svcrdma: Scrub BUG_ON() and WARN_ON() call sites

Current convention is to avoid using BUG_ON() in places where an
oops could cause complete system failure.

Replace BUG_ON() call sites in svcrdma with an assertion error
message and allow execution to continue safely.

Some BUG_ON() calls are removed because they have never fired in
production (that we are aware of).

Some WARN_ON() calls are also replaced where a back trace is not
helpful; e.g., in a workqueue task.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index b3b7bb8..577f865 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -95,14 +95,6 @@ static void rdma_build_arg_xdr(struct svc_rqst *rqstp,
        rqstp->rq_respages = &rqstp->rq_pages[sge_no];
        rqstp->rq_next_page = rqstp->rq_respages + 1;
 
-       /* We should never run out of SGE because the limit is defined to
-        * support the max allowed RPC data length
-        */
-       BUG_ON(bc && (sge_no == ctxt->count));
-       BUG_ON((rqstp->rq_arg.head[0].iov_len + rqstp->rq_arg.page_len)
-              != byte_count);
-       BUG_ON(rqstp->rq_arg.len != byte_count);
-
        /* If not all pages were used from the SGL, free the remaining ones */
        bc = sge_no;
        while (sge_no < ctxt->count) {
@@ -477,8 +469,6 @@ static int rdma_read_complete(struct svc_rqst *rqstp,
        int page_no;
        int ret;
 
-       BUG_ON(!head);
-
        /* Copy RPC pages */
        for (page_no = 0; page_no < head->count; page_no++) {
                put_page(rqstp->rq_pages[page_no]);
@@ -567,7 +557,6 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
        }
        dprintk("svcrdma: processing ctxt=%p on xprt=%p, rqstp=%p, status=%d\n",
                ctxt, rdma_xprt, rqstp, ctxt->wc_status);
-       BUG_ON(ctxt->wc_status != IB_WC_SUCCESS);
        atomic_inc(&rdma_stat_recv);
 
        /* Build up the XDR from the receive buffers. */

diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 9f1b506..7d79897 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -60,8 +60,11 @@ static int map_xdr(struct svcxprt_rdma *xprt,
        u32 page_off;
        int page_no;
 
-       BUG_ON(xdr->len !=
-              (xdr->head[0].iov_len + xdr->page_len + xdr->tail[0].iov_len));
+       if (xdr->len !=
+           (xdr->head[0].iov_len + xdr->page_len + xdr->tail[0].iov_len)) {
+               pr_err("svcrdma: map_xdr: XDR buffer length error\n");
+               return -EIO;
+       }
 
        /* Skip the first sge, this is for the RPCRDMA header */
        sge_no = 1;
@@ -150,7 +153,11 @@ static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
        int bc;
        struct svc_rdma_op_ctxt *ctxt;
 
-       BUG_ON(vec->count > RPCSVC_MAXPAGES);
+       if (vec->count > RPCSVC_MAXPAGES) {
+               pr_err("svcrdma: Too many pages (%lu)\n", vec->count);
+               return -EIO;
+       }
+
        dprintk("svcrdma: RDMA_WRITE rmr=%x, to=%llx, xdr_off=%d, "
                "write_len=%d, vec->sge=%p, vec->count=%lu\n",
                rmr, (unsigned long long)to, xdr_off,
@@ -190,7 +197,10 @@ static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
                sge_off = 0;
                sge_no++;
                xdr_sge_no++;
-               BUG_ON(xdr_sge_no > vec->count);
+               if (xdr_sge_no > vec->count) {
+                       pr_err("svcrdma: Too many sges (%d)\n", xdr_sge_no);
+                       goto err;
+               }
                bc -= sge_bytes;
                if (sge_no == xprt->sc_max_sge)
                        break;
@@ -421,7 +431,10 @@ static int send_reply(struct svcxprt_rdma *rdma,
                ctxt->sge[sge_no].lkey = rdma->sc_dma_lkey;
                ctxt->sge[sge_no].length = sge_bytes;
        }
-       BUG_ON(byte_count != 0);
+       if (byte_count != 0) {
+               pr_err("svcrdma: Could not map %d bytes\n", byte_count);
+               goto err;
+       }
 
        /* Save all respages in the ctxt and remove them from the
         * respages array. They are our pages until the I/O
@@ -442,7 +455,10 @@ static int send_reply(struct svcxprt_rdma *rdma,
        }
        rqstp->rq_next_page = rqstp->rq_respages + 1;
 
-       BUG_ON(sge_no > rdma->sc_max_sge);
+       if (sge_no > rdma->sc_max_sge) {
+               pr_err("svcrdma: Too many sges (%d)\n", sge_no);
+               goto err;
+       }
        memset(&send_wr, 0, sizeof send_wr);
        ctxt->wr_op = IB_WR_SEND;
        send_wr.wr_id = (unsigned long)ctxt;

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 4ba11d0..f2e059b 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -139,7 +139,6 @@ void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
        struct svcxprt_rdma *xprt;
        int i;
 
