diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/mmu_notifier.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index d1094c2d5fb6..b60673a8e0bb 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -234,15 +234,57 @@ struct mmu_notifier { }; /** + * struct mmu_interval_notifier_finish - mmu_interval_notifier two-pass abstraction + * @link: Lockless list link for the notifiers pending pass list + * @notifier: The mmu_interval_notifier for which the finish pass is called. + * + * Allocate, typically using GFP_NOWAIT in the interval notifier's start pass. + * Note that with a large number of notifiers implementing two passes, + * allocation with GFP_NOWAIT will become increasingly likely to fail, so consider + * implementing a small pool instead of using kmalloc() allocations. + * + * If the implementation needs to pass data between the start and the finish passes, + * the recommended way is to embed struct mmu_interval_notifier_finish into a larger + * structure that also contains the data needed to be shared. Keep in mind that + * a notifier callback can be invoked in parallel, and each invocation needs its + * own struct mmu_interval_notifier_finish. + * + * If allocation fails, then the &mmu_interval_notifier_ops->invalidate_start op + * needs to implements the full notifier functionality. Please refer to its + * documentation. + */ +struct mmu_interval_notifier_finish { + struct llist_node link; + struct mmu_interval_notifier *notifier; +}; + +/** * struct mmu_interval_notifier_ops * @invalidate: Upon return the caller must stop using any SPTEs within this * range. This function can sleep. Return false only if sleeping * was required but mmu_notifier_range_blockable(range) is false. + * @invalidate_start: Similar to @invalidate, but intended for two-pass notifier + * callbacks where the call to @invalidate_start is the first + * pass and any struct mmu_interval_notifier_finish pointer + * returned in the @finish parameter describes the finish pass. + * If *@finish is %NULL on return, then no final pass will be + * called, and @invalidate_start needs to implement the full + * notifier, behaving like @invalidate. The value of *@finish + * is guaranteed to be %NULL at function entry. + * @invalidate_finish: Called as the second pass for any notifier that returned + * a non-NULL *@finish from @invalidate_start. The @finish + * pointer passed here is the same one returned by + * @invalidate_start. */ struct mmu_interval_notifier_ops { bool (*invalidate)(struct mmu_interval_notifier *interval_sub, const struct mmu_notifier_range *range, unsigned long cur_seq); + bool (*invalidate_start)(struct mmu_interval_notifier *interval_sub, + const struct mmu_notifier_range *range, + unsigned long cur_seq, + struct mmu_interval_notifier_finish **finish); + void (*invalidate_finish)(struct mmu_interval_notifier_finish *finish); }; struct mmu_interval_notifier { |