(device->ib_device,
+ iser_cq_callback,
+ iser_cq_event_callback,
+ (void *)device,
+ ISER_MAX_CQ_LEN);
+ if (IS_ERR(device->cq))
+ goto cq_err;
+
+ if (ib_req_notify_cq(device->cq, IB_CQ_NEXT_COMP))
+ goto cq_arm_err;
+
+ tasklet_init(&device->cq_tasklet,
+ iser_cq_tasklet_fn,
+ (unsigned long)device);
+
+ device->mr = ib_get_dma_mr(device->pd,
+ IB_ACCESS_LOCAL_WRITE);
+ if (IS_ERR(device->mr))
+ goto dma_mr_err;
+
+ return 0;
+
+dma_mr_err:
+ tasklet_kill(&device->cq_tasklet);
+cq_arm_err:
+ ib_destroy_cq(device->cq);
+cq_err:
+ ib_dealloc_pd(device->pd);
+pd_err:
+ iser_err("failed to allocate an IB resource\n");
+ return -1;
+}
+
+/**
+ * iser_free_device_ib_res - destory/dealloc/dereg the DMA MR,
+ * CQ and PD created with the device associated with the adapator.
+ */
+static void iser_free_device_ib_res(struct iser_device *device)
+{
+ BUG_ON(device->mr == NULL);
+
+ tasklet_kill(&device->cq_tasklet);
+
+ (void)ib_dereg_mr(device->mr);
+ (void)ib_destroy_cq(device->cq);
+ (void)ib_dealloc_pd(device->pd);
+
+ device->mr = NULL;
+ device->cq = NULL;
+ device->pd = NULL;
+}
+
+/**
+ * iser_create_ib_conn_res - Creates FMR pool and Queue-Pair (QP)
+ *
+ * returns 0 on success, -1 on failure
+ */
+static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
+{
+ struct iser_device *device;
+ struct ib_qp_init_attr init_attr;
+ int ret;
+ struct ib_fmr_pool_param params;
+
+ BUG_ON(ib_conn->device == NULL);
+
+ device = ib_conn->device;
+
+ ib_conn->page_vec = kmalloc(sizeof(struct iser_page_vec) +
+ (sizeof(u64) * (ISCSI_ISER_SG_TABLESIZE +1)),
+ GFP_KERNEL);
+ if (!ib_conn->page_vec) {
+ ret = -ENOMEM;
+ goto alloc_err;
+ }
+ ib_conn->page_vec->pages = (u64 *) (ib_conn->page_vec + 1);
+
+ params.page_shift = PAGE_SHIFT;
+ /* when the first/last SG element are not start/end *
+ * page aligned, the map whould be of N+1 pages */
+ params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE + 1;
+ /* make the pool size twice the max number of SCSI commands *
+ * the ML is expected to queue, watermark for unmap at 50% */
+ params.pool_size = ISCSI_XMIT_CMDS_MAX * 2;
+ params.dirty_watermark = ISCSI_XMIT_CMDS_MAX;
+ params.cache = 0;
+ params.flush_function = NULL;
+ params.access = (IB_ACCESS_LOCAL_WRITE |
+ IB_ACCESS_REMOTE_WRITE |
+ IB_ACCESS_REMOTE_READ);
+
+ ib_conn->fmr_pool = ib_create_fmr_pool(device->pd, &params);
+ if (IS_ERR(ib_conn->fmr_pool)) {
+ ret = PTR_ERR(ib_conn->fmr_pool);
+ goto fmr_pool_err;
+ }
+
+ memset(&init_attr, 0, sizeof init_attr);
+
+ init_attr.event_handler = iser_qp_event_callback;
+ init_attr.qp_context = (void *)ib_conn;
+ init_attr.send_cq = device->cq;
+ init_attr.recv_cq = device->cq;
+ init_attr.cap.max_send_wr = ISER_QP_MAX_REQ_DTOS;
+ init_attr.cap.max_recv_wr = ISER_QP_MAX_RECV_DTOS;
+ init_attr.cap.max_send_sge = MAX_REGD_BUF_VECTOR_LEN;
