svcrdma: Combine list fields in struct svc_rdma_op_ctxt

Clean up: The free list and the dto_q list fields are never used at
the same time. Reduce the size of struct svc_rdma_op_ctxt by
combining these fields.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

3 files changed, 22 insertions, 28 deletions

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index f77a7bc1612c..b105f73e3ca2 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -70,7 +70,7 @@ extern atomic_t rdma_stat_sq_prod;
  * completes.
  */
 struct svc_rdma_op_ctxt {
-        struct list_head free;
+        struct list_head list;
         struct svc_rdma_op_ctxt *read_hdr;
         struct svc_rdma_fastreg_mr *frmr;
         int hdr_count;
@@ -78,7 +78,6 @@ struct svc_rdma_op_ctxt {
         struct ib_cqe cqe;
         struct ib_cqe reg_cqe;
         struct ib_cqe inv_cqe;
-        struct list_head dto_q;
         u32 byte_len;
         u32 position;
         struct svcxprt_rdma *xprt;
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 172b537f8cfc..b9ccd73631a9 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -608,18 +608,16 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 
         spin_lock_bh(&rdma_xprt->sc_rq_dto_lock);
         if (!list_empty(&rdma_xprt->sc_read_complete_q)) {
-                ctxt = list_entry(rdma_xprt->sc_read_complete_q.next,
-                                  struct svc_rdma_op_ctxt,
-                                  dto_q);
-                list_del_init(&ctxt->dto_q);
+                ctxt = list_first_entry(&rdma_xprt->sc_read_complete_q,
+                                        struct svc_rdma_op_ctxt, list);
+                list_del(&ctxt->list);
                 spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock);
                 rdma_read_complete(rqstp, ctxt);
                 goto complete;
         } else if (!list_empty(&rdma_xprt->sc_rq_dto_q)) {
-                ctxt = list_entry(rdma_xprt->sc_rq_dto_q.next,
-                                  struct svc_rdma_op_ctxt,
-                                  dto_q);
-                list_del_init(&ctxt->dto_q);
+                ctxt = list_first_entry(&rdma_xprt->sc_rq_dto_q,
+                                        struct svc_rdma_op_ctxt, list);
+                list_del(&ctxt->list);
         } else {
                 atomic_inc(&rdma_stat_rq_starve);
                 clear_bit(XPT_DATA, &xprt->xpt_flags);
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 023eaa01157f..87b8b5a10324 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -157,8 +157,7 @@ static struct svc_rdma_op_ctxt *alloc_ctxt(struct svcxprt_rdma *xprt,
         ctxt = kmalloc(sizeof(*ctxt), flags);
         if (ctxt) {
                 ctxt->xprt = xprt;
-                INIT_LIST_HEAD(&ctxt->free);
-                INIT_LIST_HEAD(&ctxt->dto_q);
+                INIT_LIST_HEAD(&ctxt->list);
         }
         return ctxt;
 }
@@ -180,7 +179,7 @@ static bool svc_rdma_prealloc_ctxts(struct svcxprt_rdma *xprt)
                         dprintk("svcrdma: No memory for RDMA ctxt\n");
                         return false;
                 }
-                list_add(&ctxt->free, &xprt->sc_ctxts);
+                list_add(&ctxt->list, &xprt->sc_ctxts);
         }
         return true;
 }
@@ -195,8 +194,8 @@ struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
                 goto out_empty;
 
         ctxt = list_first_entry(&xprt->sc_ctxts,
-                                struct svc_rdma_op_ctxt, free);
-        list_del_init(&ctxt->free);
+                                struct svc_rdma_op_ctxt, list);
+        list_del(&ctxt->list);
         spin_unlock_bh(&xprt->sc_ctxt_lock);
 
 out:
@@ -256,7 +255,7 @@ void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
 
         spin_lock_bh(&xprt->sc_ctxt_lock);
         xprt->sc_ctxt_used--;
-        list_add(&ctxt->free, &xprt->sc_ctxts);
+        list_add(&ctxt->list, &xprt->sc_ctxts);
         spin_unlock_bh(&xprt->sc_ctxt_lock);
 }
 
@@ -266,8 +265,8 @@ static void svc_rdma_destroy_ctxts(struct svcxprt_rdma *xprt)
                 struct svc_rdma_op_ctxt *ctxt;
 
                 ctxt = list_first_entry(&xprt->sc_ctxts,
-                                        struct svc_rdma_op_ctxt, free);
-                list_del(&ctxt->free);
+                                        struct svc_rdma_op_ctxt, list);
+                list_del(&ctxt->list);
                 kfree(ctxt);
         }
 }
@@ -404,7 +403,7 @@ static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc)
         /* All wc fields are now known to be valid */
         ctxt->byte_len = wc->byte_len;
         spin_lock(&xprt->sc_rq_dto_lock);
-        list_add_tail(&ctxt->dto_q, &xprt->sc_rq_dto_q);
+        list_add_tail(&ctxt->list, &xprt->sc_rq_dto_q);
         spin_unlock(&xprt->sc_rq_dto_lock);
 
         set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
@@ -525,7 +524,7 @@ void svc_rdma_wc_read(struct ib_cq *cq, struct ib_wc *wc)
 
                 read_hdr = ctxt->read_hdr;
                 spin_lock(&xprt->sc_rq_dto_lock);
-                list_add_tail(&read_hdr->dto_q,
+                list_add_tail(&read_hdr->list,
                               &xprt->sc_read_complete_q);
                 spin_unlock(&xprt->sc_rq_dto_lock);
 
@@ -1213,20 +1212,18 @@ static void __svc_rdma_free(struct work_struct *work)
          */
         while (!list_empty(&rdma->sc_read_complete_q)) {
                 struct svc_rdma_op_ctxt *ctxt;
-                ctxt = list_entry(rdma->sc_read_complete_q.next,
-                                  struct svc_rdma_op_ctxt,
-                                  dto_q);
-                list_del_init(&ctxt->dto_q);
+                ctxt = list_first_entry(&rdma->sc_read_complete_q,
+                                        struct svc_rdma_op_ctxt, list);
+                list_del(&ctxt->list);
                 svc_rdma_put_context(ctxt, 1);
         }
 
         /* Destroy queued, but not processed recv completions */
         while (!list_empty(&rdma->sc_rq_dto_q)) {
                 struct svc_rdma_op_ctxt *ctxt;
-                ctxt = list_entry(rdma->sc_rq_dto_q.next,
-                                  struct svc_rdma_op_ctxt,
-                                  dto_q);
-                list_del_init(&ctxt->dto_q);
+                ctxt = list_first_entry(&rdma->sc_rq_dto_q,
+                                        struct svc_rdma_op_ctxt, list);
+                list_del(&ctxt->list);
                 svc_rdma_put_context(ctxt, 1);
         }