[lustre-devel] [PATCH 01/10] lustre: ldlm: discard varname in ldlm_pool.

[James Simmons]

From: NeilBrown <neilb at suse.com>

This allocated buffer serves no purpose.
A constant string is copied into it, it is passed to some
function which copies it out again, then the buffer is freed.
Instead, we can pass the constant string to that function.

Signed-off-by: NeilBrown <neilb at suse.com>
WC-bug-id: https://jira.whamcloud.com/browse/LU-4423
Reviewed-on: https://review.whamcloud.com/35273
Reviewed-by: Andreas Dilger <adilger at whamcloud.com>
Reviewed-by: Petros Koutoupis <pkoutoupis at cray.com>
Signed-off-by: James Simmons <jsimmons at infradead.org>
---
 fs/lustre/ldlm/ldlm_internal.h |  2 --
 fs/lustre/ldlm/ldlm_pool.c     | 18 +++++-------------
 2 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/fs/lustre/ldlm/ldlm_internal.h b/fs/lustre/ldlm/ldlm_internal.h
index 05d5b08..a6dee9f 100644
--- a/fs/lustre/ldlm/ldlm_internal.h
+++ b/fs/lustre/ldlm/ldlm_internal.h
@@ -31,8 +31,6 @@
  * Lustre is a trademark of Sun Microsystems, Inc.
  */
 
-#define MAX_STRING_SIZE 128
-
 extern int ldlm_srv_namespace_nr;
 extern int ldlm_cli_namespace_nr;
 extern struct mutex ldlm_srv_namespace_lock;
diff --git a/fs/lustre/ldlm/ldlm_pool.c b/fs/lustre/ldlm/ldlm_pool.c
index 6714c30..3dfbde5 100644
--- a/fs/lustre/ldlm/ldlm_pool.c
+++ b/fs/lustre/ldlm/ldlm_pool.c
@@ -504,9 +504,9 @@ static ssize_t grant_speed_show(struct kobject *kobj, struct attribute *attr,
 LDLM_POOL_SYSFS_WRITER_NOLOCK_STORE(lock_volume_factor, atomic);
 LUSTRE_RW_ATTR(lock_volume_factor);
 
-#define LDLM_POOL_ADD_VAR(name, var, ops)			\
+#define LDLM_POOL_ADD_VAR(_name, var, ops)			\
 	do {							\
-		snprintf(var_name, MAX_STRING_SIZE, #name);	\
+		pool_vars[0].name = #_name;			\
 		pool_vars[0].data = var;			\
 		pool_vars[0].fops = ops;			\
 		ldebugfs_add_vars(pl->pl_debugfs_entry, pool_vars, NULL);\
@@ -558,25 +558,18 @@ static int ldlm_pool_debugfs_init(struct ldlm_pool *pl)
 						 ns_pool);
 	struct dentry *debugfs_ns_parent;
 	struct lprocfs_vars pool_vars[2];
-	char *var_name = NULL;
 	int rc = 0;
 
-	var_name = kzalloc(MAX_STRING_SIZE + 1, GFP_NOFS);
-	if (!var_name)
-		return -ENOMEM;
-
 	debugfs_ns_parent = ns->ns_debugfs_entry;
 	if (IS_ERR_OR_NULL(debugfs_ns_parent)) {
 		CERROR("%s: debugfs entry is not initialized\n",
 		       ldlm_ns_name(ns));
 		rc = -EINVAL;
-		goto out_free_name;
+		goto out;
 	}
 	pl->pl_debugfs_entry = debugfs_create_dir("pool", debugfs_ns_parent);
 
-	var_name[MAX_STRING_SIZE] = '\0';
 	memset(pool_vars, 0, sizeof(pool_vars));
-	pool_vars[0].name = var_name;
 
 	LDLM_POOL_ADD_VAR(state, pl, &lprocfs_pool_state_fops);
 
@@ -584,7 +577,7 @@ static int ldlm_pool_debugfs_init(struct ldlm_pool *pl)
 					   LDLM_POOL_FIRST_STAT, 0);
 	if (!pl->pl_stats) {
 		rc = -ENOMEM;
-		goto out_free_name;
+		goto out;
 	}
 
 	lprocfs_counter_init(pl->pl_stats, LDLM_POOL_GRANTED_STAT,
@@ -623,8 +616,7 @@ static int ldlm_pool_debugfs_init(struct ldlm_pool *pl)
 	debugfs_create_file("stats", 0644, pl->pl_debugfs_entry, pl->pl_stats,
 			    &lprocfs_stats_seq_fops);
 
-out_free_name:
-	kfree(var_name);
+out:
 	return rc;
 }
 
-- 
1.8.3.1