+ init_attr.cap.max_recv_sge = 2;
+ init_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
+ init_attr.qp_type = IB_QPT_RC;
+
+ ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);
+ if (ret)
+ goto qp_err;
+
+ ib_conn->qp = ib_conn->cma_id->qp;
+ iser_err("setting conn %p cma_id %p: fmr_pool %p qp %p\n",
+ ib_conn, ib_conn->cma_id,
+ ib_conn->fmr_pool, ib_conn->cma_id->qp);
+ return ret;
+
+qp_err:
+ (void)ib_destroy_fmr_pool(ib_conn->fmr_pool);
+fmr_pool_err:
+ kfree(ib_conn->page_vec);
+alloc_err:
+ iser_err("unable to alloc mem or create resource, err %d\n", ret);
+ return ret;
+}
+
+/**
+ * releases the FMR pool, QP and CMA ID objects, returns 0 on success,
+ * -1 on failure
+ */
+static int iser_free_ib_conn_res(struct iser_conn *ib_conn)
+{
+ BUG_ON(ib_conn == NULL);
+
+ iser_err("freeing conn %p cma_id %p fmr pool %p qp %p\n",
+ ib_conn, ib_conn->cma_id,
+ ib_conn->fmr_pool, ib_conn->qp);
+
+ /* qp is created only once both addr & route are resolved */
+ if (ib_conn->fmr_pool != NULL)
+ ib_destroy_fmr_pool(ib_conn->fmr_pool);
+
+ if (ib_conn->qp != NULL)
+ rdma_destroy_qp(ib_conn->cma_id);
+
+ if (ib_conn->cma_id != NULL)
+ rdma_destroy_id(ib_conn->cma_id);
+
+ ib_conn->fmr_pool = NULL;
+ ib_conn->qp = NULL;
+ ib_conn->cma_id = NULL;
+ kfree(ib_conn->page_vec);
+
+ return 0;
+}
+
+/**
+ * based on the resolved device node GUID see if there already allocated
+ * device for this device. If there's no such, create one.
+ */
+static
+struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
+{
+ struct list_head *p_list;
+ struct iser_device *device = NULL;
+
+ mutex_lock(&ig.device_list_mutex);
+
+ p_list = ig.device_list.next;
+ while (p_list != &ig.device_list) {
+ device = list_entry(p_list, struct iser_device, ig_list);
+ /* find if there's a match using the node GUID */
+ if (device->ib_device->node_guid == cma_id->device->node_guid)
+ break;
+ }
+
+ if (device == NULL) {
+ device = kzalloc(sizeof *device, GFP_KERNEL);
+ if (device == NULL)
+ goto out;
+ /* assign this device to the device */
+ device->ib_device = cma_id->device;
+ /* init the device and link it into ig device list */
+ if (iser_create_device_ib_res(device)) {
+ kfree(device);
+ device = NULL;
+ goto out;
+ }
+ list_add(&device->ig_list, &ig.device_list);
+ }
+out:
+ BUG_ON(device == NULL);
+ device->refcount++;
+ mutex_unlock(&ig.device_list_mutex);
+ return device;
+}
+
+/* if there's no demand for this device, release it */
+static void iser_device_try_release(struct iser_device *device)
+{
+ mutex_lock(&ig.device_list_mutex);
+ device->refcount--;
+ iser_err("device %p refcount %d\n",device,device->refcount);
+ if (!device->refcount) {
+ iser_free_device_ib_res(device);
+ list_del(&device->ig_list);
+ kfree(device);
+ }
+ mutex_unlock(&ig.device_list_mutex);
+}
+
+int iser_conn_state_comp(struct iser_conn *ib_conn,
