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Subject[PATCH 4.9 016/101] lib/vsprintf: Remove atomic-unsafe support for %pCr
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Geert Uytterhoeven <geert+renesas@glider.be>

commit 666902e42fd8344b923c02dc5b0f37948ff4f225 upstream.

"%pCr" formats the current rate of a clock, and calls clk_get_rate().
The latter obtains a mutex, hence it must not be called from atomic
context.

Remove support for this rarely-used format, as vsprintf() (and e.g.
printk()) must be callable from any context.

Any remaining out-of-tree users will start seeing the clock's name
printed instead of its rate.

Reported-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Fixes: 900cca2944254edd ("lib/vsprintf: add %pC{,n,r} format specifiers for clocks")
Link: http://lkml.kernel.org/r/1527845302-12159-5-git-send-email-geert+renesas@glider.be
To: Jia-Ju Bai <baijiaju1990@gmail.com>
To: Jonathan Corbet <corbet@lwn.net>
To: Michael Turquette <mturquette@baylibre.com>
To: Stephen Boyd <sboyd@kernel.org>
To: Zhang Rui <rui.zhang@intel.com>
To: Eduardo Valentin <edubezval@gmail.com>
To: Eric Anholt <eric@anholt.net>
To: Stefan Wahren <stefan.wahren@i2se.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-clk@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: stable@vger.kernel.org # 4.1+
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
Documentation/printk-formats.txt | 3 +--
lib/vsprintf.c | 3 ---
2 files changed, 1 insertion(+), 5 deletions(-)

--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -279,11 +279,10 @@ struct clk:

%pC pll1
%pCn pll1
- %pCr 1560000000

For printing struct clk structures. '%pC' and '%pCn' print the name
(Common Clock Framework) or address (legacy clock framework) of the
- structure; '%pCr' prints the current clock rate.
+ structure.

Passed by reference.

--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1391,9 +1391,6 @@ char *clock(char *buf, char *end, struct
return string(buf, end, NULL, spec);

switch (fmt[1]) {
- case 'r':
- return number(buf, end, clk_get_rate(clk), spec);
-
case 'n':
default:
#ifdef CONFIG_COMMON_CLK

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