RDMA/siw: Fix handling of zero-sized Read and Receive Queues.

During connection setup, the application may choose to zero-size inbound
and outbound READ queues, as well as the Receive queue.  This patch fixes
handling of zero-sized queues, but not prevents it.

Kamal Heib says in an initial error report:

 When running the blktests over siw the following shift-out-of-bounds is
 reported, this is happening because the passed IRD or ORD from the ulp
 could be zero which will lead to unexpected behavior when calling
 roundup_pow_of_two(), fix that by blocking zero values of ORD or IRD.

   UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
   shift exponent 64 is too large for 64-bit type 'long unsigned int'
   CPU: 20 PID: 3957 Comm: kworker/u64:13 Tainted: G S     5.10.0-rc6 #2
   Hardware name: Dell Inc. PowerEdge R630/02C2CP, BIOS 2.1.5 04/11/2016
   Workqueue: iw_cm_wq cm_work_handler [iw_cm]
   Call Trace:
    dump_stack+0x99/0xcb
    ubsan_epilogue+0x5/0x40
    __ubsan_handle_shift_out_of_bounds.cold.11+0xb4/0xf3
    ? down_write+0x183/0x3d0
    siw_qp_modify.cold.8+0x2d/0x32 [siw]
    ? __local_bh_enable_ip+0xa5/0xf0
    siw_accept+0x906/0x1b60 [siw]
    ? xa_load+0x147/0x1f0
    ? siw_connect+0x17a0/0x17a0 [siw]
    ? lock_downgrade+0x700/0x700
    ? siw_get_base_qp+0x1c2/0x340 [siw]
    ? _raw_spin_unlock_irqrestore+0x39/0x40
    iw_cm_accept+0x1f4/0x430 [iw_cm]
    rdma_accept+0x3fa/0xb10 [rdma_cm]
    ? check_flush_dependency+0x410/0x410
    ? cma_rep_recv+0x570/0x570 [rdma_cm]
    nvmet_rdma_queue_connect+0x1a62/0x2680 [nvmet_rdma]
    ? nvmet_rdma_alloc_cmds+0xce0/0xce0 [nvmet_rdma]
    ? lock_release+0x56e/0xcc0
    ? lock_downgrade+0x700/0x700
    ? lock_downgrade+0x700/0x700
    ? __xa_alloc_cyclic+0xef/0x350
    ? __xa_alloc+0x2d0/0x2d0
    ? rdma_restrack_add+0xbe/0x2c0 [ib_core]
    ? __ww_mutex_die+0x190/0x190
    cma_cm_event_handler+0xf2/0x500 [rdma_cm]
    iw_conn_req_handler+0x910/0xcb0 [rdma_cm]
    ? _raw_spin_unlock_irqrestore+0x39/0x40
    ? trace_hardirqs_on+0x1c/0x150
    ? cma_ib_handler+0x8a0/0x8a0 [rdma_cm]
    ? __kasan_kmalloc.constprop.7+0xc1/0xd0
    cm_work_handler+0x121c/0x17a0 [iw_cm]
    ? iw_cm_reject+0x190/0x190 [iw_cm]
    ? trace_hardirqs_on+0x1c/0x150
    process_one_work+0x8fb/0x16c0
    ? pwq_dec_nr_in_flight+0x320/0x320
    worker_thread+0x87/0xb40
    ? __kthread_parkme+0xd1/0x1a0
    ? process_one_work+0x16c0/0x16c0
    kthread+0x35f/0x430
    ? kthread_mod_delayed_work+0x180/0x180
    ret_from_fork+0x22/0x30

Fixes: a531975279f3 ("rdma/siw: main include file")
Fixes: f29dd55b0236 ("rdma/siw: queue pair methods")
Fixes: 8b6a361b8c48 ("rdma/siw: receive path")
Fixes: b9be6f18cf9e ("rdma/siw: transmit path")
Fixes: 303ae1cdfdf7 ("rdma/siw: application interface")
Link: https://lore.kernel.org/r/20210108125845.1803-1-bmt@zurich.ibm.com
Reported-by: Kamal Heib <kamalheib1@gmail.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/sw/siw/siw.h b/drivers/infiniband/sw/siw/siw.h
index adda789..368959a 100644 (file)
--- a/drivers/infiniband/sw/siw/siw.h
+++ b/drivers/infiniband/sw/siw/siw.h
@@ -653,7 +653,7 @@ static inline struct siw_sqe *orq_get_free(struct siw_qp *qp)
 {
        struct siw_sqe *orq_e = orq_get_tail(qp);
 