+ enum iser_ib_conn_state comp)
+{
+ int ret;
+
+ spin_lock_bh(&ib_conn->lock);
+ ret = (ib_conn->state == comp);
+ spin_unlock_bh(&ib_conn->lock);
+ return ret;
+}
+
+static int iser_conn_state_comp_exch(struct iser_conn *ib_conn,
+ enum iser_ib_conn_state comp,
+ enum iser_ib_conn_state exch)
+{
+ int ret;
+
+ spin_lock_bh(&ib_conn->lock);
+ if ((ret = (ib_conn->state == comp)))
+ ib_conn->state = exch;
+ spin_unlock_bh(&ib_conn->lock);
+ return ret;
+}
+
+/**
+ * triggers start of the disconnect procedures and wait for them to be done
+ */
+void iser_conn_terminate(struct iser_conn *ib_conn)
+{
+ int err = 0;
+
+ /* change the ib conn state only if the conn is UP, however always call
+ * rdma_disconnect since this is the only way to cause the CMA to change
+ * the QP state to ERROR
+ */
+
+ iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP, ISER_CONN_TERMINATING);
+ err = rdma_disconnect(ib_conn->cma_id);
+ if (err)
+ iser_err("Failed to disconnect, conn: 0x%p err %d\n",
+ ib_conn,err);
+
+ wait_event_interruptible(ib_conn->wait,
+ ib_conn->state == ISER_CONN_DOWN);
+
+ iser_conn_release(ib_conn);
+}
+
+static void iser_connect_error(struct rdma_cm_id *cma_id)
+{
+ struct iser_conn *ib_conn;
+ ib_conn = (struct iser_conn *)cma_id->context;
+
+ ib_conn->state = ISER_CONN_DOWN;
+ wake_up_interruptible(&ib_conn->wait);
+}
+
+static void iser_addr_handler(struct rdma_cm_id *cma_id)
+{
+ struct iser_device *device;
+ struct iser_conn *ib_conn;
+ int ret;
+
+ device = iser_device_find_by_ib_device(cma_id);
+ ib_conn = (struct iser_conn *)cma_id->context;
+ ib_conn->device = device;
+
+ ret = rdma_resolve_route(cma_id, 1000);
+ if (ret) {
+ iser_err("resolve route failed: %d\n", ret);
+ iser_connect_error(cma_id);
+ }
+ return;
+}
+
+static void iser_route_handler(struct rdma_cm_id *cma_id)
+{
+ struct rdma_conn_param conn_param;
+ int ret;
+
+ ret = iser_create_ib_conn_res((struct iser_conn *)cma_id->context);
+ if (ret)
+ goto failure;
+
+ iser_dbg("path.mtu is %d setting it to %d\n",
+ cma_id->route.path_rec->mtu, IB_MTU_1024);
+
+ /* we must set the MTU to 1024 as this is what the target is assuming */
+ if (cma_id->route.path_rec->mtu > IB_MTU_1024)
+ cma_id->route.path_rec->mtu = IB_MTU_1024;
+
+ memset(&conn_param, 0, sizeof conn_param);
+ conn_param.responder_resources = 4;
+ conn_param.initiator_depth = 1;
+ conn_param.retry_count = 7;
+ conn_param.rnr_retry_count = 6;
+
+ ret = rdma_connect(cma_id, &conn_param);
+ if (ret) {
+ iser_err("failure connecting: %d\n", ret);
+ goto failure;
+ }
+
+ return;
+failure:
+ iser_connect_error(cma_id);
+}
+
+static void iser_connected_handler(struct rdma_cm_id *cma_id)
+{
+ struct iser_conn *ib_conn;
+
+ ib_conn = (struct iser_conn *)cma_id->context;
+ ib_conn->state = ISER_CONN_UP;
+ wake_up_interruptible(&ib_conn->wait);
+}
+
