The use of "all" was originally RCU specific - I'd pushed it down to
being used for any CPU lists -- then Yuri suggested pushing it down
further to be used by any bitmap, which is done here.
As a trivial one line extension, we also accept the inverse "none"
as a valid alias.
Cc: Yury Norov <yury.no...@gmail.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: "Paul E. McKenney" <paul...@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortma...@windriver.com>
---
Documentation/admin-guide/kernel-parameters.rst | 11 +++++++++++
lib/bitmap.c | 9 +++++++++
2 files changed, 20 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.rst
b/Documentation/admin-guide/kernel-parameters.rst
index 682ab28b5c94..5e080080b058 100644
--- a/Documentation/admin-guide/kernel-parameters.rst
+++ b/Documentation/admin-guide/kernel-parameters.rst
@@ -68,7 +68,18 @@ For example one can add to the command line following
parameter:
where the final item represents CPUs 100,101,125,126,150,151,...
+The following convenience aliases are also accepted and used:
+ foo_cpus=all
+
+will provide an full/all-set cpu mask for the associated boot argument.
+
+ foo_cpus=none
+
+will provide an empty/cleared cpu mask for the associated boot argument.
+
+Note that "all" and "none" are not necessarily valid/sensible input values
+for each available boot parameter expecting a CPU list.
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
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 75006c4036e9..a1010646fbe5 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -627,6 +627,7 @@ static const char *bitmap_parse_region(const char *str,
struct region *r)
* 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
+ * Optionally the self-descriptive "all" or "none" can be used.
*
* Returns: 0 on success, -errno on invalid input strings. Error values:
*
@@ -640,8 +641,16 @@ int bitmap_parselist(const char *buf, unsigned long
*maskp, int nmaskbits)
struct region r;
long ret;
+ if (!strcmp(buf, "all")) {
+ bitmap_fill(maskp, nmaskbits);
+ return 0;
+ }
+
bitmap_zero(maskp, nmaskbits);
+ if (!strcmp(buf, "none"))
+ return 0;
+
while (buf) {
buf = bitmap_find_region(buf);
if (buf == NULL)
--
2.17.1
