Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending

Pull SCSI target updates from Nicholas Bellinger:
 "Things have been quiet this round with mostly bugfixes, percpu
  conversions, and other minor iscsi-target conformance testing changes.

  The highlights include:

   - Add demo_mode_discovery attribute for iscsi-target (Thomas)
   - Convert tcm_fc(FCoE) to use percpu-ida pre-allocation
   - Add send completion interrupt coalescing for ib_isert
   - Convert target-core to use percpu-refcounting for se_lun
   - Fix mutex_trylock usage bug in iscsit_increment_maxcmdsn
   - tcm_loop updates (Hannes)
   - target-core ALUA cleanups + prep for v3.14 SCSI Referrals support (Hannes)

  v3.14 is currently shaping to be a busy development cycle in target
  land, with initial support for T10 Referrals and T10 DIF currently on
  the roadmap"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (40 commits)
  iscsi-target: chap auth shouldn't match username with trailing garbage
  iscsi-target: fix extract_param to handle buffer length corner case
  iscsi-target: Expose default_erl as TPG attribute
  target_core_configfs: split up ALUA supported states
  target_core_alua: Make supported states configurable
  target_core_alua: Store supported ALUA states
  target_core_alua: Rename ALUA_ACCESS_STATE_OPTIMIZED
  target_core_alua: spellcheck
  target core: rename (ex,im)plict -> (ex,im)plicit
  percpu-refcount: Add percpu-refcount.o to obj-y
  iscsi-target: Do not reject non-immediate CmdSNs exceeding MaxCmdSN
  iscsi-target: Convert iscsi_session statistics to atomic_long_t
  target: Convert se_device statistics to atomic_long_t
  target: Fix delayed Task Aborted Status (TAS) handling bug
  iscsi-target: Reject unsupported multi PDU text command sequence
  ib_isert: Avoid duplicate iscsit_increment_maxcmdsn call
  iscsi-target: Fix mutex_trylock usage in iscsit_increment_maxcmdsn
  target: Core does not need blkdev.h
  target: Pass through I/O topology for block backstores
  iser-target: Avoid using FRMR for single dma entry requests
  ...

1 files changed, 71 insertions, 28 deletions

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 6df23502059a..6be57c38638d 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -22,6 +22,7 @@
 #include <linux/socket.h>
 #include <linux/in.h>
 #include <linux/in6.h>
+#include <linux/llist.h>
 #include <rdma/ib_verbs.h>
 #include <rdma/rdma_cm.h>
 #include <target/target_core_base.h>
@@ -489,6 +490,7 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
         kref_init(&isert_conn->conn_kref);
         kref_get(&isert_conn->conn_kref);
         mutex_init(&isert_conn->conn_mutex);
+        mutex_init(&isert_conn->conn_comp_mutex);
         spin_lock_init(&isert_conn->conn_lock);
 
         cma_id->context = isert_conn;
@@ -843,14 +845,32 @@ isert_init_tx_hdrs(struct isert_conn *isert_conn,
 }
 
 static void
-isert_init_send_wr(struct isert_cmd *isert_cmd, struct ib_send_wr *send_wr)
+isert_init_send_wr(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd,
+                   struct ib_send_wr *send_wr, bool coalesce)
 {
+        struct iser_tx_desc *tx_desc = &isert_cmd->tx_desc;
+
         isert_cmd->rdma_wr.iser_ib_op = ISER_IB_SEND;
         send_wr->wr_id = (unsigned long)&isert_cmd->tx_desc;
         send_wr->opcode = IB_WR_SEND;
-        send_wr->send_flags = IB_SEND_SIGNALED;
-        send_wr->sg_list = &isert_cmd->tx_desc.tx_sg[0];
+        send_wr->sg_list = &tx_desc->tx_sg[0];
         send_wr->num_sge = isert_cmd->tx_desc.num_sge;
+        /*
+         * Coalesce send completion interrupts by only setting IB_SEND_SIGNALED
+         * bit for every ISERT_COMP_BATCH_COUNT number of ib_post_send() calls.
+         */
+        mutex_lock(&isert_conn->conn_comp_mutex);
+        if (coalesce &&
+            ++isert_conn->conn_comp_batch < ISERT_COMP_BATCH_COUNT) {
+                llist_add(&tx_desc->comp_llnode, &isert_conn->conn_comp_llist);
+                mutex_unlock(&isert_conn->conn_comp_mutex);
+                return;
+        }
+        isert_conn->conn_comp_batch = 0;
+        tx_desc->comp_llnode_batch = llist_del_all(&isert_conn->conn_comp_llist);
+        mutex_unlock(&isert_conn->conn_comp_mutex);
+
+        send_wr->send_flags = IB_SEND_SIGNALED;
 }
 
