Merge tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:

 - Support for "N" as alias for last bit in bitmap parsing library (eg
   using syntax like "nohz_full=2-N")

 - kvfree_rcu updates

 - mm_dump_obj() updates. (One of these is to mm, but was suggested by
   Andrew Morton.)

 - RCU callback offloading update

 - Polling RCU grace-period interfaces

 - Realtime-related RCU updates

 - Tasks-RCU updates

 - Torture-test updates

 - Torture-test scripting updates

 - Miscellaneous fixes

* tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits)
  rcutorture: Test start_poll_synchronize_rcu() and poll_state_synchronize_rcu()
  rcu: Provide polling interfaces for Tiny RCU grace periods
  torture: Fix kvm.sh --datestamp regex check
  torture: Consolidate qemu-cmd duration editing into kvm-transform.sh
  torture: Print proper vmlinux path for kvm-again.sh runs
  torture: Make TORTURE_TRUST_MAKE available in kvm-again.sh environment
  torture: Make kvm-transform.sh update jitter commands
  torture: Add --duration argument to kvm-again.sh
  torture: Add kvm-again.sh to rerun a previous torture-test
  torture: Create a "batches" file for build reuse
  torture: De-capitalize TORTURE_SUITE
  torture: Make upper-case-only no-dot no-slash scenario names official
  torture: Rename SRCU-t and SRCU-u to avoid lowercase characters
  torture: Remove no-mpstat error message
  torture: Record kvm-test-1-run.sh and kvm-test-1-run-qemu.sh PIDs
  torture: Record jitter start/stop commands
  torture: Extract kvm-test-1-run-qemu.sh from kvm-test-1-run.sh
  torture: Record TORTURE_KCONFIG_GDB_ARG in qemu-cmd
  torture: Abstract jitter.sh start/stop into scripts
  rcu: Provide polling interfaces for Tree RCU grace periods
  ...

2 files changed, 69 insertions, 26 deletions

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 75006c4036e9..9f4626a4c95f 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -487,30 +487,25 @@ EXPORT_SYMBOL(bitmap_print_to_pagebuf);
 
 /*
  * Region 9-38:4/10 describes the following bitmap structure:
- * 0	   9  12    18			38
- * .........****......****......****......
- *	    ^  ^     ^			 ^
- *      start  off   group_len	       end
+ * 0	   9  12    18			38	     N
+ * .........****......****......****..................
+ *	    ^  ^     ^			 ^	     ^
+ *      start  off   group_len	       end	 nbits
  */
 struct region {
 	unsigned int start;
 	unsigned int off;
 	unsigned int group_len;
 	unsigned int end;
+	unsigned int nbits;
 };
 
-static int bitmap_set_region(const struct region *r,
-				unsigned long *bitmap, int nbits)
+static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
 {
 	unsigned int start;
 
-	if (r->end >= nbits)
-		return -ERANGE;
-
 	for (start = r->start; start <= r->end; start += r->group_len)
 		bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
-
-	return 0;
 }
 
 static int bitmap_check_region(const struct region *r)
@@ -518,14 +513,23 @@ static int bitmap_check_region(const struct region *r)
 	if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
 		return -EINVAL;
 
+	if (r->end >= r->nbits)
+		return -ERANGE;
+
 	return 0;
 }
 
-static const char *bitmap_getnum(const char *str, unsigned int *num)
+static const char *bitmap_getnum(const char *str, unsigned int *num,
+				 unsigned int lastbit)
 {
 	unsigned long long n;
 	unsigned int len;
 
+	if (str[0] == 'N') {
+		*num = lastbit;
+		return str + 1;
+	}
+
 	len = _parse_integer(str, 10, &n);
 	if (!len)
 		return ERR_PTR(-EINVAL);
@@ -573,7 +577,9 @@ static const char *bitmap_find_region_reverse(const char *start, const char *end
 
 static const char *bitmap_parse_region(const char *str, struct region *r)
 {
-	str = bitmap_getnum(str, &r->start);
+	unsigned int lastbit = r->nbits - 1;
+
+	str = bitmap_getnum(str, &r->start, lastbit);
 	if (IS_ERR(str))
 		return str;
 
@@ -583,7 +589,7 @@ static const char *bitmap_parse_region(const char *str, struct region *r)
 	if (*str != '-')
 		return ERR_PTR(-EINVAL);
 
-	str = bitmap_getnum(str + 1, &r->end);
+	str = bitmap_getnum(str + 1, &r->end, lastbit);
 	if (IS_ERR(str))
 		return str;
 
@@ -593,14 +599,14 @@ static const char *bitmap_parse_region(const char *str, struct region *r)
 	if (*str != ':')
 		return ERR_PTR(-EINVAL);
 
-	str = bitmap_getnum(str + 1, &r->off);
+	str = bitmap_getnum(str + 1, &r->off, lastbit);
 	if (IS_ERR(str))
 		return str;
 
 	if (*str != '/')
 		return ERR_PTR(-EINVAL);
 