+static void iser_disconnected_handler(struct rdma_cm_id *cma_id)
+{
+ struct iser_conn *ib_conn;
+
+ ib_conn = (struct iser_conn *)cma_id->context;
+ ib_conn->disc_evt_flag = 1;
+
+ /* getting here when the state is UP means that the conn is being *
+ * terminated asynchronously from the iSCSI layer's perspective. */
+ if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
+ ISER_CONN_TERMINATING))
+ iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
+ ISCSI_ERR_CONN_FAILED);
+
+ /* Complete the termination process if no posts are pending */
+ if ((atomic_read(&ib_conn->post_recv_buf_count) == 0) &&
+ (atomic_read(&ib_conn->post_send_buf_count) == 0)) {
+ ib_conn->state = ISER_CONN_DOWN;
+ wake_up_interruptible(&ib_conn->wait);
+ }
+}
+
+static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
+{
+ int ret = 0;
+
+ iser_err("event %d conn %p id %p\n",event->event,cma_id->context,cma_id);
+
+ switch (event->event) {
+ case RDMA_CM_EVENT_ADDR_RESOLVED:
+ iser_addr_handler(cma_id);
+ break;
+ case RDMA_CM_EVENT_ROUTE_RESOLVED:
+ iser_route_handler(cma_id);
+ break;
+ case RDMA_CM_EVENT_ESTABLISHED:
+ iser_connected_handler(cma_id);
+ break;
+ case RDMA_CM_EVENT_ADDR_ERROR:
+ case RDMA_CM_EVENT_ROUTE_ERROR:
+ case RDMA_CM_EVENT_CONNECT_ERROR:
+ case RDMA_CM_EVENT_UNREACHABLE:
+ case RDMA_CM_EVENT_REJECTED:
+ iser_err("event: %d, error: %d\n", event->event, event->status);
+ iser_connect_error(cma_id);
+ break;
+ case RDMA_CM_EVENT_DISCONNECTED:
+ iser_disconnected_handler(cma_id);
+ break;
+ case RDMA_CM_EVENT_DEVICE_REMOVAL:
+ BUG();
+ break;
+ case RDMA_CM_EVENT_CONNECT_RESPONSE:
+ BUG();
+ break;
+ case RDMA_CM_EVENT_CONNECT_REQUEST:
+ default:
+ break;
+ }
+ return ret;
+}
+
+int iser_conn_init(struct iser_conn **ibconn)
+{
+ struct iser_conn *ib_conn;
+
+ ib_conn = kzalloc(sizeof *ib_conn, GFP_KERNEL);
+ if (!ib_conn) {
+ iser_err("can't alloc memory for struct iser_conn\n");
+ return -ENOMEM;
+ }
+ ib_conn->state = ISER_CONN_INIT;
+ init_waitqueue_head(&ib_conn->wait);
+ atomic_set(&ib_conn->post_recv_buf_count, 0);
+ atomic_set(&ib_conn->post_send_buf_count, 0);
+ INIT_WORK(&ib_conn->comperror_work, iser_comp_error_worker,
+ ib_conn);
+ INIT_LIST_HEAD(&ib_conn->conn_list);
+ spin_lock_init(&ib_conn->lock);
+
+ *ibconn = ib_conn;
+ return 0;
+}
+
+ /**
+ * starts the process of connecting to the target
+ * sleeps untill the connection is established or rejected
+ */
+int iser_connect(struct iser_conn *ib_conn,
+ struct sockaddr_in *src_addr,
+ struct sockaddr_in *dst_addr,
+ int non_blocking)
+{
+ struct sockaddr *src, *dst;
+ int err = 0;
+
+ sprintf(ib_conn->name,"%d.%d.%d.%d:%d",
+ NIPQUAD(dst_addr->sin_addr.s_addr), dst_addr->sin_port);
+
+ /* the device is known only --after-- address resolution */
+ ib_conn->device = NULL;
+
+ iser_err("connecting to: %d.%d.%d.%d, port 0x%x\n",
