Commit-ID: fe2a5cd8aa038e2b02fda983afc2083e94c04b4f
Gitweb: http://git.kernel.org/tip/fe2a5cd8aa038e2b02fda983afc2083e94c04b4f
Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate: Wed, 24 May 2017 10:15:25 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Fri, 26 May 2017 10:10:40 +0200
ARM/hw_breakpoint: Use cpuhp_setup_state_cpuslocked()
arch_hw_breakpoint_init() holds get_online_cpus() while registerring the
hotplug callbacks.
cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.
Use cpuhp_setup_state_cpuslocked() to avoid the nested call. Convert
*_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20170524081548.170940729@xxxxxxxxxxxxx
---
arch/arm/kernel/hw_breakpoint.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index be3b3fb..63cb4c7 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -1090,7 +1090,7 @@ static int __init arch_hw_breakpoint_init(void)
* driven low on this core and there isn't an architected way to
* determine that.
*/
- get_online_cpus();
+ cpus_read_lock();
register_undef_hook(&debug_reg_hook);
/*
@@ -1098,15 +1098,16 @@ static int __init arch_hw_breakpoint_init(void)
* assume that a halting debugger will leave the world in a nice state
* for us.
*/
- ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm/hw_breakpoint:online",
- dbg_reset_online, NULL);
+ ret = cpuhp_setup_state_cpuslocked(CPUHP_AP_ONLINE_DYN,
+ "arm/hw_breakpoint:online",
+ dbg_reset_online, NULL);
unregister_undef_hook(&debug_reg_hook);
if (WARN_ON(ret < 0) || !cpumask_empty(&debug_err_mask)) {
core_num_brps = 0;
core_num_wrps = 0;
if (ret > 0)
cpuhp_remove_state_nocalls(ret);
- put_online_cpus();
+ cpus_read_unlock();
return 0;
}
@@ -1124,7 +1125,7 @@ static int __init arch_hw_breakpoint_init(void)
TRAP_HWBKPT, "watchpoint debug exception");
hook_ifault_code(FAULT_CODE_DEBUG, hw_breakpoint_pending, SIGTRAP,
TRAP_HWBKPT, "breakpoint debug exception");
- put_online_cpus();
+ cpus_read_unlock();
/* Register PM notifiers. */
pm_init();
--
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