[PATCH v2] staging: lustre: llite: Fix variable length array warning

[Guru Das Srinagesh]

Fix sparse warning "warning: Variable length array is used." by using
kmalloc_array to allocate the required amount of memory instead and
kfree to deallocate memory after use.

Signed-off-by: Guru Das Srinagesh <gurooo...@gmail.com>
---
 v2:
   - Added missing check for NULL return value of kmalloc_array()

 drivers/staging/lustre/lustre/llite/xattr.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/lustre/lustre/llite/xattr.c 
b/drivers/staging/lustre/lustre/llite/xattr.c
index 6187bff..880eee9 100644
--- a/drivers/staging/lustre/lustre/llite/xattr.c
+++ b/drivers/staging/lustre/lustre/llite/xattr.c
@@ -86,13 +86,17 @@ ll_xattr_set_common(const struct xattr_handler *handler,
                    const char *name, const void *value, size_t size,
                    int flags)
 {
-       char fullname[strlen(handler->prefix) + strlen(name) + 1];
+       int fullname_len = strlen(handler->prefix) + strlen(name) + 1;
+       char *fullname = kmalloc_array(fullname_len, sizeof(char), GFP_KERNEL);
        struct ll_sb_info *sbi = ll_i2sbi(inode);
        struct ptlrpc_request *req = NULL;
        const char *pv = value;
        __u64 valid;
        int rc;
 
+       if (fullname == NULL)
+               return -ENOMEM;
+
        if (flags == XATTR_REPLACE) {
                ll_stats_ops_tally(ll_i2sbi(inode), LPROC_LL_REMOVEXATTR, 1);
                valid = OBD_MD_FLXATTRRM;
@@ -153,6 +157,9 @@ ll_xattr_set_common(const struct xattr_handler *handler,
        }
 
        ptlrpc_req_finished(req);
+
+       kfree(fullname);
+
        return 0;
 }
 
@@ -363,13 +370,17 @@ static int ll_xattr_get_common(const struct xattr_handler 
*handler,
                               struct dentry *dentry, struct inode *inode,
                               const char *name, void *buffer, size_t size)
 {
-       char fullname[strlen(handler->prefix) + strlen(name) + 1];
+       int fullname_len = strlen(handler->prefix) + strlen(name) + 1;
+       char *fullname = kmalloc_array(fullname_len, sizeof(char), GFP_KERNEL);
        struct ll_sb_info *sbi = ll_i2sbi(inode);
 #ifdef CONFIG_FS_POSIX_ACL
        struct ll_inode_info *lli = ll_i2info(inode);
 #endif
        int rc;
 
+       if (fullname == NULL)
+               return -ENOMEM;
+
        CDEBUG(D_VFSTRACE, "VFS Op:inode="DFID"(%p)\n",
               PFID(ll_inode2fid(inode)), inode);
 
@@ -411,8 +422,12 @@ static int ll_xattr_get_common(const struct xattr_handler 
*handler,
                return -ENODATA;
 #endif
        sprintf(fullname, "%s%s\n", handler->prefix, name);
-       return ll_xattr_list(inode, fullname, handler->flags, buffer, size,
-                            OBD_MD_FLXATTR);
+
+       rc = ll_xattr_list(inode, fullname, handler->flags, buffer, size,
+                          OBD_MD_FLXATTR);
+       kfree(fullname);
+
+       return rc;
 }
 
 static ssize_t ll_getxattr_lov(struct inode *inode, void *buf, size_t buf_size)
-- 
2.7.4