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cpu-hotplug: replace lock_cpu_hotplug() with get_online_cpus()

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Replace all lock_cpu_hotplug/unlock_cpu_hotplug from the kernel and use
get_online_cpus and put_online_cpus instead as it highlights the
refcount semantics in these operations.

The new API guarantees protection against the cpu-hotplug operation, but
it doesn't guarantee serialized access to any of the local data
structures. Hence the changes needs to be reviewed.

In case of pseries_add_processor/pseries_remove_processor, use
cpu_maps_update_begin()/cpu_maps_update_done() as we're modifying the
cpu_present_map there.

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Gautham R Shenoy
2008-01-25 21:08:02 +01:00
committed by Ingo Molnar
parent d221938c04
commit 86ef5c9a8e
15 changed files with 62 additions and 61 deletions
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8
drivers/lguest/x86/core.c
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@@ -459,7 +459,7 @@ void __init lguest_arch_host_init(void)
/* We don't need the complexity of CPUs coming and going while we're
* doing this. */
lock_cpu_hotplug();
get_online_cpus();
if (cpu_has_pge) { /* We have a broader idea of "global". */
/* Remember that this was originally set (for cleanup). */
cpu_had_pge = 1;
@@ -469,20 +469,20 @@ void __init lguest_arch_host_init(void)
/* Turn off the feature in the global feature set. */
clear_bit(X86_FEATURE_PGE, boot_cpu_data.x86_capability);
}
unlock_cpu_hotplug();
put_online_cpus();
};
/*:*/
void __exit lguest_arch_host_fini(void)
{
/* If we had PGE before we started, turn it back on now. */
lock_cpu_hotplug();
get_online_cpus();
if (cpu_had_pge) {
set_bit(X86_FEATURE_PGE, boot_cpu_data.x86_capability);
/* adjust_pge's argument "1" means set PGE. */
on_each_cpu(adjust_pge, (void *)1, 0, 1);
}
unlock_cpu_hotplug();
put_online_cpus();
}