-       if (orq_e && READ_ONCE(orq_e->flags) == 0)
+       if (READ_ONCE(orq_e->flags) == 0)
                return orq_e;
 
        return NULL;

diff --git a/drivers/infiniband/sw/siw/siw_qp.c b/drivers/infiniband/sw/siw/siw_qp.c
index 875d36d..ddb2e66 100644 (file)
--- a/drivers/infiniband/sw/siw/siw_qp.c
+++ b/drivers/infiniband/sw/siw/siw_qp.c
@@ -199,26 +199,26 @@ void siw_qp_llp_write_space(struct sock *sk)
 
 static int siw_qp_readq_init(struct siw_qp *qp, int irq_size, int orq_size)
 {
-       irq_size = roundup_pow_of_two(irq_size);
-       orq_size = roundup_pow_of_two(orq_size);
-
-       qp->attrs.irq_size = irq_size;
-       qp->attrs.orq_size = orq_size;
-
-       qp->irq = vzalloc(irq_size * sizeof(struct siw_sqe));
-       if (!qp->irq) {
-               siw_dbg_qp(qp, "irq malloc for %d failed\n", irq_size);
-               qp->attrs.irq_size = 0;
-               return -ENOMEM;
+       if (irq_size) {
+               irq_size = roundup_pow_of_two(irq_size);
+               qp->irq = vzalloc(irq_size * sizeof(struct siw_sqe));
+               if (!qp->irq) {
+                       qp->attrs.irq_size = 0;
+                       return -ENOMEM;
+               }
        }
-       qp->orq = vzalloc(orq_size * sizeof(struct siw_sqe));
-       if (!qp->orq) {
-               siw_dbg_qp(qp, "orq malloc for %d failed\n", orq_size);
-               qp->attrs.orq_size = 0;
-               qp->attrs.irq_size = 0;
-               vfree(qp->irq);
-               return -ENOMEM;
+       if (orq_size) {
+               orq_size = roundup_pow_of_two(orq_size);
+               qp->orq = vzalloc(orq_size * sizeof(struct siw_sqe));
+               if (!qp->orq) {
+                       qp->attrs.orq_size = 0;
+                       qp->attrs.irq_size = 0;
+                       vfree(qp->irq);
+                       return -ENOMEM;
+               }
        }
+       qp->attrs.irq_size = irq_size;
+       qp->attrs.orq_size = orq_size;
        siw_dbg_qp(qp, "ORD %d, IRD %d\n", orq_size, irq_size);
        return 0;
 }
@@ -288,13 +288,14 @@ int siw_qp_mpa_rts(struct siw_qp *qp, enum mpa_v2_ctrl ctrl)
        if (ctrl & MPA_V2_RDMA_WRITE_RTR)
                wqe->sqe.opcode = SIW_OP_WRITE;
        else if (ctrl & MPA_V2_RDMA_READ_RTR) {
-               struct siw_sqe *rreq;
+               struct siw_sqe *rreq = NULL;
 
                wqe->sqe.opcode = SIW_OP_READ;
 
                spin_lock(&qp->orq_lock);
 
-               rreq = orq_get_free(qp);
+               if (qp->attrs.orq_size)
+                       rreq = orq_get_free(qp);
                if (rreq) {
                        siw_read_to_orq(rreq, &wqe->sqe);
                        qp->orq_put++;
@@ -877,135 +878,88 @@ void siw_read_to_orq(struct siw_sqe *rreq, struct siw_sqe *sqe)
        rreq->num_sge = 1;
 }
 
-/*
- * Must be called with SQ locked.
- * To avoid complete SQ starvation by constant inbound READ requests,
- * the active IRQ will not be served after qp->irq_burst, if the
- * SQ has pending work.
- */
-int siw_activate_tx(struct siw_qp *qp)
+static int siw_activate_tx_from_sq(struct siw_qp *qp)
 {
-       struct siw_sqe *irqe, *sqe;
+       struct siw_sqe *sqe;
        struct siw_wqe *wqe = tx_wqe(qp);
        int rv = 1;
 
