The patch titled
Subject: bitmap_parse: support 'all' semantics
has been added to the -mm tree. Its filename is
bitmap_parse-support-all-semantics.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/bitmap_parse-support-all-semantics.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/bitmap_parse-support-all-semantics.patch
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------------------------------------------------------
From: Yury Norov <yury.norov@xxxxxxxxx>
Subject: bitmap_parse: support 'all' semantics
RCU code supports an 'all' group as a special case when parsing rcu_nocbs
parameter. This patch moves the 'all' support to the core bitmap_parse
code, so that all bitmap users can enjoy this extension.
Moving 'all' parsing to a bitmap_parse level, also allows users to pass
patterns together with 'all' in regular group:pattern format
Link: https://lkml.kernel.org/r/20210421031326.72816-2-yury.norov@xxxxxxxxx
Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.rst | 5 +++++
lib/bitmap.c | 9 +++++++++
lib/test_bitmap.c | 7 +++++++
3 files changed, 21 insertions(+)
--- a/Documentation/admin-guide/kernel-parameters.rst~bitmap_parse-support-all-semantics
+++ a/Documentation/admin-guide/kernel-parameters.rst
@@ -76,6 +76,11 @@ to change, such as less cores in the CPU
will also change. Use the same on a small 4 core system, and "16-N" becomes
"16-3" and now the same boot input will be flagged as invalid (start > end).
+The special case-tolerant group name "all" has a meaning of selecting all CPUs,
+such that "isolcpus=all" is the equivalent of "isolcpus=0-N".
+
+The semantics of "N" and "all" is supported on a level of bitmaps and holds for
+all users of bitmap_parse().
This document may not be entirely up to date and comprehensive. The command
"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
--- a/lib/bitmap.c~bitmap_parse-support-all-semantics
+++ a/lib/bitmap.c
@@ -581,6 +581,14 @@ static const char *bitmap_parse_region(c
{
unsigned int lastbit = r->nbits - 1;
+ if (!strncasecmp(str, "all", 3)) {
+ r->start = 0;
+ r->end = lastbit;
+ str += 3;
+
+ goto check_pattern;
+ }
+
str = bitmap_getnum(str, &r->start, lastbit);
if (IS_ERR(str))
return str;
@@ -595,6 +603,7 @@ static const char *bitmap_parse_region(c
if (IS_ERR(str))
return str;
+check_pattern:
if (end_of_region(*str))
goto no_pattern;
--- a/lib/test_bitmap.c~bitmap_parse-support-all-semantics
+++ a/lib/test_bitmap.c
@@ -366,6 +366,13 @@ static const struct test_bitmap_parselis
{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},
+ {0, "all", &exp1[8 * step], 32, 0},
+ {0, "0, 1, all, ", &exp1[8 * step], 32, 0},
+ {0, "all:1/2", &exp1[4 * step], 32, 0},
+ {0, "ALL:1/2", &exp1[4 * step], 32, 0},
+ {-EINVAL, "al", NULL, 8, 0},
+ {-EINVAL, "alll", NULL, 8, 0},
+
{-EINVAL, "-1", NULL, 8, 0},
{-EINVAL, "-0", NULL, 8, 0},
{-EINVAL, "10-1", NULL, 8, 0},
_
Patches currently in -mm which might be from yury.norov@xxxxxxxxx are
bitmap_parse-support-all-semantics.patch
rcu-tree_plugin-dont-handle-the-case-of-all-cpu-range.patch
