Revert "ib_srpt: Convert to percpu_ida tag allocation"

This reverts commit 0fd10721fe3664f7549e74af9d28a509c9a68719.

That patch causes the ib_srpt driver to crash as soon as the first SCSI
command is received:

  kernel BUG at drivers/infiniband/ulp/srpt/ib_srpt.c:1439!
  invalid opcode: 0000 [#1] SMP
  Workqueue: target_completion target_complete_ok_work [target_core_mod]
  RIP: srpt_queue_response+0x437/0x4a0 [ib_srpt]
  Call Trace:
    srpt_queue_data_in+0x9/0x10 [ib_srpt]
    target_complete_ok_work+0x152/0x2b0 [target_core_mod]
    process_one_work+0x197/0x480
    worker_thread+0x49/0x490
    kthread+0xea/0x100
    ret_from_fork+0x22/0x40

Aside from the crash, the shortcomings of that patch are as follows:

 - It makes the ib_srpt driver use I/O contexts allocated by
   transport_alloc_session_tags() but it does not initialize these I/O
   contexts properly.  All the initializations performed by
   srpt_alloc_ioctx() are skipped.

 - It swaps the order of the send ioctx allocation and the transition to
   RTR mode which is wrong.

 - The amount of memory that is needed for I/O contexts is doubled.

 - srpt_rdma_ch.free_list is no longer used but is not removed.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 0bd3cb2f3c671a21fefd57dbc4851a24daa61e82..8b42401d4795646019f4498ed909b306630f19ec 100644 (file)
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -1264,26 +1264,40 @@ free_mem:
  */
 static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
 {
-       struct se_session *se_sess;
        struct srpt_send_ioctx *ioctx;
-       int tag;
+       unsigned long flags;
 
        BUG_ON(!ch);
-       se_sess = ch->sess;
 
-       tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
-       if (tag < 0) {
-               pr_err("Unable to obtain tag for srpt_send_ioctx\n");
-               return NULL;
+       ioctx = NULL;
+       spin_lock_irqsave(&ch->spinlock, flags);
+       if (!list_empty(&ch->free_list)) {
+               ioctx = list_first_entry(&ch->free_list,
+                                        struct srpt_send_ioctx, free_list);
+               list_del(&ioctx->free_list);
        }
-       ioctx = &((struct srpt_send_ioctx *)se_sess->sess_cmd_map)[tag];
-       memset(ioctx, 0, sizeof(struct srpt_send_ioctx));
-       ioctx->ch = ch;
+       spin_unlock_irqrestore(&ch->spinlock, flags);
+
+       if (!ioctx)
+               return ioctx;
+
+       BUG_ON(ioctx->ch != ch);
        spin_lock_init(&ioctx->spinlock);
        ioctx->state = SRPT_STATE_NEW;
+       ioctx->n_rbuf = 0;
+       ioctx->rbufs = NULL;
+       ioctx->n_rdma = 0;
+       ioctx->n_rdma_wrs = 0;
+       ioctx->rdma_wrs = NULL;
+       ioctx->mapped_sg_count = 0;
        init_completion(&ioctx->tx_done);
-
-       ioctx->cmd.map_tag = tag;
+       ioctx->queue_status_only = false;
+       /*
+        * transport_init_se_cmd() does not initialize all fields, so do it
+        * here.
+        */
+       memset(&ioctx->cmd, 0, sizeof(ioctx->cmd));
+       memset(&ioctx->sense_data, 0, sizeof(ioctx->sense_data));
 
        return ioctx;
 }
@@ -2021,7 +2035,7 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
        struct ib_cm_rep_param *rep_param;
        struct srpt_rdma_ch *ch, *tmp_ch;
        u32 it_iu_len;
-       int ret = 0;
+       int i, ret = 0;
        unsigned char *p;
 
        WARN_ON_ONCE(irqs_disabled());
@@ -2143,6 +2157,12 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
        if (!ch->ioctx_ring)
                goto free_ch;
 
+       INIT_LIST_HEAD(&ch->free_list);
+       for (i = 0; i < ch->rq_size; i++) {
+               ch->ioctx_ring[i]->ch = ch;
+               list_add_tail(&ch->ioctx_ring[i]->free_list, &ch->free_list);
+       }
+
        ret = srpt_create_ch_ib(ch);
        if (ret) {
                rej->reason = cpu_to_be32(
@@ -2173,8 +2193,7 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
        p = &ch->sess_name[0];
 
 try_again:
-       ch->sess = target_alloc_session(&sport->port_tpg_1, ch->rq_size,
-                                       sizeof(struct srpt_send_ioctx),
+       ch->sess = target_alloc_session(&sport->port_tpg_1, 0, 0,
                                        TARGET_PROT_NORMAL, p, ch, NULL);
        if (IS_ERR(ch->sess)) {
                pr_info("Rejected login because no ACL has been"
@@ -2881,7 +2900,7 @@ static void srpt_release_cmd(struct se_cmd *se_cmd)
        struct srpt_send_ioctx *ioctx = container_of(se_cmd,
                                struct srpt_send_ioctx, cmd);
        struct srpt_rdma_ch *ch = ioctx->ch;
-       struct se_session *se_sess = ch->sess;
+       unsigned long flags;
 
        WARN_ON(ioctx->state != SRPT_STATE_DONE);
        WARN_ON(ioctx->mapped_sg_count != 0);
@@ -2892,7 +2911,9 @@ static void srpt_release_cmd(struct se_cmd *se_cmd)
                ioctx->n_rbuf = 0;
        }
 
-       percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
+       spin_lock_irqsave(&ch->spinlock, flags);
+       list_add(&ioctx->free_list, &ch->free_list);
+       spin_unlock_irqrestore(&ch->spinlock, flags);
 }
 
 /**

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h
index ca288f019315cda7142169ddbe5269772a7f398c..af9b8b527340c80f4c8af515cc4aa641a5c5b426 100644 (file)
--- a/drivers/infiniband/ulp/srpt/ib_srpt.h
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.h
@@ -179,6 +179,7 @@ struct srpt_recv_ioctx {
  * struct srpt_send_ioctx - SRPT send I/O context.
  * @ioctx:       See above.
  * @ch:          Channel pointer.
+ * @free_list:   Node in srpt_rdma_ch.free_list.
  * @n_rbuf:      Number of data buffers in the received SRP command.
  * @rbufs:       Pointer to SRP data buffer array.
  * @single_rbuf: SRP data buffer if the command has only a single buffer.
@@ -201,6 +202,7 @@ struct srpt_send_ioctx {
        struct srp_direct_buf   *rbufs;
        struct srp_direct_buf   single_rbuf;
        struct scatterlist      *sg;
+       struct list_head        free_list;
        spinlock_t              spinlock;
        enum srpt_command_state state;
        struct se_cmd           cmd;