-       BUG_ON(!ctxt);
        xprt = ctxt->xprt;
        if (free_pages)
                for (i = 0; i < ctxt->count; i++)
@@ -339,12 +338,14 @@ static void process_context(struct svcxprt_rdma *xprt,
 
        switch (ctxt->wr_op) {
        case IB_WR_SEND:
-               BUG_ON(ctxt->frmr);
+               if (ctxt->frmr)
+                       pr_err("svcrdma: SEND: ctxt->frmr != NULL\n");
                svc_rdma_put_context(ctxt, 1);
                break;
 
        case IB_WR_RDMA_WRITE:
-               BUG_ON(ctxt->frmr);
+               if (ctxt->frmr)
+                       pr_err("svcrdma: WRITE: ctxt->frmr != NULL\n");
                svc_rdma_put_context(ctxt, 0);
                break;
 
@@ -353,19 +354,21 @@ static void process_context(struct svcxprt_rdma *xprt,
                svc_rdma_put_frmr(xprt, ctxt->frmr);
                if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
                        struct svc_rdma_op_ctxt *read_hdr = ctxt->read_hdr;
-                       BUG_ON(!read_hdr);
-                       spin_lock_bh(&xprt->sc_rq_dto_lock);
-                       set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
-                       list_add_tail(&read_hdr->dto_q,
-                                     &xprt->sc_read_complete_q);
-                       spin_unlock_bh(&xprt->sc_rq_dto_lock);
+                       if (read_hdr) {
+                               spin_lock_bh(&xprt->sc_rq_dto_lock);
+                               set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
+                               list_add_tail(&read_hdr->dto_q,
+                                             &xprt->sc_read_complete_q);
+                               spin_unlock_bh(&xprt->sc_rq_dto_lock);
+                       } else {
+                               pr_err("svcrdma: ctxt->read_hdr == NULL\n");
+                       }
                        svc_xprt_enqueue(&xprt->sc_xprt);
                }
                svc_rdma_put_context(ctxt, 0);
                break;
 
        default:
-               BUG_ON(1);
                printk(KERN_ERR "svcrdma: unexpected completion type, "
                       "opcode=%d\n",
                       ctxt->wr_op);
@@ -513,7 +516,10 @@ int svc_rdma_post_recv(struct svcxprt_rdma *xprt)
        buflen = 0;
        ctxt->direction = DMA_FROM_DEVICE;
        for (sge_no = 0; buflen < xprt->sc_max_req_size; sge_no++) {
-               BUG_ON(sge_no >= xprt->sc_max_sge);
+               if (sge_no >= xprt->sc_max_sge) {
+                       pr_err("svcrdma: Too many sges (%d)\n", sge_no);
+                       goto err_put_ctxt;
+               }
                page = svc_rdma_get_page();
                ctxt->pages[sge_no] = page;
                pa = ib_dma_map_page(xprt->sc_cm_id->device,
@@ -820,7 +826,7 @@ void svc_rdma_put_frmr(struct svcxprt_rdma *rdma,
        if (frmr) {
                frmr_unmap_dma(rdma, frmr);
                spin_lock_bh(&rdma->sc_frmr_q_lock);
-               BUG_ON(!list_empty(&frmr->frmr_list));
+               WARN_ON_ONCE(!list_empty(&frmr->frmr_list));
                list_add(&frmr->frmr_list, &rdma->sc_frmr_q);
                spin_unlock_bh(&rdma->sc_frmr_q_lock);
        }
@@ -1123,7 +1129,9 @@ static void __svc_rdma_free(struct work_struct *work)
        dprintk("svcrdma: svc_rdma_free(%p)\n", rdma);
 
        /* We should only be called from kref_put */
-       BUG_ON(atomic_read(&rdma->sc_xprt.xpt_ref.refcount) != 0);
+       if (atomic_read(&rdma->sc_xprt.xpt_ref.refcount) != 0)
+               pr_err("svcrdma: sc_xprt still in use? (%d)\n",
+                      atomic_read(&rdma->sc_xprt.xpt_ref.refcount));
 
        /*
         * Destroy queued, but not processed read completions. Note
@@ -1151,8 +1159,12 @@ static void __svc_rdma_free(struct work_struct *work)
        }
 
        /* Warn if we leaked a resource or under-referenced */
-       WARN_ON(atomic_read(&rdma->sc_ctxt_used) != 0);
-       WARN_ON(atomic_read(&rdma->sc_dma_used) != 0);
+       if (atomic_read(&rdma->sc_ctxt_used) != 0)
+               pr_err("svcrdma: ctxt still in use? (%d)\n",
+                      atomic_read(&rdma->sc_ctxt_used));
+       if (atomic_read(&rdma->sc_dma_used) != 0)
+               pr_err("svcrdma: dma still in use? (%d)\n",
+                      atomic_read(&rdma->sc_dma_used));
 
        /* De-allocate fastreg mr */
        rdma_dealloc_frmr_q(rdma);
@@ -1252,7 +1264,6 @@ int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
        if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
                return -ENOTCONN;
 
-       BUG_ON(wr->send_flags != IB_SEND_SIGNALED);
        wr_count = 1;
        for (n_wr = wr->next; n_wr; n_wr = n_wr->next)
                wr_count++;