IB/iser: Introduce fast memory registration model (FRWR)
Newer HCAs and Virtual functions may not support FMRs but rather a fast
registration model, which we call FRWR - "Fast Registration Work Requests".
This model was introduced in 00f7ec36c ("RDMA/core: Add memory management
extensions support") and works when the IB device supports the
IB_DEVICE_MEM_MGT_EXTENSIONS capability.
Upon creating the iser device iser will test whether the HCA supports
FMRs. If no support for FMRs, check if IB_DEVICE_MEM_MGT_EXTENSIONS
is supported and assign function pointers that handle fast
registration and allocation of appropriate resources (fast_reg
descriptors).
Registration is done using posting IB_WR_FAST_REG_MR to the QP and
invalidations using posting IB_WR_LOCAL_INV.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.h b/drivers/infiniband/ulp/iser/iscsi_iser.h
index 75c5352..6791402 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.h
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.h
@@ -211,7 +211,7 @@
u64 va;
u64 len;
void *mem_h;
- int is_fmr;
+ int is_mr;
};
struct iser_regd_buf {
@@ -277,6 +277,15 @@
enum iser_data_dir cmd_dir);
};
+struct fast_reg_descriptor {
+ struct list_head list;
+ /* For fast registration - FRWR */
+ struct ib_mr *data_mr;
+ struct ib_fast_reg_page_list *data_frpl;
+ /* Valid for fast registration flag */
+ bool valid;
+};
+
struct iser_conn {
struct iscsi_iser_conn *iser_conn; /* iser conn for upcalls */
struct iscsi_endpoint *ep;
@@ -307,6 +316,10 @@
struct iser_page_vec *page_vec; /* represents SG to fmr maps*
* maps serialized as tx is*/
} fmr;
+ struct {
+ struct list_head pool;
+ int pool_size;
+ } frwr;
} fastreg;
};
@@ -393,6 +406,8 @@
int iser_reg_rdma_mem_fmr(struct iscsi_iser_task *task,
enum iser_data_dir cmd_dir);
+int iser_reg_rdma_mem_frwr(struct iscsi_iser_task *task,
+ enum iser_data_dir cmd_dir);
int iser_connect(struct iser_conn *ib_conn,
struct sockaddr_in *src_addr,
@@ -405,6 +420,8 @@
void iser_unreg_mem_fmr(struct iscsi_iser_task *iser_task,
enum iser_data_dir cmd_dir);
+void iser_unreg_mem_frwr(struct iscsi_iser_task *iser_task,
+ enum iser_data_dir cmd_dir);
int iser_post_recvl(struct iser_conn *ib_conn);
int iser_post_recvm(struct iser_conn *ib_conn, int count);
@@ -421,4 +438,6 @@
int iser_alloc_rx_descriptors(struct iser_conn *ib_conn, struct iscsi_session *session);
int iser_create_fmr_pool(struct iser_conn *ib_conn, unsigned cmds_max);
void iser_free_fmr_pool(struct iser_conn *ib_conn);
+int iser_create_frwr_pool(struct iser_conn *ib_conn, unsigned cmds_max);
+void iser_free_frwr_pool(struct iser_conn *ib_conn);
#endif
diff --git a/drivers/infiniband/ulp/iser/iser_memory.c b/drivers/infiniband/ulp/iser/iser_memory.c
index 1985e90..1ce0c97 100644
--- a/drivers/infiniband/ulp/iser/iser_memory.c
+++ b/drivers/infiniband/ulp/iser/iser_memory.c
@@ -395,8 +395,7 @@
regd_buf = &iser_task->rdma_regd[cmd_dir];
aligned_len = iser_data_buf_aligned_len(mem, ibdev);
- if (aligned_len != mem->dma_nents ||
- (!ib_conn->fastreg.fmr.pool && mem->dma_nents > 1)) {
+ if (aligned_len != mem->dma_nents) {
err = fall_to_bounce_buf(iser_task, ibdev,
cmd_dir, aligned_len);
if (err) {
@@ -414,7 +413,7 @@
regd_buf->reg.rkey = device->mr->rkey;
regd_buf->reg.len = ib_sg_dma_len(ibdev, &sg[0]);
