lru_cache: introduce lc_get_cumulative()
New helper to be able to consolidate more updates
into a single transaction.
Without this, we can only grab a single refcount
on an updated element while preparing a transaction.
lc_get_cumulative - like lc_get; also finds to-be-changed elements
@lc: the lru cache to operate on
@enr: the label to look up
Unlike lc_get this also returns the element for @enr, if it is belonging to
a pending transaction, so the return values are like for lc_get(),
plus:
pointer to an element already on the "to_be_changed" list.
In this case, the cache was already marked %LC_DIRTY.
Caller needs to make sure that the pending transaction is completed,
before proceeding to actually use this element.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Fixed up by Jens to export lc_get_cumulative().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/lru_cache.h b/include/linux/lru_cache.h
index 4019013..4626228 100644
--- a/include/linux/lru_cache.h
+++ b/include/linux/lru_cache.h
@@ -256,6 +256,7 @@
extern void lc_set(struct lru_cache *lc, unsigned int enr, int index);
extern void lc_del(struct lru_cache *lc, struct lc_element *element);
+extern struct lc_element *lc_get_cumulative(struct lru_cache *lc, unsigned int enr);
extern struct lc_element *lc_try_get(struct lru_cache *lc, unsigned int enr);
extern struct lc_element *lc_find(struct lru_cache *lc, unsigned int enr);
extern struct lc_element *lc_get(struct lru_cache *lc, unsigned int enr);