x86/apic: Silence -Wtype-limits compiler warnings [Linux 4.9.188]

This Linux kernel change "x86/apic: Silence -Wtype-limits compiler warnings" is included in the Linux 4.9.188 release. This change is authored by Qian Cai <cai [at] lca.pw> on Mon Jul 8 17:36:45 2019 -0400. The commit for this change in Linux stable tree is d4ce30c (patch) which is from upstream commit ec63355. The same Linux upstream change may have been applied to various maintained Linux releases and you can find all Linux releases containing changes from upstream ec63355.

x86/apic: Silence -Wtype-limits compiler warnings

[ Upstream commit ec6335586953b0df32f83ef696002063090c7aef ]

There are many compiler warnings like this,

In file included from ./arch/x86/include/asm/smp.h:13,
                 from ./arch/x86/include/asm/mmzone_64.h:11,
                 from ./arch/x86/include/asm/mmzone.h:5,
                 from ./include/linux/mmzone.h:969,
                 from ./include/linux/gfp.h:6,
                 from ./include/linux/mm.h:10,
                 from arch/x86/kernel/apic/io_apic.c:34:
arch/x86/kernel/apic/io_apic.c: In function 'check_timer':
./arch/x86/include/asm/apic.h:37:11: warning: comparison of unsigned
expression >= 0 is always true [-Wtype-limits]
   if ((v) <= apic_verbosity) \
           ^~
arch/x86/kernel/apic/io_apic.c:2160:2: note: in expansion of macro
'apic_printk'
  apic_printk(APIC_QUIET, KERN_INFO "..TIMER: vector=0x%02X "
  ^~~~~~~~~~~
./arch/x86/include/asm/apic.h:37:11: warning: comparison of unsigned
expression >= 0 is always true [-Wtype-limits]
   if ((v) <= apic_verbosity) \
           ^~
arch/x86/kernel/apic/io_apic.c:2207:4: note: in expansion of macro
'apic_printk'
    apic_printk(APIC_QUIET, KERN_ERR "..MP-BIOS bug: "
    ^~~~~~~~~~~

APIC_QUIET is 0, so silence them by making apic_verbosity type int.

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1562621805-24789-1-git-send-email-cai@lca.pw
Signed-off-by: Sasha Levin <sashal@kernel.org>

There are 4 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 arch/x86/include/asm/apic.h | 2 +-
 arch/x86/kernel/apic/apic.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 2188b5a..f39fd34 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -50,7 +50,7 @@ static inline void generic_apic_probe(void)

 #ifdef CONFIG_X86_LOCAL_APIC

-extern unsigned int apic_verbosity;
+extern int apic_verbosity;
 extern int local_apic_timer_c2_ok;

 extern int disable_apic;
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 4f2af1e..cc9a6f6 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -183,7 +183,7 @@ static __init int setup_apicpmtimer(char *s)
 /*
  * Debug level, exported for io_apic.c
  */
-unsigned int apic_verbosity;
+int apic_verbosity;

 int pic_mode;

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