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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-03-25 20:42:07 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-18 21:38:22 +0300 |
| commit | dde8da6cffe73dab81aca3855e717e40db35178c (patch) | |
| tree | 8ba4ae7673a0106448a442033127669d8ea3658c /mm/mmu_notifier.c | |
| parent | f60d231a87c5c9f23f10e69996f396d46f5bf901 (diff) | |
| download | linux-dde8da6cffe73dab81aca3855e717e40db35178c.tar.xz | |
mm: Use static initialization for "srcu"
The MM-notifier code currently dynamically initializes the srcu_struct
named "srcu" at subsys_initcall() time, and includes a BUG_ON() to check
this initialization in do_mmu_notifier_register(). Unfortunately, there
is no foolproof way to verify that an srcu_struct has been initialized,
given the possibility of an srcu_struct being allocated on the stack or
on the heap. This means that creating an srcu_struct_is_initialized()
function is not a reasonable course of action. Nor is peppering
do_mmu_notifier_register() with SRCU-specific #ifdefs an attractive
alternative.
This commit therefore uses DEFINE_STATIC_SRCU() to initialize
this srcu_struct at compile time, thus eliminating both the
subsys_initcall()-time initialization and the runtime BUG_ON().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <linux-mm@kvack.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Diffstat (limited to 'mm/mmu_notifier.c')
| -rw-r--r-- | mm/mmu_notifier.c | 14 |
1 files changed, 1 insertions, 13 deletions
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index a7652acd2ab9..54ca54562928 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -21,7 +21,7 @@ #include <linux/slab.h> /* global SRCU for all MMs */ -static struct srcu_struct srcu; +DEFINE_STATIC_SRCU(srcu); /* * This function allows mmu_notifier::release callback to delay a call to @@ -252,12 +252,6 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn, BUG_ON(atomic_read(&mm->mm_users) <= 0); - /* - * Verify that mmu_notifier_init() already run and the global srcu is - * initialized. - */ - BUG_ON(!srcu.per_cpu_ref); - ret = -ENOMEM; mmu_notifier_mm = kmalloc(sizeof(struct mmu_notifier_mm), GFP_KERNEL); if (unlikely(!mmu_notifier_mm)) @@ -406,9 +400,3 @@ void mmu_notifier_unregister_no_release(struct mmu_notifier *mn, mmdrop(mm); } EXPORT_SYMBOL_GPL(mmu_notifier_unregister_no_release); - -static int __init mmu_notifier_init(void) -{ - return init_srcu_struct(&srcu); -} -subsys_initcall(mmu_notifier_init); |