-       irqe = &qp->irq[qp->irq_get % qp->attrs.irq_size];
-
-       if (irqe->flags & SIW_WQE_VALID) {
-               sqe = sq_get_next(qp);
-
-               /*
-                * Avoid local WQE processing starvation in case
-                * of constant inbound READ request stream
-                */
-               if (sqe && ++qp->irq_burst >= SIW_IRQ_MAXBURST_SQ_ACTIVE) {
-                       qp->irq_burst = 0;
-                       goto skip_irq;
-               }
-               memset(wqe->mem, 0, sizeof(*wqe->mem) * SIW_MAX_SGE);
-               wqe->wr_status = SIW_WR_QUEUED;
-
-               /* start READ RESPONSE */
-               wqe->sqe.opcode = SIW_OP_READ_RESPONSE;
-               wqe->sqe.flags = 0;
-               if (irqe->num_sge) {
-                       wqe->sqe.num_sge = 1;
-                       wqe->sqe.sge[0].length = irqe->sge[0].length;
-                       wqe->sqe.sge[0].laddr = irqe->sge[0].laddr;
-                       wqe->sqe.sge[0].lkey = irqe->sge[0].lkey;
-               } else {
-                       wqe->sqe.num_sge = 0;
-               }
-
-               /* Retain original RREQ's message sequence number for
-                * potential error reporting cases.
-                */
-               wqe->sqe.sge[1].length = irqe->sge[1].length;
-
-               wqe->sqe.rkey = irqe->rkey;
-               wqe->sqe.raddr = irqe->raddr;
+       sqe = sq_get_next(qp);
+       if (!sqe)
+               return 0;
 
-               wqe->processed = 0;
-               qp->irq_get++;
+       memset(wqe->mem, 0, sizeof(*wqe->mem) * SIW_MAX_SGE);
+       wqe->wr_status = SIW_WR_QUEUED;
 
-               /* mark current IRQ entry free */
-               smp_store_mb(irqe->flags, 0);
+       /* First copy SQE to kernel private memory */
+       memcpy(&wqe->sqe, sqe, sizeof(*sqe));
 
+       if (wqe->sqe.opcode >= SIW_NUM_OPCODES) {
+               rv = -EINVAL;
                goto out;
        }
-       sqe = sq_get_next(qp);
-       if (sqe) {
-skip_irq:
-               memset(wqe->mem, 0, sizeof(*wqe->mem) * SIW_MAX_SGE);
-               wqe->wr_status = SIW_WR_QUEUED;
-
-               /* First copy SQE to kernel private memory */
-               memcpy(&wqe->sqe, sqe, sizeof(*sqe));
-
-               if (wqe->sqe.opcode >= SIW_NUM_OPCODES) {
+       if (wqe->sqe.flags & SIW_WQE_INLINE) {
+               if (wqe->sqe.opcode != SIW_OP_SEND &&
+                   wqe->sqe.opcode != SIW_OP_WRITE) {
                        rv = -EINVAL;
                        goto out;
                }
-               if (wqe->sqe.flags & SIW_WQE_INLINE) {
-                       if (wqe->sqe.opcode != SIW_OP_SEND &&
-                           wqe->sqe.opcode != SIW_OP_WRITE) {
-                               rv = -EINVAL;
-                               goto out;
-                       }
-                       if (wqe->sqe.sge[0].length > SIW_MAX_INLINE) {
-                               rv = -EINVAL;
-                               goto out;
-                       }
-                       wqe->sqe.sge[0].laddr = (uintptr_t)&wqe->sqe.sge[1];
-                       wqe->sqe.sge[0].lkey = 0;
-                       wqe->sqe.num_sge = 1;
+               if (wqe->sqe.sge[0].length > SIW_MAX_INLINE) {
+                       rv = -EINVAL;
+                       goto out;
                }
-               if (wqe->sqe.flags & SIW_WQE_READ_FENCE) {
-                       /* A READ cannot be fenced */
-                       if (unlikely(wqe->sqe.opcode == SIW_OP_READ ||
-                                    wqe->sqe.opcode ==
-                                            SIW_OP_READ_LOCAL_INV)) {
-                               siw_dbg_qp(qp, "cannot fence read\n");
-                               rv = -EINVAL;
-                               goto out;
-                       }
-                       spin_lock(&qp->orq_lock);
+               wqe->sqe.sge[0].laddr = (uintptr_t)&wqe->sqe.sge[1];
+               wqe->sqe.sge[0].lkey = 0;
+               wqe->sqe.num_sge = 1;
+       }
+       if (wqe->sqe.flags & SIW_WQE_READ_FENCE) {
+               /* A READ cannot be fenced */
+               if (unlikely(wqe->sqe.opcode == SIW_OP_READ ||
+                            wqe->sqe.opcode ==
+                                    SIW_OP_READ_LOCAL_INV)) {
+                       siw_dbg_qp(qp, "cannot fence read\n");
+                       rv = -EINVAL;
+                       goto out;
+               }
+               spin_lock(&qp->orq_lock);
 
