[PATCH v4 05/10] smb/client: sort smb2_error_map_table array

[chenxiaosong.chenxiaosong@linux.dev]

From: ChenXiaoSong <chenxiaosong@kylinos.cn>

Sort the array in ascending order, and then we can use binary search
algorithm to quickly find the target status code.

Since the smb2_init_maperror() is called only once when the module is
loaded, the array is sorted just once.

Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
---
 fs/smb/client/cifsfs.c       |  2 ++
 fs/smb/client/smb2maperror.c | 25 ++++++++++++++++++++++++-
 fs/smb/client/smb2proto.h    |  1 +
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index 6eccb9ed9daa..77d14b3dd650 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -49,6 +49,7 @@
 #endif
 #include "fs_context.h"
 #include "cached_dir.h"
+#include "smb2proto.h"
 
 /*
  * DOS dates from 1980/1/1 through 2107/12/31
@@ -1908,6 +1909,7 @@ static int __init
 init_cifs(void)
 {
 	int rc = 0;
+	smb2_init_maperror();
 	cifs_proc_init();
 	INIT_LIST_HEAD(&cifs_tcp_ses_list);
 /*
diff --git a/fs/smb/client/smb2maperror.c b/fs/smb/client/smb2maperror.c
index a77467d2d81c..1bd4196386dd 100644
--- a/fs/smb/client/smb2maperror.c
+++ b/fs/smb/client/smb2maperror.c
@@ -8,6 +8,7 @@
  *
  */
 #include <linux/errno.h>
+#include <linux/sort.h>
 #include "cifsglob.h"
 #include "cifs_debug.h"
 #include "smb2pdu.h"
@@ -22,7 +23,7 @@ struct status_to_posix_error {
 	char *status_string;
 };
 
-static const struct status_to_posix_error smb2_error_map_table[] = {
+static struct status_to_posix_error smb2_error_map_table[] = {
 	{STATUS_WAIT_1, -EIO, "STATUS_WAIT_1"},
 	{STATUS_WAIT_2, -EIO, "STATUS_WAIT_2"},
 	{STATUS_WAIT_3, -EIO, "STATUS_WAIT_3"},
@@ -2418,6 +2419,20 @@ static const struct status_to_posix_error smb2_error_map_table[] = {
 	"STATUS_SMB_NO_PREAUTH_INTEGRITY_HASH_OVERLAP"},
 };
 
+static unsigned int err_map_num = sizeof(smb2_error_map_table) /
+				     sizeof(struct status_to_posix_error);
+
+static int cmp_smb2_status(const void *_a, const void *_b)
+{
+	const struct status_to_posix_error *a = _a, *b = _b;
+
+	if (a->smb2_status < b->smb2_status)
+		return -1;
+	if (a->smb2_status > b->smb2_status)
+		return 1;
+	return 0;
+}
+
 int
 map_smb2_to_linux_error(char *buf, bool log_err)
 {
@@ -2461,3 +2476,11 @@ map_smb2_to_linux_error(char *buf, bool log_err)
 			   le32_to_cpu(smb2err), rc);
 	return rc;
 }
+
+void smb2_init_maperror(void)
+{
+	/* Sort in ascending order */
+	sort(smb2_error_map_table, err_map_num,
+	     sizeof(struct status_to_posix_error),
+	     cmp_smb2_status, NULL);
+}
diff --git a/fs/smb/client/smb2proto.h b/fs/smb/client/smb2proto.h
index 5241daaae543..c988f6b37a1b 100644
--- a/fs/smb/client/smb2proto.h
+++ b/fs/smb/client/smb2proto.h
@@ -21,6 +21,7 @@ struct smb_rqst;
  *****************************************************************
  */
 extern int map_smb2_to_linux_error(char *buf, bool log_err);
+extern void smb2_init_maperror(void);
 extern int smb2_check_message(char *buf, unsigned int length,
 			      struct TCP_Server_Info *server);
 extern unsigned int smb2_calc_size(void *buf);
-- 
2.43.0