RDS: make m_rdma_op a member of rds_message

This eliminates a separate memory alloc, although
it is now necessary to add an "r_active" flag, since
it is no longer to use the m_rdma_op pointer as an
indicator of if an rdma op is present.

rdma SGs allocated from rm sg pool.

rds_rm_size also gets bigger. It's a little inefficient to
run through CMSGs twice, but it makes later steps a lot smoother.

Signed-off-by: Andy Grover <andy.grover@oracle.com>

1 files changed, 60 insertions, 53 deletions

diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index a21edad33950..7ff3379bab14 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -458,26 +458,60 @@ void rds_rdma_free_op(struct rds_rdma_op *ro)
         }
 
         kfree(ro->r_notifier);
-        kfree(ro);
+        ro->r_notifier = NULL;
+        ro->r_active = 0;
+}
+
+/*
+ * Count the number of pages needed to describe an incoming iovec.
+ */
+static int rds_rdma_pages(struct rds_rdma_args *args)
+{
+        struct rds_iovec vec;
+        struct rds_iovec __user *local_vec;
+        unsigned int tot_pages = 0;
+        unsigned int nr_pages;
+        unsigned int i;
+
+        local_vec = (struct rds_iovec __user *)(unsigned long) args->local_vec_addr;
+
+        /* figure out the number of pages in the vector */
+        for (i = 0; i < args->nr_local; i++) {
+                if (copy_from_user(&vec, &local_vec[i],
+                                   sizeof(struct rds_iovec)))
+                        return -EFAULT;
+
+                nr_pages = rds_pages_in_vec(&vec);
+                if (nr_pages == 0)
+                        return -EINVAL;
+
+                tot_pages += nr_pages;
+        }
+
+        return tot_pages;
+}
+
+int rds_rdma_extra_size(struct rds_rdma_args *args)
+{
+        return rds_rdma_pages(args) * sizeof(struct scatterlist);
 }
 
 /*
  * args is a pointer to an in-kernel copy in the sendmsg cmsg.
  */
-static struct rds_rdma_op *rds_rdma_prepare(struct rds_sock *rs,
-                                            struct rds_rdma_args *args)
+static int rds_rdma_prepare(struct rds_message *rm,
+                            struct rds_sock *rs,
+                            struct rds_rdma_args *args)
 {
         struct rds_iovec vec;
-        struct rds_rdma_op *op = NULL;
+        struct rds_rdma_op *op = &rm->rdma.m_rdma_op;
         unsigned int nr_pages;
-        unsigned int max_pages;
         unsigned int nr_bytes;
         struct page **pages = NULL;
         struct rds_iovec __user *local_vec;
-        struct scatterlist *sg;
         unsigned int nr;
         unsigned int i, j;
-        int ret;
+        int ret = 0;
 
 
         if (rs->rs_bound_addr == 0) {
@@ -490,44 +524,21 @@ static struct rds_rdma_op *rds_rdma_prepare(struct rds_sock *rs,
                 goto out;
         }
 
-        nr_pages = 0;
-        max_pages = 0;
-
-        local_vec = (struct rds_iovec __user *)(unsigned long) args->local_vec_addr;
-
-        /* figure out the number of pages in the vector */
-        for (i = 0; i < args->nr_local; i++) {
-                if (copy_from_user(&vec, &local_vec[i],
-                                   sizeof(struct rds_iovec))) {
-                        ret = -EFAULT;
-                        goto out;
-                }
-
-                nr = rds_pages_in_vec(&vec);
-                if (nr == 0) {
-                        ret = -EINVAL;
-                        goto out;
-                }
-
-                max_pages = max(nr, max_pages);
-                nr_pages += nr;
-        }
-
-        pages = kcalloc(max_pages, sizeof(struct page *), GFP_KERNEL);
-        if (!pages) {
-                ret = -ENOMEM;
+        nr_pages = rds_rdma_pages(args);
+        if (nr_pages < 0)
                 goto out;
-        }
 
-        op = kzalloc(offsetof(struct rds_rdma_op, r_sg[nr_pages]), GFP_KERNEL);
-        if (!op) {
+        pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
+        if (!pages) {
                 ret = -ENOMEM;
                 goto out;
         }
 
+        op->r_sg = rds_message_alloc_sgs(rm, nr_pages);
         op->r_write = !!(args->flags & RDS_RDMA_READWRITE);
         op->r_fence = !!(args->flags & RDS_RDMA_FENCE);
         op->r_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME);
+        op->r_active = 1;
         op->r_recverr = rs->rs_recverr;
         WARN_ON(!nr_pages);
         sg_init_table(op->r_sg, nr_pages);
@@ -564,6 +575,8 @@ static struct rds_rdma_op *rds_rdma_prepare(struct rds_sock *rs,
                (unsigned long long)args->remote_vec.addr,
                op->r_key);
 
+        local_vec = (struct rds_iovec __user *)(unsigned long) args->local_vec_addr;
+
         for (i = 0; i < args->nr_local; i++) {
                 if (copy_from_user(&vec, &local_vec[i],
                                    sizeof(struct rds_iovec))) {
@@ -580,11 +593,6 @@ static struct rds_rdma_op *rds_rdma_prepare(struct rds_sock *rs,
                 rs->rs_user_addr = vec.addr;
                 rs->rs_user_bytes = vec.bytes;
 
-                /* did the user change the vec under us? */
-                if (nr > max_pages || op->r_nents + nr > nr_pages) {
-                        ret = -EINVAL;
-                        goto out;
-                }
                 /* If it's a WRITE operation, we want to pin the pages for reading.
                  * If it's a READ operation, we need to pin the pages for writing.
                  */
@@ -599,6 +607,7 @@ static struct rds_rdma_op *rds_rdma_prepare(struct rds_sock *rs,
 
                 for (j = 0; j < nr; j++) {
                         unsigned int offset = vec.addr & ~PAGE_MASK;
+                        struct scatterlist *sg;
 
                         sg = &op->r_sg[op->r_nents + j];
                         sg_set_page(sg, pages[j],
@@ -628,12 +637,10 @@ static struct rds_rdma_op *rds_rdma_prepare(struct rds_sock *rs,
         ret = 0;
 out:
         kfree(pages);
-        if (ret) {
-                if (op)
-                        rds_rdma_free_op(op);
-                op = ERR_PTR(ret);
-        }
-        return op;
+        if (ret)
+                rds_rdma_free_op(op);
+
+        return ret;
 }
 
 /*
@@ -643,17 +650,17 @@ out:
 int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
                           struct cmsghdr *cmsg)
 {
-        struct rds_rdma_op *op;
+        int ret;
 
         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_rdma_args)) ||
-            rm->rdma.m_rdma_op)
+            rm->rdma.m_rdma_op.r_active)
                 return -EINVAL;
 
-        op = rds_rdma_prepare(rs, CMSG_DATA(cmsg));
-        if (IS_ERR(op))
-                return PTR_ERR(op);
+        ret = rds_rdma_prepare(rm, rs, CMSG_DATA(cmsg));
+        if (ret)
+                return ret;
+
         rds_stats_inc(s_send_rdma);
-        rm->rdma.m_rdma_op = op;
         return 0;
 }