-                       if (!siw_orq_empty(qp)) {
-                               qp->tx_ctx.orq_fence = 1;
-                               rv = 0;
-                       }
-                       spin_unlock(&qp->orq_lock);
+               if (qp->attrs.orq_size && !siw_orq_empty(qp)) {
+                       qp->tx_ctx.orq_fence = 1;
+                       rv = 0;
+               }
+               spin_unlock(&qp->orq_lock);
 
-               } else if (wqe->sqe.opcode == SIW_OP_READ ||
-                          wqe->sqe.opcode == SIW_OP_READ_LOCAL_INV) {
-                       struct siw_sqe *rreq;
+       } else if (wqe->sqe.opcode == SIW_OP_READ ||
+                  wqe->sqe.opcode == SIW_OP_READ_LOCAL_INV) {
+               struct siw_sqe *rreq;
 
-                       wqe->sqe.num_sge = 1;
+               if (unlikely(!qp->attrs.orq_size)) {
+                       /* We negotiated not to send READ req's */
+                       rv = -EINVAL;
+                       goto out;
+               }
+               wqe->sqe.num_sge = 1;
 
-                       spin_lock(&qp->orq_lock);
+               spin_lock(&qp->orq_lock);
 
-                       rreq = orq_get_free(qp);
-                       if (rreq) {
-                               /*
-                                * Make an immediate copy in ORQ to be ready
-                                * to process loopback READ reply
-                                */
-                               siw_read_to_orq(rreq, &wqe->sqe);
-                               qp->orq_put++;
-                       } else {
-                               qp->tx_ctx.orq_fence = 1;
-                               rv = 0;
-                       }
-                       spin_unlock(&qp->orq_lock);
+               rreq = orq_get_free(qp);
+               if (rreq) {
+                       /*
+                        * Make an immediate copy in ORQ to be ready
+                        * to process loopback READ reply
+                        */
+                       siw_read_to_orq(rreq, &wqe->sqe);
+                       qp->orq_put++;
+               } else {
+                       qp->tx_ctx.orq_fence = 1;
+                       rv = 0;
                }
-
-               /* Clear SQE, can be re-used by application */
-               smp_store_mb(sqe->flags, 0);
-               qp->sq_get++;
-       } else {
-               rv = 0;
+               spin_unlock(&qp->orq_lock);
        }
+
+       /* Clear SQE, can be re-used by application */
+       smp_store_mb(sqe->flags, 0);
+       qp->sq_get++;
 out:
        if (unlikely(rv < 0)) {
                siw_dbg_qp(qp, "error %d\n", rv);
@@ -1015,6 +969,65 @@ out:
 }
 
