NFS: Convert nfs_get_lock_context to return an ERR_PTR on failure

We want to be able to distinguish between allocation failures, and
the case where the lock context is not needed (because there are no
locks).

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

1 files changed, 12 insertions, 4 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 1ba385b7c90d..22130df16218 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -450,6 +450,7 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,
         ssize_t result = -ENOMEM;
         struct inode *inode = iocb->ki_filp->f_mapping->host;
         struct nfs_direct_req *dreq;
+        struct nfs_lock_context *l_ctx;
 
         dreq = nfs_direct_req_alloc();
         if (dreq == NULL)
@@ -457,9 +458,12 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,
 
         dreq->inode = inode;
         dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
-        dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
-        if (dreq->l_ctx == NULL)
+        l_ctx = nfs_get_lock_context(dreq->ctx);
+        if (IS_ERR(l_ctx)) {
+                result = PTR_ERR(l_ctx);
                 goto out_release;
+        }
+        dreq->l_ctx = l_ctx;
         if (!is_sync_kiocb(iocb))
                 dreq->iocb = iocb;
 
@@ -849,6 +853,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
         ssize_t result = -ENOMEM;
         struct inode *inode = iocb->ki_filp->f_mapping->host;
         struct nfs_direct_req *dreq;
+        struct nfs_lock_context *l_ctx;
 
         dreq = nfs_direct_req_alloc();
         if (!dreq)
@@ -856,9 +861,12 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
 
         dreq->inode = inode;
         dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
-        dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
-        if (dreq->l_ctx == NULL)
+        l_ctx = nfs_get_lock_context(dreq->ctx);
+        if (IS_ERR(l_ctx)) {
+                result = PTR_ERR(l_ctx);
                 goto out_release;
+        }
+        dreq->l_ctx = l_ctx;
         if (!is_sync_kiocb(iocb))
                 dreq->iocb = iocb;