regd_buf->reg.va = ib_sg_dma_address(ibdev, &sg[0]);
- regd_buf->reg.is_fmr = 0;
+ regd_buf->reg.is_mr = 0;
iser_dbg("PHYSICAL Mem.register: lkey: 0x%08X rkey: 0x%08X "
"va: 0x%08lX sz: %ld]\n",
@@ -444,3 +443,138 @@
}
return 0;
}
+
+static int iser_fast_reg_mr(struct fast_reg_descriptor *desc,
+ struct iser_conn *ib_conn,
+ struct iser_regd_buf *regd_buf,
+ u32 offset, unsigned int data_size,
+ unsigned int page_list_len)
+{
+ struct ib_send_wr fastreg_wr, inv_wr;
+ struct ib_send_wr *bad_wr, *wr = NULL;
+ u8 key;
+ int ret;
+
+ if (!desc->valid) {
+ memset(&inv_wr, 0, sizeof(inv_wr));
+ inv_wr.opcode = IB_WR_LOCAL_INV;
+ inv_wr.send_flags = IB_SEND_SIGNALED;
+ inv_wr.ex.invalidate_rkey = desc->data_mr->rkey;
+ wr = &inv_wr;
+ /* Bump the key */
+ key = (u8)(desc->data_mr->rkey & 0x000000FF);
+ ib_update_fast_reg_key(desc->data_mr, ++key);
+ }
+
+ /* Prepare FASTREG WR */
+ memset(&fastreg_wr, 0, sizeof(fastreg_wr));
+ fastreg_wr.opcode = IB_WR_FAST_REG_MR;
+ fastreg_wr.send_flags = IB_SEND_SIGNALED;
+ fastreg_wr.wr.fast_reg.iova_start = desc->data_frpl->page_list[0] + offset;
+ fastreg_wr.wr.fast_reg.page_list = desc->data_frpl;
+ fastreg_wr.wr.fast_reg.page_list_len = page_list_len;
+ fastreg_wr.wr.fast_reg.page_shift = SHIFT_4K;
+ fastreg_wr.wr.fast_reg.length = data_size;
+ fastreg_wr.wr.fast_reg.rkey = desc->data_mr->rkey;
+ fastreg_wr.wr.fast_reg.access_flags = (IB_ACCESS_LOCAL_WRITE |
+ IB_ACCESS_REMOTE_WRITE |
+ IB_ACCESS_REMOTE_READ);
+
+ if (!wr) {
+ wr = &fastreg_wr;
+ atomic_inc(&ib_conn->post_send_buf_count);
+ } else {
+ wr->next = &fastreg_wr;
+ atomic_add(2, &ib_conn->post_send_buf_count);
+ }
+
+ ret = ib_post_send(ib_conn->qp, wr, &bad_wr);
+ if (ret) {
+ if (bad_wr->next)
+ atomic_sub(2, &ib_conn->post_send_buf_count);
+ else
+ atomic_dec(&ib_conn->post_send_buf_count);
+ iser_err("fast registration failed, ret:%d\n", ret);
+ return ret;
+ }
+ desc->valid = false;
+
+ regd_buf->reg.mem_h = desc;
+ regd_buf->reg.lkey = desc->data_mr->lkey;
+ regd_buf->reg.rkey = desc->data_mr->rkey;
+ regd_buf->reg.va = desc->data_frpl->page_list[0] + offset;
+ regd_buf->reg.len = data_size;
+ regd_buf->reg.is_mr = 1;
+
+ return ret;
+}
+
+/**
+ * iser_reg_rdma_mem_frwr - Registers memory intended for RDMA,
+ * using Fast Registration WR (if possible) obtaining rkey and va
+ *
+ * returns 0 on success, errno code on failure
+ */
+int iser_reg_rdma_mem_frwr(struct iscsi_iser_task *iser_task,
+ enum iser_data_dir cmd_dir)
+{
+ struct iser_conn *ib_conn = iser_task->iser_conn->ib_conn;
+ struct iser_device *device = ib_conn->device;
+ struct ib_device *ibdev = device->ib_device;
+ struct iser_data_buf *mem = &iser_task->data[cmd_dir];
+ struct iser_regd_buf *regd_buf = &iser_task->rdma_regd[cmd_dir];
+ struct fast_reg_descriptor *desc;
+ unsigned int data_size, page_list_len;
+ int err, aligned_len;
+ unsigned long flags;
+ u32 offset;
+
+ aligned_len = iser_data_buf_aligned_len(mem, ibdev);
+ if (aligned_len != mem->dma_nents) {
+ err = fall_to_bounce_buf(iser_task, ibdev,
+ cmd_dir, aligned_len);
+ if (err) {
+ iser_err("failed to allocate bounce buffer\n");
+ return err;
+ }
+ mem = &iser_task->data_copy[cmd_dir];
+ }
+
+ /* if there a single dma entry, dma mr suffices */
+ if (mem->dma_nents == 1) {
+ struct scatterlist *sg = (struct scatterlist *)mem->buf;
+