 /*
+ * Must be called with SQ locked.
+ * To avoid complete SQ starvation by constant inbound READ requests,
+ * the active IRQ will not be served after qp->irq_burst, if the
+ * SQ has pending work.
+ */
+int siw_activate_tx(struct siw_qp *qp)
+{
+       struct siw_sqe *irqe;
+       struct siw_wqe *wqe = tx_wqe(qp);
+
+       if (!qp->attrs.irq_size)
+               return siw_activate_tx_from_sq(qp);
+
+       irqe = &qp->irq[qp->irq_get % qp->attrs.irq_size];
+
+       if (!(irqe->flags & SIW_WQE_VALID))
+               return siw_activate_tx_from_sq(qp);
+
+       /*
+        * Avoid local WQE processing starvation in case
+        * of constant inbound READ request stream
+        */
+       if (sq_get_next(qp) && ++qp->irq_burst >= SIW_IRQ_MAXBURST_SQ_ACTIVE) {
+               qp->irq_burst = 0;
+               return siw_activate_tx_from_sq(qp);
+       }
+       memset(wqe->mem, 0, sizeof(*wqe->mem) * SIW_MAX_SGE);
+       wqe->wr_status = SIW_WR_QUEUED;
+
+       /* start READ RESPONSE */
+       wqe->sqe.opcode = SIW_OP_READ_RESPONSE;
+       wqe->sqe.flags = 0;
+       if (irqe->num_sge) {
+               wqe->sqe.num_sge = 1;
+               wqe->sqe.sge[0].length = irqe->sge[0].length;
+               wqe->sqe.sge[0].laddr = irqe->sge[0].laddr;
+               wqe->sqe.sge[0].lkey = irqe->sge[0].lkey;
+       } else {
+               wqe->sqe.num_sge = 0;
+       }
+
+       /* Retain original RREQ's message sequence number for
+        * potential error reporting cases.
+        */
+       wqe->sqe.sge[1].length = irqe->sge[1].length;
+
+       wqe->sqe.rkey = irqe->rkey;
+       wqe->sqe.raddr = irqe->raddr;
+
+       wqe->processed = 0;
+       qp->irq_get++;
+
+       /* mark current IRQ entry free */
+       smp_store_mb(irqe->flags, 0);
+
+       return 1;
+}
+
+/*
  * Check if current CQ state qualifies for calling CQ completion
  * handler. Must be called with CQ lock held.
  */

diff --git a/drivers/infiniband/sw/siw/siw_qp_rx.c b/drivers/infiniband/sw/siw/siw_qp_rx.c
index 4bd1f1f..60116f2 100644 (file)
--- a/drivers/infiniband/sw/siw/siw_qp_rx.c
+++ b/drivers/infiniband/sw/siw/siw_qp_rx.c
@@ -680,6 +680,10 @@ static int siw_init_rresp(struct siw_qp *qp, struct siw_rx_stream *srx)
        }
        spin_lock_irqsave(&qp->sq_lock, flags);
 
+       if (unlikely(!qp->attrs.irq_size)) {
+               run_sq = 0;
+               goto error_irq;
+       }
        if (tx_work->wr_status == SIW_WR_IDLE) {
                /*
                 * immediately schedule READ response w/o
@@ -712,8 +716,9 @@ static int siw_init_rresp(struct siw_qp *qp, struct siw_rx_stream *srx)
                /* RRESP now valid as current TX wqe or placed into IRQ */
                smp_store_mb(resp->flags, SIW_WQE_VALID);
        } else {
-               pr_warn("siw: [QP %u]: irq %d exceeded %d\n", qp_id(qp),
-                       qp->irq_put % qp->attrs.irq_size, qp->attrs.irq_size);
+error_irq:
+               pr_warn("siw: [QP %u]: IRQ exceeded or null, size %d\n",
+                       qp_id(qp), qp->attrs.irq_size);
 
                siw_init_terminate(qp, TERM_ERROR_LAYER_RDMAP,
                                   RDMAP_ETYPE_REMOTE_OPERATION,
@@ -740,6 +745,9 @@ static int siw_orqe_start_rx(struct siw_qp *qp)
        struct siw_sqe *orqe;
        struct siw_wqe *wqe = NULL;
 
+       if (unlikely(!qp->attrs.orq_size))
+               return -EPROTO;
+
        /* make sure ORQ indices are current */
        smp_mb();
 
@@ -796,8 +804,8 @@ int siw_proc_rresp(struct siw_qp *qp)
                 */
                rv = siw_orqe_start_rx(qp);
                if (rv) {
-                       pr_warn("siw: [QP %u]: ORQ empty at idx %d\n",
-                               qp_id(qp), qp->orq_get % qp->attrs.orq_size);
+                       pr_warn("siw: [QP %u]: ORQ empty, size %d\n",
+                               qp_id(qp), qp->attrs.orq_size);
                        goto error_term;
                }
                rv = siw_rresp_check_ntoh(srx, frx);
@@ -1290,11 +1298,13 @@ static int siw_rdmap_complete(struct siw_qp *qp, int error)
                                              wc_status);
                siw_wqe_put_mem(wqe, SIW_OP_READ);
 