-	return bitmap_getnum(str + 1, &r->group_len);
+	return bitmap_getnum(str + 1, &r->group_len, lastbit);
 
 no_end:
 	r->end = r->start;
@@ -627,6 +633,10 @@ no_pattern:
  * From each group will be used only defined amount of bits.
  * Syntax: range:used_size/group_size
  * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
+ * The value 'N' can be used as a dynamically substituted token for the
+ * maximum allowed value; i.e (nmaskbits - 1).  Keep in mind that it is
+ * dynamic, so if system changes cause the bitmap width to change, such
+ * as more cores in a CPU list, then any ranges using N will also change.
  *
  * Returns: 0 on success, -errno on invalid input strings. Error values:
  *
@@ -640,7 +650,8 @@ int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
 	struct region r;
 	long ret;
 
-	bitmap_zero(maskp, nmaskbits);
+	r.nbits = nmaskbits;
+	bitmap_zero(maskp, r.nbits);
 
 	while (buf) {
 		buf = bitmap_find_region(buf);
@@ -655,9 +666,7 @@ int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
 		if (ret)
 			return ret;
 
-		ret = bitmap_set_region(&r, maskp, nmaskbits);
-		if (ret)
-			return ret;
+		bitmap_set_region(&r, maskp);
 	}
 
 	return 0;
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 0ea0e8258f14..9cd575583180 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -34,6 +34,8 @@ static const unsigned long exp1[] __initconst = {
 	BITMAP_FROM_U64(0x3333333311111111ULL),
 	BITMAP_FROM_U64(0xffffffff77777777ULL),
 	BITMAP_FROM_U64(0),
+	BITMAP_FROM_U64(0x00008000),
+	BITMAP_FROM_U64(0x80000000),
 };
 
 static const unsigned long exp2[] __initconst = {
@@ -334,15 +336,47 @@ static const struct test_bitmap_parselist parselist_tests[] __initconst = {
 	{0, " ,  ,,  , ,   ",		&exp1[12 * step], 8, 0},
 	{0, " ,  ,,  , ,   \n",		&exp1[12 * step], 8, 0},
 
+	{0, "0-0",			&exp1[0], 32, 0},
+	{0, "1-1",			&exp1[1 * step], 32, 0},
+	{0, "15-15",			&exp1[13 * step], 32, 0},
+	{0, "31-31",			&exp1[14 * step], 32, 0},
+
+	{0, "0-0:0/1",			&exp1[12 * step], 32, 0},
+	{0, "0-0:1/1",			&exp1[0], 32, 0},
+	{0, "0-0:1/31",			&exp1[0], 32, 0},
+	{0, "0-0:31/31",		&exp1[0], 32, 0},
+	{0, "1-1:1/1",			&exp1[1 * step], 32, 0},
+	{0, "0-15:16/31",		&exp1[2 * step], 32, 0},
+	{0, "15-15:1/2",		&exp1[13 * step], 32, 0},
+	{0, "15-15:31/31",		&exp1[13 * step], 32, 0},
+	{0, "15-31:1/31",		&exp1[13 * step], 32, 0},
+	{0, "16-31:16/31",		&exp1[3 * step], 32, 0},
+	{0, "31-31:31/31",		&exp1[14 * step], 32, 0},
+
+	{0, "N-N",			&exp1[14 * step], 32, 0},
+	{0, "0-0:1/N",			&exp1[0], 32, 0},
+	{0, "0-0:N/N",			&exp1[0], 32, 0},
+	{0, "0-15:16/N",		&exp1[2 * step], 32, 0},
+	{0, "15-15:N/N",		&exp1[13 * step], 32, 0},
+	{0, "15-N:1/N",			&exp1[13 * step], 32, 0},
+	{0, "16-N:16/N",		&exp1[3 * step], 32, 0},
+	{0, "N-N:N/N",			&exp1[14 * step], 32, 0},
+
+	{0, "0-N:1/3,1-N:1/3,2-N:1/3",		&exp1[8 * step], 32, 0},
+	{0, "0-31:1/3,1-31:1/3,2-31:1/3",	&exp1[8 * step], 32, 0},
+	{0, "1-10:8/12,8-31:24/29,0-31:0/3",	&exp1[9 * step], 32, 0},
+
 	{-EINVAL, "-1",	NULL, 8, 0},
 	{-EINVAL, "-0",	NULL, 8, 0},
 	{-EINVAL, "10-1", NULL, 8, 0},
-	{-EINVAL, "0-31:", NULL, 8, 0},
-	{-EINVAL, "0-31:0", NULL, 8, 0},
-	{-EINVAL, "0-31:0/", NULL, 8, 0},
-	{-EINVAL, "0-31:0/0", NULL, 8, 0},
-	{-EINVAL, "0-31:1/0", NULL, 8, 0},
-	{-EINVAL, "0-31:10/1", NULL, 8, 0},
+	{-ERANGE, "8-8", NULL, 8, 0},
+	{-ERANGE, "0-31", NULL, 8, 0},
+	{-EINVAL, "0-31:", NULL, 32, 0},
+	{-EINVAL, "0-31:0", NULL, 32, 0},
+	{-EINVAL, "0-31:0/", NULL, 32, 0},
+	{-EINVAL, "0-31:0/0", NULL, 32, 0},
+	{-EINVAL, "0-31:1/0", NULL, 32, 0},
+	{-EINVAL, "0-31:10/1", NULL, 32, 0},
 	{-EOVERFLOW, "0-98765432123456789:10/1", NULL, 8, 0},
 
 	{-EINVAL, "a-31", NULL, 8, 0},