[SCSI] libiscsi: make can_queue configurable

This patch allows us to set can_queue and cmds_per_lun from userspace
when we create the session/host. From there we can set it on a per
target basis. The patch fully converts iscsi_tcp, but only hooks
up ib_iser for cmd_per_lun since it currently has a lots of preallocations
based on can_queue.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Cc: Roland Dreier <rdreier@cisco.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

6 files changed, 45 insertions, 9 deletions

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index 9782190a9ee5..bed583c426e6 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -373,7 +373,8 @@ static struct iscsi_transport iscsi_iser_transport;
 static struct iscsi_cls_session *
 iscsi_iser_session_create(struct iscsi_transport *iscsit,
                          struct scsi_transport_template *scsit,
-                          uint32_t initial_cmdsn, uint32_t *hostno)
+                         uint16_t cmds_max, uint16_t qdepth,
+                         uint32_t initial_cmdsn, uint32_t *hostno)
 {
         struct iscsi_cls_session *cls_session;
         struct iscsi_session *session;
@@ -384,7 +385,13 @@ iscsi_iser_session_create(struct iscsi_transport *iscsit,
         struct iscsi_iser_cmd_task *iser_ctask;
         struct iser_desc *desc;
 
+        /*
+         * we do not support setting can_queue cmd_per_lun from userspace yet
+         * because we preallocate so many resources
+         */
         cls_session = iscsi_session_setup(iscsit, scsit,
+                                          ISCSI_DEF_XMIT_CMDS_MAX,
+                                          ISCSI_MAX_CMD_PER_LUN,
                                           sizeof(struct iscsi_iser_cmd_task),
                                           sizeof(struct iser_desc),
                                           initial_cmdsn, &hn);
@@ -543,7 +550,7 @@ iscsi_iser_ep_disconnect(__u64 ep_handle)
 static struct scsi_host_template iscsi_iser_sht = {
         .name                   = "iSCSI Initiator over iSER, v." DRV_VER,
         .queuecommand           = iscsi_queuecommand,
-        .can_queue              = ISCSI_XMIT_CMDS_MAX - 1,
+        .can_queue              = ISCSI_DEF_XMIT_CMDS_MAX - 1,
         .sg_tablesize           = ISCSI_ISER_SG_TABLESIZE,
         .max_sectors            = 1024,
         .cmd_per_lun            = ISCSI_MAX_CMD_PER_LUN,
diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.h b/drivers/infiniband/ulp/iser/iscsi_iser.h
index 8960196ffb0f..e2353701e8bb 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.h
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.h
@@ -98,7 +98,7 @@
 #define ISER_MAX_TX_MISC_PDUS           6 /* NOOP_OUT(2), TEXT(1),         *
                                            * SCSI_TMFUNC(2), LOGOUT(1) */
 
-#define ISER_QP_MAX_RECV_DTOS           (ISCSI_XMIT_CMDS_MAX + \
+#define ISER_QP_MAX_RECV_DTOS           (ISCSI_DEF_XMIT_CMDS_MAX + \
                                         ISER_MAX_RX_MISC_PDUS    +  \
                                         ISER_MAX_TX_MISC_PDUS)
 
@@ -110,7 +110,7 @@
 
 #define ISER_INFLIGHT_DATAOUTS          8
 
-#define ISER_QP_MAX_REQ_DTOS            (ISCSI_XMIT_CMDS_MAX *    \
+#define ISER_QP_MAX_REQ_DTOS            (ISCSI_DEF_XMIT_CMDS_MAX *    \
                                         (1 + ISER_INFLIGHT_DATAOUTS) + \
                                         ISER_MAX_TX_MISC_PDUS        + \
                                         ISER_MAX_RX_MISC_PDUS)
diff --git a/drivers/infiniband/ulp/iser/iser_verbs.c b/drivers/infiniband/ulp/iser/iser_verbs.c
index 3702e2375553..2044de1164ac 100644
--- a/drivers/infiniband/ulp/iser/iser_verbs.c
+++ b/drivers/infiniband/ulp/iser/iser_verbs.c
@@ -155,8 +155,8 @@ static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
         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.pool_size         = ISCSI_DEF_XMIT_CMDS_MAX * 2;
+        params.dirty_watermark   = ISCSI_DEF_XMIT_CMDS_MAX;
         params.cache             = 0;
         params.flush_function    = NULL;
         params.access            = (IB_ACCESS_LOCAL_WRITE  |
diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 8edcfddc0baf..eca4d611dd49 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -2114,6 +2114,7 @@ iscsi_conn_get_stats(struct iscsi_cls_conn *cls_conn, struct iscsi_stats *stats)
 static struct iscsi_cls_session *
 iscsi_tcp_session_create(struct iscsi_transport *iscsit,
                          struct scsi_transport_template *scsit,
+                         uint16_t cmds_max, uint16_t qdepth,
                          uint32_t initial_cmdsn, uint32_t *hostno)
 {
         struct iscsi_cls_session *cls_session;
@@ -2121,7 +2122,7 @@ iscsi_tcp_session_create(struct iscsi_transport *iscsit,
         uint32_t hn;
         int cmd_i;
 
