From d247aabd391c3b2fa4f26874ed9136a7a142fcfd Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Sun, 9 Oct 2022 20:44:02 -0600
Subject: treewide: use get_random_u32_{above,below}() instead of manual loop

These cases were done with this Coccinelle:

@@
expression E;
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (I > E);
+   I = get_random_u32_below(E + 1);

@@
expression E;
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (I >= E);
+   I = get_random_u32_below(E);

@@
expression E;
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (I < E);
+   I = get_random_u32_above(E - 1);

@@
expression E;
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (I <= E);
+   I = get_random_u32_above(E);

@@
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (!I);
+   I = get_random_u32_above(0);

@@
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (I == 0);
+   I = get_random_u32_above(0);

@@
expression E;
@@
- E + 1 + get_random_u32_below(U32_MAX - E)
+ get_random_u32_above(E)

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 fs/ext4/mmp.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

(limited to 'fs/ext4/mmp.c')

diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index 588cb09c5291..4681fff6665f 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -262,13 +262,7 @@ void ext4_stop_mmpd(struct ext4_sb_info *sbi)
  */
 static unsigned int mmp_new_seq(void)
 {
-	u32 new_seq;
-
-	do {
-		new_seq = get_random_u32();
-	} while (new_seq > EXT4_MMP_SEQ_MAX);
-
-	return new_seq;
+	return get_random_u32_below(EXT4_MMP_SEQ_MAX + 1);
 }
 
 /*
-- 
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