+ regd_buf->reg.lkey = device->mr->lkey;
+ regd_buf->reg.rkey = device->mr->rkey;
+ regd_buf->reg.len = ib_sg_dma_len(ibdev, &sg[0]);
+ regd_buf->reg.va = ib_sg_dma_address(ibdev, &sg[0]);
+ regd_buf->reg.is_mr = 0;
+ } else {
+ spin_lock_irqsave(&ib_conn->lock, flags);
+ desc = list_first_entry(&ib_conn->fastreg.frwr.pool,
+ struct fast_reg_descriptor, list);
+ list_del(&desc->list);
+ spin_unlock_irqrestore(&ib_conn->lock, flags);
+ page_list_len = iser_sg_to_page_vec(mem, device->ib_device,
+ desc->data_frpl->page_list,
+ &offset, &data_size);
+
+ if (page_list_len * SIZE_4K < data_size) {
+ iser_err("fast reg page_list too short to hold this SG\n");
+ err = -EINVAL;
+ goto err_reg;
+ }
+
+ err = iser_fast_reg_mr(desc, ib_conn, regd_buf,
+ offset, data_size, page_list_len);
+ if (err)
+ goto err_reg;
+ }
+
+ return 0;
+err_reg:
+ spin_lock_irqsave(&ib_conn->lock, flags);
+ list_add_tail(&desc->list, &ib_conn->fastreg.frwr.pool);
+ spin_unlock_irqrestore(&ib_conn->lock, flags);
+ return err;
+}
diff --git a/drivers/infiniband/ulp/iser/iser_verbs.c b/drivers/infiniband/ulp/iser/iser_verbs.c
index d9a47b9..28badac 100644
--- a/drivers/infiniband/ulp/iser/iser_verbs.c
+++ b/drivers/infiniband/ulp/iser/iser_verbs.c
@@ -73,12 +73,36 @@
{
int i, j;
struct iser_cq_desc *cq_desc;
+ struct ib_device_attr *dev_attr;
- /* Assign function handles */
- device->iser_alloc_rdma_reg_res = iser_create_fmr_pool;
- device->iser_free_rdma_reg_res = iser_free_fmr_pool;
- device->iser_reg_rdma_mem = iser_reg_rdma_mem_fmr;
- device->iser_unreg_rdma_mem = iser_unreg_mem_fmr;
+ dev_attr = kmalloc(sizeof(*dev_attr), GFP_KERNEL);
+ if (!dev_attr)
+ return -ENOMEM;
+
+ if (ib_query_device(device->ib_device, dev_attr)) {
+ pr_warn("Query device failed for %s\n", device->ib_device->name);
+ goto dev_attr_err;
+ }
+
+ /* Assign function handles - based on FMR support */
+ if (device->ib_device->alloc_fmr && device->ib_device->dealloc_fmr &&
+ device->ib_device->map_phys_fmr && device->ib_device->unmap_fmr) {
+ iser_info("FMR supported, using FMR for registration\n");
+ device->iser_alloc_rdma_reg_res = iser_create_fmr_pool;
+ device->iser_free_rdma_reg_res = iser_free_fmr_pool;
+ device->iser_reg_rdma_mem = iser_reg_rdma_mem_fmr;
+ device->iser_unreg_rdma_mem = iser_unreg_mem_fmr;
+ } else
+ if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
+ iser_info("FRWR supported, using FRWR for registration\n");
+ device->iser_alloc_rdma_reg_res = iser_create_frwr_pool;
+ device->iser_free_rdma_reg_res = iser_free_frwr_pool;
+ device->iser_reg_rdma_mem = iser_reg_rdma_mem_frwr;
+ device->iser_unreg_rdma_mem = iser_unreg_mem_frwr;
+ } else {
+ iser_err("IB device does not support FMRs nor FRWRs, can't register memory\n");
+ goto dev_attr_err;
+ }
device->cqs_used = min(ISER_MAX_CQ, device->ib_device->num_comp_vectors);
iser_info("using %d CQs, device %s supports %d vectors\n",
@@ -134,6 +158,7 @@
if (ib_register_event_handler(&device->event_handler))
goto handler_err;
+ kfree(dev_attr);
return 0;
handler_err:
@@ -153,6 +178,8 @@
kfree(device->cq_desc);
cq_desc_err:
iser_err("failed to allocate an IB resource\n");
+dev_attr_err:
+ kfree(dev_attr);
return -1;
}
@@ -253,6 +280,80 @@
}
/**
+ * iser_create_frwr_pool - Creates pool of fast_reg descriptors
+ * for fast registration work requests.
