[PATCH v1 04/12] xprtrdma: Remove last ib_reg_phys_mr() call site

Chuck Lever
2015-07-09T20:42:18Z

All HCA providers have an ib_get_dma_mr() verb. Thus
rpcrdma_ia_open() will either grab the device's local_dma_key if one
is available, or it will call ib_get_dma_mr() which is a 100%
guaranteed fallback. There is never any need to use the
ib_reg_phys_mr() code path in rpcrdma_register_internal(), so it can
be removed.

The remaining logic in rpcrdma_{de}register_internal() is folded
into rpcrdma_{alloc,free}_regbuf().

Signed-off-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---
net/sunrpc/xprtrdma/verbs.c | 102 ++++++++-------------------------------
net/sunrpc/xprtrdma/xprt_rdma.h | 1
2 files changed, 21 insertions(+), 82 deletions(-)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 891c4ed..cdf5220 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -1229,75 +1229,6 @@ rpcrdma_mapping_error(struct rpcrdma_mr_seg *seg)
(unsigned long long)seg->mr_dma, seg->mr_dmalen);
}

-static int
-rpcrdma_register_internal(struct rpcrdma_ia *ia, void *va, int len,
- struct ib_mr **mrp, struct ib_sge *iov)
-{
- struct ib_phys_buf ipb;
- struct ib_mr *mr;
- int rc;
-
- /*
- * All memory passed here was kmalloc'ed, therefore phys-contiguous.
- */
- iov->addr = ib_dma_map_single(ia->ri_device,
- va, len, DMA_BIDIRECTIONAL);
- if (ib_dma_mapping_error(ia->ri_device, iov->addr))
- return -ENOMEM;
-
- iov->length = len;
-
- if (ia->ri_have_dma_lkey) {
- *mrp = NULL;
- iov->lkey = ia->ri_dma_lkey;
- return 0;
- } else if (ia->ri_bind_mem != NULL) {
- *mrp = NULL;
- iov->lkey = ia->ri_bind_mem->lkey;
- return 0;
- }
-
- ipb.addr = iov->addr;
- ipb.size = iov->length;
- mr = ib_reg_phys_mr(ia->ri_pd, &ipb, 1,
- IB_ACCESS_LOCAL_WRITE, &iov->addr);
-
- dprintk("RPC: %s: phys convert: 0x%llx "
- "registered 0x%llx length %d\n",
- __func__, (unsigned long long)ipb.addr,
- (unsigned long long)iov->addr, len);
-
- if (IS_ERR(mr)) {
- *mrp = NULL;
- rc = PTR_ERR(mr);
- dprintk("RPC: %s: failed with %i\n", __func__, rc);
- } else {
- *mrp = mr;
- iov->lkey = mr->lkey;
- rc = 0;
- }
-
- return rc;
-}
-
-static int
-rpcrdma_deregister_internal(struct rpcrdma_ia *ia,
- struct ib_mr *mr, struct ib_sge *iov)
-{
- int rc;
-
- ib_dma_unmap_single(ia->ri_device,
- iov->addr, iov->length, DMA_BIDIRECTIONAL);
-
- if (NULL == mr)
- return 0;
-
- rc = ib_dereg_mr(mr);
- if (rc)
- dprintk("RPC: %s: ib_dereg_mr failed %i\n", __func__, rc);
- return rc;
-}
-
/**
* rpcrdma_alloc_regbuf - kmalloc and register memory for SEND/RECV buffers
* @ia: controlling rpcrdma_ia
@@ -1317,26 +1248,30 @@ struct rpcrdma_regbuf *
rpcrdma_alloc_regbuf(struct rpcrdma_ia *ia, size_t size, gfp_t flags)
{
struct rpcrdma_regbuf *rb;
- int rc;
+ struct ib_sge *iov;

- rc = -ENOMEM;
rb = kmalloc(sizeof(*rb) + size, flags);
if (rb == NULL)
goto out;

- rb->rg_size = size;
- rb->rg_owner = NULL;
- rc = rpcrdma_register_internal(ia, rb->rg_base, size,
- &rb->rg_mr, &rb->rg_iov);
- if (rc)
+ iov = &rb->rg_iov;
+ iov->addr = ib_dma_map_single(ia->ri_device,
+ (void *)rb->rg_base, size,
+ DMA_BIDIRECTIONAL);
+ if (ib_dma_mapping_error(ia->ri_device, iov->addr))
goto out_free;

+ iov->length = size;
+ iov->lkey = ia->ri_have_dma_lkey ?
+ ia->ri_dma_lkey : ia->ri_bind_mem->lkey;
+ rb->rg_size = size;
+ rb->rg_owner = NULL;
return rb;

out_free:
kfree(rb);
out:
- return ERR_PTR(rc);
+ return ERR_PTR(-ENOMEM);
}

/**
@@ -1347,10 +1282,15 @@ out:
void
rpcrdma_free_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
{
- if (rb) {
- rpcrdma_deregister_internal(ia, rb->rg_mr, &rb->rg_iov);
- kfree(rb);
- }
+ struct ib_sge *iov;
+
+ if (!rb)
+ return;
+
+ iov = &rb->rg_iov;
+ ib_dma_unmap_single(ia->ri_device,
+ iov->addr, iov->length, DMA_BIDIRECTIONAL);
+ kfree(rb);
}

/*
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index abee472..ce4e79e 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -119,7 +119,6 @@ struct rpcrdma_ep {
struct rpcrdma_regbuf {
size_t rg_size;
struct rpcrdma_req *rg_owner;
- struct ib_mr *rg_mr;
struct ib_sge rg_iov;
__be32 rg_base[0] __attribute__ ((aligned(256)));
};