 static int
@@ -1582,8 +1602,8 @@ isert_response_completion(struct iser_tx_desc *tx_desc,
 }
 
 static void
-isert_send_completion(struct iser_tx_desc *tx_desc,
-                      struct isert_conn *isert_conn)
+__isert_send_completion(struct iser_tx_desc *tx_desc,
+                        struct isert_conn *isert_conn)
 {
         struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
         struct isert_cmd *isert_cmd = tx_desc->isert_cmd;
@@ -1624,6 +1644,24 @@ isert_send_completion(struct iser_tx_desc *tx_desc,
 }
 
 static void
+isert_send_completion(struct iser_tx_desc *tx_desc,
+                      struct isert_conn *isert_conn)
+{
+        struct llist_node *llnode = tx_desc->comp_llnode_batch;
+        struct iser_tx_desc *t;
+        /*
+         * Drain coalesced completion llist starting from comp_llnode_batch
+         * setup in isert_init_send_wr(), and then complete trailing tx_desc.
+         */
+        while (llnode) {
+                t = llist_entry(llnode, struct iser_tx_desc, comp_llnode);
+                llnode = llist_next(llnode);
+                __isert_send_completion(t, isert_conn);
+        }
+        __isert_send_completion(tx_desc, isert_conn);
+}
+
+static void
 isert_cq_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn)
 {
         struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
@@ -1793,7 +1831,7 @@ isert_put_response(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
                 isert_cmd->tx_desc.num_sge = 2;
         }
 
-        isert_init_send_wr(isert_cmd, send_wr);
+        isert_init_send_wr(isert_conn, isert_cmd, send_wr, true);
 
         pr_debug("Posting SCSI Response IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");
 
@@ -1813,7 +1851,7 @@ isert_put_nopin(struct iscsi_cmd *cmd, struct iscsi_conn *conn,
                                &isert_cmd->tx_desc.iscsi_header,
                                nopout_response);
         isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
-        isert_init_send_wr(isert_cmd, send_wr);
+        isert_init_send_wr(isert_conn, isert_cmd, send_wr, false);
 
         pr_debug("Posting NOPIN Response IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");
 
@@ -1831,7 +1869,7 @@ isert_put_logout_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
         iscsit_build_logout_rsp(cmd, conn, (struct iscsi_logout_rsp *)
                                 &isert_cmd->tx_desc.iscsi_header);
         isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
-        isert_init_send_wr(isert_cmd, send_wr);
+        isert_init_send_wr(isert_conn, isert_cmd, send_wr, false);
 
         pr_debug("Posting Logout Response IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");
 
@@ -1849,7 +1887,7 @@ isert_put_tm_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
         iscsit_build_task_mgt_rsp(cmd, conn, (struct iscsi_tm_rsp *)
                                   &isert_cmd->tx_desc.iscsi_header);
         isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
-        isert_init_send_wr(isert_cmd, send_wr);
+        isert_init_send_wr(isert_conn, isert_cmd, send_wr, false);
 
         pr_debug("Posting Task Management Response IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");
 
@@ -1881,7 +1919,7 @@ isert_put_reject(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
         tx_dsg->lkey    = isert_conn->conn_mr->lkey;
         isert_cmd->tx_desc.num_sge = 2;
 
-        isert_init_send_wr(isert_cmd, send_wr);
+        isert_init_send_wr(isert_conn, isert_cmd, send_wr, false);
 
         pr_debug("Posting Reject IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");
 
