NFS: create common routine for waiting for direct I/O to complete

We're about to add asynchrony to the NFS direct write path.  Begin by
abstracting out the common pieces in the read path.

The first piece is nfs_direct_read_wait, which works the same whether the
process is waiting for a read or a write.

Test plan:
Compile kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 26 insertions, 31 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 094456c3df9..2593f47eaff 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -159,6 +159,30 @@ static void nfs_direct_req_release(struct kref *kref)
 }
 
 /*
+ * Collects and returns the final error value/byte-count.
+ */
+static ssize_t nfs_direct_wait(struct nfs_direct_req *dreq)
+{
+        int result = -EIOCBQUEUED;
+
+        /* Async requests don't wait here */
+        if (dreq->iocb)
+                goto out;
+
+        result = wait_event_interruptible(dreq->wait,
+                                        (atomic_read(&dreq->complete) == 0));
+
+        if (!result)
+                result = atomic_read(&dreq->error);
+        if (!result)
+                result = atomic_read(&dreq->count);
+
+out:
+        kref_put(&dreq->kref, nfs_direct_req_release);
+        return (ssize_t) result;
+}
+
+/*
  * Note we also set the number of requests we have in the dreq when we are
  * done.  This prevents races with I/O completion so we will always wait
  * until all requests have been dispatched and completed.
@@ -213,7 +237,7 @@ static struct nfs_direct_req *nfs_direct_read_alloc(size_t nbytes, size_t rsize)
 /*
  * We must hold a reference to all the pages in this direct read request
  * until the RPCs complete.  This could be long *after* we are woken up in
- * nfs_direct_read_wait (for instance, if someone hits ^C on a slow server).
+ * nfs_direct_wait (for instance, if someone hits ^C on a slow server).
  *
  * In addition, synchronous I/O uses a stack-allocated iocb.  Thus we
  * can't trust the iocb is still valid here if this is a synchronous
@@ -315,35 +339,6 @@ static void nfs_direct_read_schedule(struct nfs_direct_req *dreq, unsigned long
         } while (count != 0);
 }
 
-/*
- * Collects and returns the final error value/byte-count.
- */
-static ssize_t nfs_direct_read_wait(struct nfs_direct_req *dreq, int intr)
-{
-        int result = -EIOCBQUEUED;
-
-        /* Async requests don't wait here */
-        if (dreq->iocb)
-                goto out;
-
-        result = 0;
-        if (intr) {
-                result = wait_event_interruptible(dreq->wait,
-                                        (atomic_read(&dreq->complete) == 0));
-        } else {
-                wait_event(dreq->wait, (atomic_read(&dreq->complete) == 0));
-        }
-
-        if (!result)
-                result = atomic_read(&dreq->error);
-        if (!result)
-                result = atomic_read(&dreq->count);
-
-out:
-        kref_put(&dreq->kref, nfs_direct_req_release);
-        return (ssize_t) result;
-}
-
 static ssize_t nfs_direct_read(struct kiocb *iocb, unsigned long user_addr, size_t count, loff_t file_offset, struct page **pages, unsigned int nr_pages)
 {
         ssize_t result;
@@ -366,7 +361,7 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, unsigned long user_addr, size
         nfs_add_stats(inode, NFSIOS_DIRECTREADBYTES, count);
         rpc_clnt_sigmask(clnt, &oldset);
         nfs_direct_read_schedule(dreq, user_addr, count, file_offset);
-        result = nfs_direct_read_wait(dreq, clnt->cl_intr);
+        result = nfs_direct_wait(dreq);
         rpc_clnt_sigunmask(clnt, &oldset);
 
         return result;