-        cls_session = iscsi_session_setup(iscsit, scsit,
+        cls_session = iscsi_session_setup(iscsit, scsit, cmds_max, qdepth,
                                          sizeof(struct iscsi_tcp_cmd_task),
                                          sizeof(struct iscsi_tcp_mgmt_task),
                                          initial_cmdsn, &hn);
@@ -2164,7 +2165,7 @@ static struct scsi_host_template iscsi_sht = {
         .name                   = "iSCSI Initiator over TCP/IP",
         .queuecommand           = iscsi_queuecommand,
         .change_queue_depth     = iscsi_change_queue_depth,
-        .can_queue              = ISCSI_XMIT_CMDS_MAX - 1,
+        .can_queue              = ISCSI_DEF_XMIT_CMDS_MAX - 1,
         .sg_tablesize           = ISCSI_SG_TABLESIZE,
         .max_sectors            = 0xFFFF,
         .cmd_per_lun            = ISCSI_DEF_CMD_PER_LUN,
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 938f527cd81a..1632866f52cc 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1330,6 +1330,10 @@ EXPORT_SYMBOL_GPL(iscsi_pool_free);
  * iscsi_session_setup - create iscsi cls session and host and session
  * @scsit: scsi transport template
  * @iscsit: iscsi transport template
+ * @cmds_max: scsi host can queue
+ * @qdepth: scsi host cmds per lun
+ * @cmd_task_size: LLD ctask private data size
+ * @mgmt_task_size: LLD mtask private data size
  * @initial_cmdsn: initial CmdSN
  * @hostno: host no allocated
  *
@@ -1339,6 +1343,7 @@ EXPORT_SYMBOL_GPL(iscsi_pool_free);
 struct iscsi_cls_session *
 iscsi_session_setup(struct iscsi_transport *iscsit,
                     struct scsi_transport_template *scsit,
+                    uint16_t cmds_max, uint16_t qdepth,
                     int cmd_task_size, int mgmt_task_size,
                     uint32_t initial_cmdsn, uint32_t *hostno)
 {
@@ -1347,11 +1352,32 @@ iscsi_session_setup(struct iscsi_transport *iscsit,
         struct iscsi_cls_session *cls_session;
         int cmd_i;
 
+        if (qdepth > ISCSI_MAX_CMD_PER_LUN || qdepth < 1) {
+                if (qdepth != 0)
+                        printk(KERN_ERR "iscsi: invalid queue depth of %d. "
+                              "Queue depth must be between 1 and %d.\n",
+                              qdepth, ISCSI_MAX_CMD_PER_LUN);
+                qdepth = ISCSI_DEF_CMD_PER_LUN;
+        }
+
+        if (cmds_max < 2 || (cmds_max & (cmds_max - 1)) ||
+            cmds_max >= ISCSI_MGMT_ITT_OFFSET) {
+                if (cmds_max != 0)
+                        printk(KERN_ERR "iscsi: invalid can_queue of %d. "
+                               "can_queue must be a power of 2 and between "
+                               "2 and %d - setting to %d.\n", cmds_max,
+                               ISCSI_MGMT_ITT_OFFSET, ISCSI_DEF_XMIT_CMDS_MAX);
+                cmds_max = ISCSI_DEF_XMIT_CMDS_MAX;
+        }
+
         shost = scsi_host_alloc(iscsit->host_template,
                                 hostdata_privsize(sizeof(*session)));
         if (!shost)
                 return NULL;
 
+        /* the iscsi layer takes one task for reserve */
+        shost->can_queue = cmds_max - 1;
+        shost->cmd_per_lun = qdepth;
         shost->max_id = 1;
         shost->max_channel = 0;
         shost->max_lun = iscsit->max_lun;
@@ -1365,7 +1391,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit,
         session->host = shost;
         session->state = ISCSI_STATE_FREE;
         session->mgmtpool_max = ISCSI_MGMT_CMDS_MAX;
-        session->cmds_max = ISCSI_XMIT_CMDS_MAX;
+        session->cmds_max = cmds_max;
         session->cmdsn = initial_cmdsn;
         session->exp_cmdsn = initial_cmdsn + 1;
         session->max_cmdsn = initial_cmdsn + 1;
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 341d4fb5c6f8..859bd2100856 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -814,6 +814,8 @@ iscsi_if_create_session(struct iscsi_internal *priv, struct iscsi_uevent *ev)
         uint32_t hostno;
 
         session = transport->create_session(transport, &priv->t,
+                                            ev->u.c_session.cmds_max,
+                                            ev->u.c_session.queue_depth,
                                             ev->u.c_session.initial_cmdsn,
                                             &hostno);
         if (!session)