IB/srpt: Simplify srpt_handle_tsk_mgmt()

Let the target core check task existence instead of the SRP target
driver. Additionally, let the target core check the validity of the
task management request instead of the ib_srpt driver.

This patch fixes the following kernel crash:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
IP: [<ffffffffa0565f37>] srpt_handle_new_iu+0x6d7/0x790 [ib_srpt]
Oops: 0002 [#1] SMP
Call Trace:
 [<ffffffffa05660ce>] srpt_process_completion+0xde/0x570 [ib_srpt]
 [<ffffffffa056669f>] srpt_compl_thread+0x13f/0x160 [ib_srpt]
 [<ffffffff8109726f>] kthread+0xcf/0xe0
 [<ffffffff81613cfc>] ret_from_fork+0x7c/0xb0

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Fixes: 3e4f574857ee ("ib_srpt: Convert TMR path to target_submit_tmr")
Tested-by: Alex Estrin <alex.estrin@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 0c37fee363b1d60eb3dd63ebfdc6330b2e14b562..4328679a67a76792694a3e1169bc4e7bdac10d2f 100644 (file)
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -1670,47 +1670,6 @@ send_sense:
        return -1;
 }
 
-/**
- * srpt_rx_mgmt_fn_tag() - Process a task management function by tag.
- * @ch: RDMA channel of the task management request.
- * @fn: Task management function to perform.
- * @req_tag: Tag of the SRP task management request.
- * @mgmt_ioctx: I/O context of the task management request.
- *
- * Returns zero if the target core will process the task management
- * request asynchronously.
- *
- * Note: It is assumed that the initiator serializes tag-based task management
- * requests.
- */
-static int srpt_rx_mgmt_fn_tag(struct srpt_send_ioctx *ioctx, u64 tag)
-{
-       struct srpt_device *sdev;
-       struct srpt_rdma_ch *ch;
-       struct srpt_send_ioctx *target;
-       int ret, i;
-
-       ret = -EINVAL;
-       ch = ioctx->ch;
-       BUG_ON(!ch);
-       BUG_ON(!ch->sport);
-       sdev = ch->sport->sdev;
-       BUG_ON(!sdev);
-       spin_lock_irq(&sdev->spinlock);
-       for (i = 0; i < ch->rq_size; ++i) {
-               target = ch->ioctx_ring[i];
-               if (target->cmd.se_lun == ioctx->cmd.se_lun &&
-                   target->cmd.tag == tag &&
-                   srpt_get_cmd_state(target) != SRPT_STATE_DONE) {
-                       ret = 0;
-                       /* now let the target core abort &target->cmd; */
-                       break;
-               }
-       }
-       spin_unlock_irq(&sdev->spinlock);
-       return ret;
-}
-
 static int srp_tmr_to_tcm(int fn)
 {
        switch (fn) {
@@ -1745,7 +1704,6 @@ static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
        struct se_cmd *cmd;
        struct se_session *sess = ch->sess;
        uint64_t unpacked_lun;
-       uint32_t tag = 0;
        int tcm_tmr;
        int rc;
 
@@ -1761,25 +1719,10 @@ static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
        srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
        send_ioctx->cmd.tag = srp_tsk->tag;
        tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
-       if (tcm_tmr < 0) {
-               send_ioctx->cmd.se_tmr_req->response =
-                       TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
-               goto fail;
-       }
        unpacked_lun = srpt_unpack_lun((uint8_t *)&srp_tsk->lun,
                                       sizeof(srp_tsk->lun));
-
-       if (srp_tsk->tsk_mgmt_func == SRP_TSK_ABORT_TASK) {
-               rc = srpt_rx_mgmt_fn_tag(send_ioctx, srp_tsk->task_tag);
-               if (rc < 0) {
-                       send_ioctx->cmd.se_tmr_req->response =
-                                       TMR_TASK_DOES_NOT_EXIST;
-                       goto fail;
-               }
-               tag = srp_tsk->task_tag;
-       }
        rc = target_submit_tmr(&send_ioctx->cmd, sess, NULL, unpacked_lun,
-                               srp_tsk, tcm_tmr, GFP_KERNEL, tag,
+                               srp_tsk, tcm_tmr, GFP_KERNEL, srp_tsk->task_tag,
                                TARGET_SCF_ACK_KREF);
        if (rc != 0) {
                send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;