NFSv4: Convert nfs_alloc_seqid() to return an ERR_PTR() if allocation fails

When we relax the sequencing on the NFSv4.1 OPEN/CLOSE code, we will want
to use the value NULL to indicate that no sequencing is needed.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4proc.c

@@ -988,7 +988,7 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 		goto err_free_p;
 
 	p->o_arg.seqid = nfs_alloc_seqid(&sp->so_seqid, gfp_mask);
-	if (p->o_arg.seqid == NULL)
+	if (IS_ERR(p->o_arg.seqid))
 		goto err_free_label;
 	nfs_sb_active(dentry->d_sb);
 	p->dentry = dget(dentry);
@@ -2779,7 +2779,7 @@ int nfs4_do_close(struct nfs4_state *state, gfp_t gfp_mask, int wait)
 	calldata->arg.fh = NFS_FH(state->inode);
 	/* Serialization for the sequence id */
 	calldata->arg.seqid = nfs_alloc_seqid(&state->owner->so_seqid, gfp_mask);
-	if (calldata->arg.seqid == NULL)
+	if (IS_ERR(calldata->arg.seqid))
 		goto out_free_calldata;
 	calldata->arg.fmode = 0;
 	calldata->arg.bitmask = server->cache_consistency_bitmask;
@@ -5517,7 +5517,7 @@ static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *
 		goto out;
 	seqid = nfs_alloc_seqid(&lsp->ls_seqid, GFP_KERNEL);
 	status = -ENOMEM;
-	if (seqid == NULL)
+	if (IS_ERR(seqid))
 		goto out;
 	task = nfs4_do_unlck(request, nfs_file_open_context(request->fl_file), lsp, seqid);
 	status = PTR_ERR(task);
@@ -5558,10 +5558,10 @@ static struct nfs4_lockdata *nfs4_alloc_lockdata(struct file_lock *fl,
 	p->arg.fh = NFS_FH(inode);
 	p->arg.fl = &p->fl;
 	p->arg.open_seqid = nfs_alloc_seqid(&lsp->ls_state->owner->so_seqid, gfp_mask);
-	if (p->arg.open_seqid == NULL)
+	if (IS_ERR(p->arg.open_seqid))
 		goto out_free;
 	p->arg.lock_seqid = nfs_alloc_seqid(&lsp->ls_seqid, gfp_mask);
-	if (p->arg.lock_seqid == NULL)
+	if (IS_ERR(p->arg.lock_seqid))
 		goto out_free_seqid;
 	p->arg.lock_stateid = &lsp->ls_stateid;
 	p->arg.lock_owner.clientid = server->nfs_client->cl_clientid;

fs/nfs/nfs4state.c

@@ -1003,11 +1003,11 @@ struct nfs_seqid *nfs_alloc_seqid(struct nfs_seqid_counter *counter, gfp_t gfp_m
 	struct nfs_seqid *new;
 
 	new = kmalloc(sizeof(*new), gfp_mask);
-	if (new != NULL) {
+	if (new == NULL)
+		return ERR_PTR(-ENOMEM);
 	new->sequence = counter;
 	INIT_LIST_HEAD(&new->list);
 	new->task = NULL;
-	}
 	return new;
 }