+ NIPQUAD(dst_addr->sin_addr), dst_addr->sin_port);
+
+ ib_conn->state = ISER_CONN_PENDING;
+
+ ib_conn->cma_id = rdma_create_id(iser_cma_handler,
+ (void *)ib_conn,
+ RDMA_PS_TCP);
+ if (IS_ERR(ib_conn->cma_id)) {
+ err = PTR_ERR(ib_conn->cma_id);
+ iser_err("rdma_create_id failed: %d\n", err);
+ goto id_failure;
+ }
+
+ src = (struct sockaddr *)src_addr;
+ dst = (struct sockaddr *)dst_addr;
+ err = rdma_resolve_addr(ib_conn->cma_id, src, dst, 1000);
+ if (err) {
+ iser_err("rdma_resolve_addr failed: %d\n", err);
+ goto addr_failure;
+ }
+
+ if (!non_blocking) {
+ wait_event_interruptible(ib_conn->wait,
+ (ib_conn->state != ISER_CONN_PENDING));
+
+ if (ib_conn->state != ISER_CONN_UP) {
+ err = -EIO;
+ goto connect_failure;
+ }
+ }
+
+ mutex_lock(&ig.connlist_mutex);
+ list_add(&ib_conn->conn_list, &ig.connlist);
+ mutex_unlock(&ig.connlist_mutex);
+ return 0;
+
+id_failure:
+ ib_conn->cma_id = NULL;
+addr_failure:
+ ib_conn->state = ISER_CONN_DOWN;
+connect_failure:
+ iser_conn_release(ib_conn);
+ return err;
+}
+
+/**
+ * Frees all conn objects and deallocs conn descriptor
+ */
+void iser_conn_release(struct iser_conn *ib_conn)
+{
+ struct iser_device *device = ib_conn->device;
+
+ BUG_ON(ib_conn->state != ISER_CONN_DOWN);
+
+ mutex_lock(&ig.connlist_mutex);
+ list_del(&ib_conn->conn_list);
+ mutex_unlock(&ig.connlist_mutex);
+
+ iser_free_ib_conn_res(ib_conn);
+ ib_conn->device = NULL;
+ /* on EVENT_ADDR_ERROR there's no device yet for this conn */
+ if (device != NULL)
+ iser_device_try_release(device);
+ kfree(ib_conn);
+}
+
+
+/**
+ * iser_reg_page_vec - Register physical memory
+ *
+ * returns: 0 on success, errno code on failure
+ */
+int iser_reg_page_vec(struct iser_conn *ib_conn,
+ struct iser_page_vec *page_vec,
+ struct iser_mem_reg *mem_reg)
+{
+ struct ib_pool_fmr *mem;
+ u64 io_addr;
+ u64 *page_list;
+ int status;
+
+ page_list = page_vec->pages;
+ io_addr = page_list[0];
+
+ mem = ib_fmr_pool_map_phys(ib_conn->fmr_pool,
+ page_list,
+ page_vec->length,
+ &io_addr);
+
+ if (IS_ERR(mem)) {
+ status = (int)PTR_ERR(mem);
+ iser_err("ib_fmr_pool_map_phys failed: %d\n", status);
+ return status;
+ }
+
+ mem_reg->lkey = mem->fmr->lkey;
+ mem_reg->rkey = mem->fmr->rkey;
+ mem_reg->len = page_vec->length * PAGE_SIZE;
+ mem_reg->va = io_addr;
+ mem_reg->mem_h = (void *)mem;
+
+ mem_reg->va += page_vec->offset;
+ mem_reg->len = page_vec->data_size;
+
+ iser_dbg("PHYSICAL Mem.register, [PHYS p_array: 0x%p, sz: %d, "
+ "entry[0]: (0x%08lx,%ld)] -> "
+ "[lkey: 0x%08X mem_h: 0x%p va: 0x%08lX sz: %ld]\n",
+ page_vec, page_vec->length,
+ (unsigned long)page_vec->pages[0],
+ (unsigned long)page_vec->data_size,
+ (unsigned int)mem_reg->lkey, mem_reg->mem_h,
+ (unsigned long)mem_reg->va, (unsigned long)mem_reg->len);
+ return 0;
+}
+
+/**
+ * Unregister (previosuly registered) memory.