+ * returns 0 on success, or errno code on failure
+ */
+int iser_create_frwr_pool(struct iser_conn *ib_conn, unsigned cmds_max)
+{
+ struct iser_device *device = ib_conn->device;
+ struct fast_reg_descriptor *desc;
+ int i, ret;
+
+ INIT_LIST_HEAD(&ib_conn->fastreg.frwr.pool);
+ ib_conn->fastreg.frwr.pool_size = 0;
+ for (i = 0; i < cmds_max; i++) {
+ desc = kmalloc(sizeof(*desc), GFP_KERNEL);
+ if (!desc) {
+ iser_err("Failed to allocate a new fast_reg descriptor\n");
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ desc->data_frpl = ib_alloc_fast_reg_page_list(device->ib_device,
+ ISCSI_ISER_SG_TABLESIZE + 1);
+ if (IS_ERR(desc->data_frpl)) {
+ ret = PTR_ERR(desc->data_frpl);
+ iser_err("Failed to allocate ib_fast_reg_page_list err=%d\n", ret);
+ goto err;
+ }
+
+ desc->data_mr = ib_alloc_fast_reg_mr(device->pd,
+ ISCSI_ISER_SG_TABLESIZE + 1);
+ if (IS_ERR(desc->data_mr)) {
+ ret = PTR_ERR(desc->data_mr);
+ iser_err("Failed to allocate ib_fast_reg_mr err=%d\n", ret);
+ ib_free_fast_reg_page_list(desc->data_frpl);
+ goto err;
+ }
+ desc->valid = true;
+ list_add_tail(&desc->list, &ib_conn->fastreg.frwr.pool);
+ ib_conn->fastreg.frwr.pool_size++;
+ }
+
+ return 0;
+err:
+ iser_free_frwr_pool(ib_conn);
+ return ret;
+}
+
+/**
+ * iser_free_frwr_pool - releases the pool of fast_reg descriptors
+ */
+void iser_free_frwr_pool(struct iser_conn *ib_conn)
+{
+ struct fast_reg_descriptor *desc, *tmp;
+ int i = 0;
+
+ if (list_empty(&ib_conn->fastreg.frwr.pool))
+ return;
+
+ iser_info("freeing conn %p frwr pool\n", ib_conn);
+
+ list_for_each_entry_safe(desc, tmp, &ib_conn->fastreg.frwr.pool, list) {
+ list_del(&desc->list);
+ ib_free_fast_reg_page_list(desc->data_frpl);
+ ib_dereg_mr(desc->data_mr);
+ kfree(desc);
+ ++i;
+ }
+
+ if (i < ib_conn->fastreg.frwr.pool_size)
+ iser_warn("pool still has %d regions registered\n",
+ ib_conn->fastreg.frwr.pool_size - i);
+}
+
+/**
* iser_create_ib_conn_res - Queue-Pair (QP)
*
* returns 0 on success, -1 on failure
@@ -707,7 +808,7 @@
mem_reg->rkey = mem->fmr->rkey;
mem_reg->len = page_vec->length * SIZE_4K;
mem_reg->va = io_addr;
- mem_reg->is_fmr = 1;
+ mem_reg->is_mr = 1;
mem_reg->mem_h = (void *)mem;
mem_reg->va += page_vec->offset;
@@ -734,7 +835,7 @@
struct iser_mem_reg *reg = &iser_task->rdma_regd[cmd_dir].reg;
int ret;
- if (!reg->is_fmr)
+ if (!reg->is_mr)
return;
iser_dbg("PHYSICAL Mem.Unregister mem_h %p\n",reg->mem_h);
@@ -746,6 +847,23 @@
reg->mem_h = NULL;
}
+void iser_unreg_mem_frwr(struct iscsi_iser_task *iser_task,
+ enum iser_data_dir cmd_dir)
+{
+ struct iser_mem_reg *reg = &iser_task->rdma_regd[cmd_dir].reg;
+ struct iser_conn *ib_conn = iser_task->iser_conn->ib_conn;
+ struct fast_reg_descriptor *desc = reg->mem_h;
+
+ if (!reg->is_mr)
+ return;
+
+ reg->mem_h = NULL;
+ reg->is_mr = 0;
+ spin_lock_bh(&ib_conn->lock);
+ list_add_tail(&desc->list, &ib_conn->fastreg.frwr.pool);
+ spin_unlock_bh(&ib_conn->lock);
+}
+
int iser_post_recvl(struct iser_conn *ib_conn)
{
struct ib_recv_wr rx_wr, *rx_wr_failed;
@@ -867,7 +985,11 @@
if (wc.status == IB_WC_SUCCESS) {
if (wc.opcode == IB_WC_SEND)
iser_snd_completion(tx_desc, ib_conn);
- else
+ else if (wc.opcode == IB_WC_LOCAL_INV ||
+ wc.opcode == IB_WC_FAST_REG_MR) {
+ atomic_dec(&ib_conn->post_send_buf_count);
+ continue;
+ } else
iser_err("expected opcode %d got %d\n",
IB_WC_SEND, wc.opcode);
} else {
