File bsc-1206791-05-prandom_u32_max.patch of Package drbd

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File bsc-1206791-05-prandom_u32_max.patch of Package drbd

by heming.zhao@suse.com on 20220105 (bsc#1206791)

This is SUSE special patch, and this patch cocci codes were partly
copied from upstream kernel commit 81895a65ec63ee1daec3255dc1a06675d2fbe915
("treewide: use prandom_u32_max() when possible, part 1").

Because I don't know cocci syntax, so in drbd_state.c this patch
directly modifies prandom_u32() to prandom_u32_max(U32_MAX). All
other cases use cocci to modify.

---
by heming.zhao@suse.com on 20230311 (bsc#1209168)

OpenSUSE kernel had been updated to v6.2.1, modification on 20220105
is not suitable. The upstream commit 8032bf1233a7 ("treewide:
use get_random_u32_below() instead of deprecated function") replaced
the prandom.h function prandom_u32_max with the random.h function
get_random_u32_below.

I changed this patch under latest kernel, using get_random_u32_below
to replace prandom_u32_max.

---

diff -Nupr a/drbd/drbd-kernel-compat/cocci/prandom_u32__no_present.cocci b/drbd/drbd-kernel-compat/cocci/prandom_u32__no_present.cocci
--- a/drbd/drbd-kernel-compat/cocci/prandom_u32__no_present.cocci	2023-01-04 23:15:30.435899748 +0800
+++ b/drbd/drbd-kernel-compat/cocci/prandom_u32__no_present.cocci	2023-01-05 08:58:23.177198823 +0800
@@ -1,3 +1,76 @@
-@@ @@
-- prandom_u32()
-+ random32()
+@basic@
+expression E;
+type T;
+identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
+typedef u64;
+@@
+(
+- ((T)get_random_u32() % (E))
++ get_random_u32_below(E)
+|
+- ((T)get_random_u32() & ((E) - 1))
++ get_random_u32_below(E * XXX_MAKE_SURE_E_IS_POW2)
+|
+- ((u64)(E) * get_random_u32() >> 32)
++ get_random_u32_below(E)
+|
+- ((T)get_random_u32() & ~PAGE_MASK)
++ get_random_u32_below(PAGE_SIZE)
+)
+
+@multi_line@
+identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
+identifier RAND;
+expression E;
+@@
+
+-       RAND = get_random_u32();
+        ... when != RAND
+-       RAND %= (E);
++       RAND = get_random_u32_below(E);
+
+// Find a potential literal
+@literal_mask@
+expression LITERAL;
+type T;
+identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
+position p;
+@@
+
+        ((T)get_random_u32()@p & (LITERAL))
+
+// Add one to the literal.
+@script:python add_one@
+literal << literal_mask.LITERAL;
+RESULT;
+@@
+
+value = None
+if literal.startswith('0x'):
+        value = int(literal, 16)
+elif literal[0] in '123456789':
+        value = int(literal, 10)
+if value is None:
+        print("I don't know how to handle %s" % (literal))
+        cocci.include_match(False)
+elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
+        print("Skipping 0x%x for cleanup elsewhere" % (value))
+        cocci.include_match(False)
+elif value & (value + 1) != 0:
+        print("Skipping 0x%x because it's not a power of two minus one" % (value))
+        cocci.include_match(False)
+elif literal.startswith('0x'):
+        coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
+else:
+        coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))
+
+// Replace the literal mask with the calculated result.
+@plus_one@
+expression literal_mask.LITERAL;
+position literal_mask.p;
+expression add_one.RESULT;
+identifier FUNC;
+@@
+
+-       (FUNC()@p & (LITERAL))
++       get_random_u32_below(RESULT)
diff -Nupr a/drbd/drbd_state.c b/drbd/drbd_state.c
--- a/drbd/drbd_state.c	2023-01-05 09:00:01.252434773 +0800
+++ b/drbd/drbd_state.c	2023-01-05 09:02:47.519078927 +0800
@@ -4488,7 +4488,7 @@ change_cluster_wide_state(bool (*change)
 	}
 
 	do
-		reply->tid = prandom_u32();
+		reply->tid = get_random_u32_below(U32_MAX);
 	while (!reply->tid);
 
 	request.tid = cpu_to_be32(reply->tid);
@@ -4716,7 +4716,7 @@ retry:
 	*reply = (struct twopc_reply) { 0 };
 
 	do
-		reply->tid = prandom_u32();
+		reply->tid = get_random_u32_below(U32_MAX);
 	while (!reply->tid);
 
 	request.tid = cpu_to_be32(reply->tid);

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File bsc-1206791-05-prandom_u32_max.patch of Package drbd

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