[PATCH 2/2] vsprintf: remove redundant and unused %pCn format specifier

Luca Ceresoli
2025-03-07T11:19:30Z

%pC and %pCn print the same string, and commit 900cca294425 ("lib/vsprintf:
add %pC{,n,r} format specifiers for clocks") introducing them does not
clarify any intended difference. It can be assumed %pC is a default for
%pCn as some other specifiers do, but not all are consistent with this
policy. Moreover there is now no other suffix other than 'n', which makes a
default not really useful.

All users in the kernel were using %pC except for one which has been
converted. So now remove %pCn and all the unnecessary extra code and
documentation.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
Documentation/core-api/printk-formats.rst | 3 +--
lib/vsprintf.c | 10 ++--------
2 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index ecccc0473da9c10f45f2464566f690472c61401e..f3009e6ec80a864c330c8812efcd82c12f4066b3 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -571,9 +571,8 @@ struct clk
::

%pC pll1
- %pCn pll1

-For printing struct clk structures. %pC and %pCn print the name of the clock
+For printing struct clk structures. %pC prints the name of the clock
(Common Clock Framework) or a unique 32-bit ID (legacy clock framework).

Passed by reference.
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 56fe96319292674c9f79559cf78dd0d99d1a1f06..143d55cb1c12acac21a6c6bafd255437e878f280 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1969,15 +1969,11 @@ char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
if (check_pointer(&buf, end, clk, spec))
return buf;

- switch (fmt[1]) {
- case 'n':
- default:
#ifdef CONFIG_COMMON_CLK
- return string(buf, end, __clk_get_name(clk), spec);
+ return string(buf, end, __clk_get_name(clk), spec);
#else
- return ptr_to_id(buf, end, clk, spec);
+ return ptr_to_id(buf, end, clk, spec);
#endif
- }
}

static
@@ -2382,8 +2378,6 @@ char *rust_fmt_argument(char *buf, char *end, void *ptr);
* T time64_t
* - 'C' For a clock, it prints the name (Common Clock Framework) or address
* (legacy clock framework) of the clock
- * - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
- * (legacy clock framework) of the clock
* - 'G' For flags to be printed as a collection of symbolic strings that would
* construct the specific value. Supported flags given by option:
* p page flags (see struct page) given as pointer to unsigned long

--
2.48.1