@@ -1921,7 +1959,7 @@ isert_put_text_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
                 tx_dsg->lkey    = isert_conn->conn_mr->lkey;
                 isert_cmd->tx_desc.num_sge = 2;
         }
-        isert_init_send_wr(isert_cmd, send_wr);
+        isert_init_send_wr(isert_conn, isert_cmd, send_wr, false);
 
         pr_debug("Posting Text Response IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");
 
@@ -1991,8 +2029,6 @@ isert_map_rdma(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
 
         if (wr->iser_ib_op == ISER_IB_RDMA_WRITE) {
                 data_left = se_cmd->data_length;
-                iscsit_increment_maxcmdsn(cmd, conn->sess);
-                cmd->stat_sn = conn->stat_sn++;
         } else {
                 sg_off = cmd->write_data_done / PAGE_SIZE;
                 data_left = se_cmd->data_length - cmd->write_data_done;
@@ -2204,8 +2240,6 @@ isert_reg_rdma_frwr(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
 
         if (wr->iser_ib_op == ISER_IB_RDMA_WRITE) {
                 data_left = se_cmd->data_length;
-                iscsit_increment_maxcmdsn(cmd, conn->sess);
-                cmd->stat_sn = conn->stat_sn++;
         } else {
                 sg_off = cmd->write_data_done / PAGE_SIZE;
                 data_left = se_cmd->data_length - cmd->write_data_done;
@@ -2259,18 +2293,26 @@ isert_reg_rdma_frwr(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
         data_len = min(data_left, rdma_write_max);
         wr->cur_rdma_length = data_len;
 
-        spin_lock_irqsave(&isert_conn->conn_lock, flags);
-        fr_desc = list_first_entry(&isert_conn->conn_frwr_pool,
-                                   struct fast_reg_descriptor, list);
-        list_del(&fr_desc->list);
-        spin_unlock_irqrestore(&isert_conn->conn_lock, flags);
-        wr->fr_desc = fr_desc;
+        /* if there is a single dma entry, dma mr is sufficient */
+        if (count == 1) {
+                ib_sge->addr = ib_sg_dma_address(ib_dev, &sg_start[0]);
+                ib_sge->length = ib_sg_dma_len(ib_dev, &sg_start[0]);
+                ib_sge->lkey = isert_conn->conn_mr->lkey;
+                wr->fr_desc = NULL;
+        } else {
+                spin_lock_irqsave(&isert_conn->conn_lock, flags);
+                fr_desc = list_first_entry(&isert_conn->conn_frwr_pool,
+                                           struct fast_reg_descriptor, list);
+                list_del(&fr_desc->list);
+                spin_unlock_irqrestore(&isert_conn->conn_lock, flags);
+                wr->fr_desc = fr_desc;
 
-        ret = isert_fast_reg_mr(fr_desc, isert_cmd, isert_conn,
-                          ib_sge, offset, data_len);
-        if (ret) {
-                list_add_tail(&fr_desc->list, &isert_conn->conn_frwr_pool);
-                goto unmap_sg;
+                ret = isert_fast_reg_mr(fr_desc, isert_cmd, isert_conn,
+                                  ib_sge, offset, data_len);
+                if (ret) {
+                        list_add_tail(&fr_desc->list, &isert_conn->conn_frwr_pool);
+                        goto unmap_sg;
+                }
         }
 
         return 0;
@@ -2306,10 +2348,11 @@ isert_put_datain(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
          * Build isert_conn->tx_desc for iSCSI response PDU and attach
          */
         isert_create_send_desc(isert_conn, isert_cmd, &isert_cmd->tx_desc);
-        iscsit_build_rsp_pdu(cmd, conn, false, (struct iscsi_scsi_rsp *)
+        iscsit_build_rsp_pdu(cmd, conn, true, (struct iscsi_scsi_rsp *)
                              &isert_cmd->tx_desc.iscsi_header);
         isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
-        isert_init_send_wr(isert_cmd, &isert_cmd->tx_desc.send_wr);
+        isert_init_send_wr(isert_conn, isert_cmd,
+                           &isert_cmd->tx_desc.send_wr, true);
 
         atomic_inc(&isert_conn->post_send_buf_count);