+ */
+void iser_unreg_mem(struct iser_mem_reg *reg)
+{
+ int ret;
+
+ iser_dbg("PHYSICAL Mem.Unregister mem_h %p\n",reg->mem_h);
+
+ ret = ib_fmr_pool_unmap((struct ib_pool_fmr *)reg->mem_h);
+ if (ret)
+ iser_err("ib_fmr_pool_unmap failed %d\n", ret);
+
+ reg->mem_h = NULL;
+}
+
+/**
+ * iser_dto_to_iov - builds IOV from a dto descriptor
+ */
+static void iser_dto_to_iov(struct iser_dto *dto, struct ib_sge *iov, int iov_len)
+{
+ int i;
+ struct ib_sge *sge;
+ struct iser_regd_buf *regd_buf;
+
+ if (dto->regd_vector_len > iov_len) {
+ iser_err("iov size %d too small for posting dto of len %d\n",
+ iov_len, dto->regd_vector_len);
+ BUG();
+ }
+
+ for (i = 0; i < dto->regd_vector_len; i++) {
+ sge = &iov[i];
+ regd_buf = dto->regd[i];
+
+ sge->addr = regd_buf->reg.va;
+ sge->length = regd_buf->reg.len;
+ sge->lkey = regd_buf->reg.lkey;
+
+ if (dto->used_sz[i] > 0) /* Adjust size */
+ sge->length = dto->used_sz[i];
+
+ /* offset and length should not exceed the regd buf length */
+ if (sge->length + dto->offset[i] > regd_buf->reg.len) {
+ iser_err("Used len:%ld + offset:%d, exceed reg.buf.len:"
+ "%ld in dto:0x%p [%d], va:0x%08lX\n",
+ (unsigned long)sge->length, dto->offset[i],
+ (unsigned long)regd_buf->reg.len, dto, i,
+ (unsigned long)sge->addr);
+ BUG();
+ }
+
+ sge->addr += dto->offset[i]; /* Adjust offset */
+ }
+}
+
+/**
+ * iser_post_recv - Posts a receive buffer.
+ *
+ * returns 0 on success, -1 on failure
+ */
+int iser_post_recv(struct iser_desc *rx_desc)
+{
+ int ib_ret, ret_val = 0;
+ struct ib_recv_wr recv_wr, *recv_wr_failed;
+ struct ib_sge iov[2];
+ struct iser_conn *ib_conn;
+ struct iser_dto *recv_dto = &rx_desc->dto;
+
+ /* Retrieve conn */
+ ib_conn = recv_dto->conn->ib_conn;
+
+ iser_dto_to_iov(recv_dto, iov, 2);
+
+ recv_wr.next = NULL;
+ recv_wr.sg_list = iov;
+ recv_wr.num_sge = recv_dto->regd_vector_len;
+ recv_wr.wr_id = (unsigned long)rx_desc;
+
+ atomic_inc(&ib_conn->post_recv_buf_count);
+ ib_ret = ib_post_recv(ib_conn->qp, &recv_wr, &recv_wr_failed);
+ if (ib_ret) {
+ iser_err("ib_post_recv failed ret=%d\n", ib_ret);
+ atomic_dec(&ib_conn->post_recv_buf_count);
+ ret_val = -1;
+ }
+
+ return ret_val;
+}
+
+/**
+ * iser_start_send - Initiate a Send DTO operation
+ *
+ * returns 0 on success, -1 on failure
+ */
+int iser_post_send(struct iser_desc *tx_desc)
+{
+ int ib_ret, ret_val = 0;
+ struct ib_send_wr send_wr, *send_wr_failed;
+ struct ib_sge iov[MAX_REGD_BUF_VECTOR_LEN];
+ struct iser_conn *ib_conn;
+ struct iser_dto *dto = &tx_desc->dto;
+
+ ib_conn = dto->conn->ib_conn;
+
+ iser_dto_to_iov(dto, iov, MAX_REGD_BUF_VECTOR_LEN);
+
+ send_wr.next = NULL;
+ send_wr.wr_id = (unsigned long)tx_desc;
+ send_wr.sg_list = iov;
+ send_wr.num_sge = dto->regd_vector_len;
+ send_wr.opcode = IB_WR_SEND;
+ send_wr.send_flags = dto->notify_enable ? IB_SEND_SIGNALED : 0;
