xprtrdma: Stack relief in fmr_op_map()

fmr_op_map() declares a 64 element array of u64 in automatic
storage. This is 512 bytes (8 * 64) on the stack.

Instead, when FMR memory registration is in use, pre-allocate a
physaddr array for each rpcrdma_mw.

This is a pre-requisite for increasing the r/wsize maximum for
FMR on platforms with 4KB pages.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Devesh Sharma <devesh.sharma@avagotech.com>
Tested-By: Devesh Sharma <devesh.sharma@avagotech.com>
Reviewed-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/net/sunrpc/xprtrdma/fmr_ops.c b/net/sunrpc/xprtrdma/fmr_ops.c
index 52f9ad5fe19bb1e06c06c482a0afc80a146701e4..4a53ad5ab4b36722e5597888985987b60edf6cc9 100644 (file)
--- a/net/sunrpc/xprtrdma/fmr_ops.c
+++ b/net/sunrpc/xprtrdma/fmr_ops.c
@@ -72,13 +72,19 @@ fmr_op_init(struct rpcrdma_xprt *r_xprt)
        i = (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS;
        dprintk("RPC:       %s: initializing %d FMRs\n", __func__, i);
 
+       rc = -ENOMEM;
        while (i--) {
                r = kzalloc(sizeof(*r), GFP_KERNEL);
                if (!r)
-                       return -ENOMEM;
+                       goto out;
+
+               r->r.fmr.physaddrs = kmalloc(RPCRDMA_MAX_FMR_SGES *
+                                            sizeof(u64), GFP_KERNEL);
+               if (!r->r.fmr.physaddrs)
+                       goto out_free;
 
-               r->r.fmr = ib_alloc_fmr(pd, mr_access_flags, &fmr_attr);
-               if (IS_ERR(r->r.fmr))
+               r->r.fmr.fmr = ib_alloc_fmr(pd, mr_access_flags, &fmr_attr);
+               if (IS_ERR(r->r.fmr.fmr))
                        goto out_fmr_err;
 
                list_add(&r->mw_list, &buf->rb_mws);
@@ -87,9 +93,12 @@ fmr_op_init(struct rpcrdma_xprt *r_xprt)
        return 0;
 
 out_fmr_err:
-       rc = PTR_ERR(r->r.fmr);
+       rc = PTR_ERR(r->r.fmr.fmr);
        dprintk("RPC:       %s: ib_alloc_fmr status %i\n", __func__, rc);
+       kfree(r->r.fmr.physaddrs);
+out_free:
        kfree(r);
+out:
        return rc;
 }
 
@@ -98,7 +107,7 @@ __fmr_unmap(struct rpcrdma_mw *r)
 {
        LIST_HEAD(l);
 
-       list_add(&r->r.fmr->list, &l);
+       list_add(&r->r.fmr.fmr->list, &l);
        return ib_unmap_fmr(&l);
 }
 
@@ -113,7 +122,6 @@ fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
        struct ib_device *device = ia->ri_device;
        enum dma_data_direction direction = rpcrdma_data_dir(writing);
        struct rpcrdma_mr_seg *seg1 = seg;
-       u64 physaddrs[RPCRDMA_MAX_DATA_SEGS];
        int len, pageoff, i, rc;
        struct rpcrdma_mw *mw;
 
@@ -138,7 +146,7 @@ fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
                nsegs = RPCRDMA_MAX_FMR_SGES;
        for (i = 0; i < nsegs;) {
                rpcrdma_map_one(device, seg, direction);
-               physaddrs[i] = seg->mr_dma;
+               mw->r.fmr.physaddrs[i] = seg->mr_dma;
                len += seg->mr_len;
                ++seg;
                ++i;
@@ -148,12 +156,13 @@ fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
                        break;
        }
 
-       rc = ib_map_phys_fmr(mw->r.fmr, physaddrs, i, seg1->mr_dma);
+       rc = ib_map_phys_fmr(mw->r.fmr.fmr, mw->r.fmr.physaddrs,
+                            i, seg1->mr_dma);
        if (rc)
                goto out_maperr;
 
        seg1->rl_mw = mw;
-       seg1->mr_rkey = mw->r.fmr->rkey;
+       seg1->mr_rkey = mw->r.fmr.fmr->rkey;
        seg1->mr_base = seg1->mr_dma + pageoff;
        seg1->mr_nsegs = i;
        seg1->mr_len = len;
@@ -207,10 +216,13 @@ fmr_op_destroy(struct rpcrdma_buffer *buf)
        while (!list_empty(&buf->rb_all)) {
                r = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all);
                list_del(&r->mw_all);
-               rc = ib_dealloc_fmr(r->r.fmr);
+               kfree(r->r.fmr.physaddrs);
+
+               rc = ib_dealloc_fmr(r->r.fmr.fmr);
                if (rc)
                        dprintk("RPC:       %s: ib_dealloc_fmr failed %i\n",
                                __func__, rc);
+
                kfree(r);
        }
 }

diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index df92884400c48338e47f8cf484f069b627c67c7b..110d685b4ac5f11e7c7fd7a153662b2d469a9f7f 100644 (file)
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -206,9 +206,14 @@ struct rpcrdma_frmr {
        struct rpcrdma_xprt             *fr_xprt;
 };
 
+struct rpcrdma_fmr {
+       struct ib_fmr           *fmr;
+       u64                     *physaddrs;
+};
+
 struct rpcrdma_mw {
        union {
-               struct ib_fmr           *fmr;
+               struct rpcrdma_fmr      fmr;
                struct rpcrdma_frmr     frmr;
        } r;
        void                    (*mw_sendcompletion)(struct ib_wc *);