-               if (!error)
+               if (!error) {
                        rv = siw_check_tx_fence(qp);
-               else
-                       /* Disable current ORQ eleement */
-                       WRITE_ONCE(orq_get_current(qp)->flags, 0);
+               } else {
+                       /* Disable current ORQ element */
+                       if (qp->attrs.orq_size)
+                               WRITE_ONCE(orq_get_current(qp)->flags, 0);
+               }
                break;
 
        case RDMAP_RDMA_READ_REQ:

diff --git a/drivers/infiniband/sw/siw/siw_qp_tx.c b/drivers/infiniband/sw/siw/siw_qp_tx.c
index d19d832..7989c40 100644 (file)
--- a/drivers/infiniband/sw/siw/siw_qp_tx.c
+++ b/drivers/infiniband/sw/siw/siw_qp_tx.c
@@ -1107,8 +1107,8 @@ next_wqe:
                /*
                 * RREQ may have already been completed by inbound RRESP!
                 */
-               if (tx_type == SIW_OP_READ ||
-                   tx_type == SIW_OP_READ_LOCAL_INV) {
+               if ((tx_type == SIW_OP_READ ||
+                    tx_type == SIW_OP_READ_LOCAL_INV) && qp->attrs.orq_size) {
                        /* Cleanup pending entry in ORQ */
                        qp->orq_put--;
                        qp->orq[qp->orq_put % qp->attrs.orq_size].flags = 0;

diff --git a/drivers/infiniband/sw/siw/siw_verbs.c b/drivers/infiniband/sw/siw/siw_verbs.c
index 68fd053..e389d44 100644 (file)
--- a/drivers/infiniband/sw/siw/siw_verbs.c
+++ b/drivers/infiniband/sw/siw/siw_verbs.c
@@ -365,13 +365,23 @@ struct ib_qp *siw_create_qp(struct ib_pd *pd,
        if (rv)
                goto err_out;
 
+       num_sqe = attrs->cap.max_send_wr;
+       num_rqe = attrs->cap.max_recv_wr;
+
        /* All queue indices are derived from modulo operations
         * on a free running 'get' (consumer) and 'put' (producer)
         * unsigned counter. Having queue sizes at power of two
         * avoids handling counter wrap around.
         */
-       num_sqe = roundup_pow_of_two(attrs->cap.max_send_wr);
-       num_rqe = roundup_pow_of_two(attrs->cap.max_recv_wr);
+       if (num_sqe)
+               num_sqe = roundup_pow_of_two(num_sqe);
+       else {
+               /* Zero sized SQ is not supported */
+               rv = -EINVAL;
+               goto err_out;
+       }
+       if (num_rqe)
+               num_rqe = roundup_pow_of_two(num_rqe);
 
        if (udata)
                qp->sendq = vmalloc_user(num_sqe * sizeof(struct siw_sqe));
@@ -379,7 +389,6 @@ struct ib_qp *siw_create_qp(struct ib_pd *pd,
                qp->sendq = vzalloc(num_sqe * sizeof(struct siw_sqe));
 
        if (qp->sendq == NULL) {
-               siw_dbg(base_dev, "SQ size %d alloc failed\n", num_sqe);
                rv = -ENOMEM;
                goto err_out_xa;
        }
@@ -413,7 +422,6 @@ struct ib_qp *siw_create_qp(struct ib_pd *pd,
                        qp->recvq = vzalloc(num_rqe * sizeof(struct siw_rqe));
 
                if (qp->recvq == NULL) {
-                       siw_dbg(base_dev, "RQ size %d alloc failed\n", num_rqe);
                        rv = -ENOMEM;
                        goto err_out_xa;
                }
@@ -966,9 +974,9 @@ int siw_post_receive(struct ib_qp *base_qp, const struct ib_recv_wr *wr,
        unsigned long flags;
        int rv = 0;
 
-       if (qp->srq) {
+       if (qp->srq || qp->attrs.rq_size == 0) {
                *bad_wr = wr;
-               return -EOPNOTSUPP; /* what else from errno.h? */
+               return -EINVAL;
        }
        if (!rdma_is_kernel_res(&qp->base_qp.res)) {
                siw_dbg_qp(qp, "no kernel post_recv for user mapped rq\n");