+
+ atomic_inc(&ib_conn->post_send_buf_count);
+
+ ib_ret = ib_post_send(ib_conn->qp, &send_wr, &send_wr_failed);
+ if (ib_ret) {
+ iser_err("Failed to start SEND DTO, dto: 0x%p, IOV len: %d\n",
+ dto, dto->regd_vector_len);
+ iser_err("ib_post_send failed, ret:%d\n", ib_ret);
+ atomic_dec(&ib_conn->post_send_buf_count);
+ ret_val = -1;
+ }
+
+ return ret_val;
+}
+
+static void iser_comp_error_worker(void *data)
+{
+ struct iser_conn *ib_conn = data;
+
+ /* getting here when the state is UP means that the conn is being *
+ * terminated asynchronously from the iSCSI layer's perspective. */
+ if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
+ ISER_CONN_TERMINATING))
+ iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
+ ISCSI_ERR_CONN_FAILED);
+
+ /* complete the termination process if disconnect event was delivered *
+ * note there are no more non completed posts to the QP */
+ if (ib_conn->disc_evt_flag) {
+ ib_conn->state = ISER_CONN_DOWN;
+ wake_up_interruptible(&ib_conn->wait);
+ }
+}
+
+static void iser_handle_comp_error(struct iser_desc *desc)
+{
+ struct iser_dto *dto = &desc->dto;
+ struct iser_conn *ib_conn = dto->conn->ib_conn;
+
+ iser_dto_buffs_release(dto);
+
+ if (desc->type == ISCSI_RX) {
+ kfree(desc->data);
+ kmem_cache_free(ig.desc_cache, desc);
+ atomic_dec(&ib_conn->post_recv_buf_count);
+ } else { /* type is TX control/command/dataout */
+ if (desc->type == ISCSI_TX_DATAOUT)
+ kmem_cache_free(ig.desc_cache, desc);
+ atomic_dec(&ib_conn->post_send_buf_count);
+ }
+
+ if (atomic_read(&ib_conn->post_recv_buf_count) == 0 &&
+ atomic_read(&ib_conn->post_send_buf_count) == 0)
+ schedule_work(&ib_conn->comperror_work);
+}
+
+static void iser_cq_tasklet_fn(unsigned long data)
+{
+ struct iser_device *device = (struct iser_device *)data;
+ struct ib_cq *cq = device->cq;
+ struct ib_wc wc;
+ struct iser_desc *desc;
+ unsigned long xfer_len;
+
+ while (ib_poll_cq(cq, 1, &wc) == 1) {
+ desc = (struct iser_desc *) (unsigned long) wc.wr_id;
+ BUG_ON(desc == NULL);
+
+ if (wc.status == IB_WC_SUCCESS) {
+ if (desc->type == ISCSI_RX) {
+ xfer_len = (unsigned long)wc.byte_len;
+ iser_rcv_completion(desc, xfer_len);
+ } else /* type == ISCSI_TX_CONTROL/SCSI_CMD/DOUT */
+ iser_snd_completion(desc);
+ } else {
+ iser_err("comp w. error op %d status %d\n",desc->type,wc.status);
+ iser_handle_comp_error(desc);
+ }
+ }
+ /* #warning "it is assumed here that arming CQ only once its empty" *
+ * " would not cause interrupts to be missed" */
+ ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
+}
+
+static void iser_cq_callback(struct ib_cq *cq, void *cq_context)
+{
+ struct iser_device *device = (struct iser_device *)cq_context;
+
+ tasklet_schedule(&device->cq_tasklet);
+}

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