[added,to,the,4.1,stable,tree] driver-core: use 'dev' argument in dev_dbg_ratelimited stub

Message ID 20180301152116.1486-461-alexander.levin@microsoft.com
State New
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  • [added,to,the,4.1,stable,tree] driver-core: use 'dev' argument in dev_dbg_ratelimited stub
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Commit Message

Sasha Levin March 1, 2018, 3:27 p.m.
From: Arnd Bergmann <arnd@arndb.de>

This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.




[ Upstream commit 1f62ff34a90471d1b735bac2c79e894afc7c59bc ]

dev_dbg_ratelimited() is a macro that ignores its first argument when DEBUG is
not set, which can lead to unused variable warnings:

ethernet/mellanox/mlxsw/pci.c: In function 'mlxsw_pci_cqe_sdq_handle':
ethernet/mellanox/mlxsw/pci.c:646:18: warning: unused variable 'pdev' [-Wunused-variable]
ethernet/mellanox/mlxsw/pci.c: In function 'mlxsw_pci_cqe_rdq_handle':
ethernet/mellanox/mlxsw/pci.c:671:18: warning: unused variable 'pdev' [-Wunused-variable]

The macro already ensures that all its other arguments are silently
ignored by the compiler without triggering a warning, through the
use of the no_printk() macro, but the dev argument is not passed into

This changes the definition to use the same trick as no_printk() with
an if(0) that leads the compiler to not evaluate the side-effects but
still see that 'dev' might not be unused.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Fixes: 6f586e663e3b ("driver-core: Shut up dev_dbg_reatelimited() without DEBUG")
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
 include/linux/device.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/linux/device.h b/include/linux/device.h
index 98a1d9748eec..84a1c7e49c51 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -1208,8 +1208,11 @@  do {									\
 		dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__);	\
 } while (0)
-#define dev_dbg_ratelimited(dev, fmt, ...)			\
-	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
+#define dev_dbg_ratelimited(dev, fmt, ...)				\
+do {									\
+	if (0)								\
+		dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__);	\
+} while (0)