aboutsummaryrefslogtreecommitdiff
path: root/lib
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2013-05-08 11:51:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-05-08 11:51:05 -0700
commitebb37277796269da36a8bc5d72ed1e8e1fb7d34b (patch)
tree0ded627a62a5cec70b18d12825dd858855c135d3 /lib
parent4de13d7aa8f4d02f4dc99d4609575659f92b3c5a (diff)
parentf50efd2fdbd9b35b11f5778ed85beb764184bda9 (diff)
downloadlinux-ebb37277796269da36a8bc5d72ed1e8e1fb7d34b.tar.gz
Merge branch 'for-3.10/drivers' of git://git.kernel.dk/linux-block
Pull block driver updates from Jens Axboe: "It might look big in volume, but when categorized, not a lot of drivers are touched. The pull request contains: - mtip32xx fixes from Micron. - A slew of drbd updates, this time in a nicer series. - bcache, a flash/ssd caching framework from Kent. - Fixes for cciss" * 'for-3.10/drivers' of git://git.kernel.dk/linux-block: (66 commits) bcache: Use bd_link_disk_holder() bcache: Allocator cleanup/fixes cciss: bug fix to prevent cciss from loading in kdump crash kernel cciss: add cciss_allow_hpsa module parameter drivers/block/mg_disk.c: add CONFIG_PM_SLEEP to suspend/resume functions mtip32xx: Workaround for unaligned writes bcache: Make sure blocksize isn't smaller than device blocksize bcache: Fix merge_bvec_fn usage for when it modifies the bvm bcache: Correctly check against BIO_MAX_PAGES bcache: Hack around stuff that clones up to bi_max_vecs bcache: Set ra_pages based on backing device's ra_pages bcache: Take data offset from the bdev superblock. mtip32xx: mtip32xx: Disable TRIM support mtip32xx: fix a smatch warning bcache: Disable broken btree fuzz tester bcache: Fix a format string overflow bcache: Fix a minor memory leak on device teardown bcache: Documentation updates bcache: Use WARN_ONCE() instead of __WARN() bcache: Add missing #include <linux/prefetch.h> ...
Diffstat (limited to 'lib')
-rw-r--r--lib/lru_cache.c56
1 files changed, 46 insertions, 10 deletions
diff --git a/lib/lru_cache.c b/lib/lru_cache.c
index 8335d39d2cc..4a83ecd0365 100644
--- a/lib/lru_cache.c
+++ b/lib/lru_cache.c
@@ -365,7 +365,13 @@ static int lc_unused_element_available(struct lru_cache *lc)
return 0;
}
-static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, bool may_change)
+/* used as internal flags to __lc_get */
+enum {
+ LC_GET_MAY_CHANGE = 1,
+ LC_GET_MAY_USE_UNCOMMITTED = 2,
+};
+
+static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, unsigned int flags)
{
struct lc_element *e;
@@ -380,22 +386,31 @@ static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, bool
* this enr is currently being pulled in already,
* and will be available once the pending transaction
* has been committed. */
- if (e && e->lc_new_number == e->lc_number) {
+ if (e) {
+ if (e->lc_new_number != e->lc_number) {
+ /* It has been found above, but on the "to_be_changed"
+ * list, not yet committed. Don't pull it in twice,
+ * wait for the transaction, then try again...
+ */
+ if (!(flags & LC_GET_MAY_USE_UNCOMMITTED))
+ RETURN(NULL);
+ /* ... unless the caller is aware of the implications,
+ * probably preparing a cumulative transaction. */
+ ++e->refcnt;
+ ++lc->hits;
+ RETURN(e);
+ }
+ /* else: lc_new_number == lc_number; a real hit. */
++lc->hits;
if (e->refcnt++ == 0)
lc->used++;
list_move(&e->list, &lc->in_use); /* Not evictable... */
RETURN(e);
}
+ /* e == NULL */
++lc->misses;
- if (!may_change)
- RETURN(NULL);
-
- /* It has been found above, but on the "to_be_changed" list, not yet
- * committed. Don't pull it in twice, wait for the transaction, then
- * try again */
- if (e)
+ if (!(flags & LC_GET_MAY_CHANGE))
RETURN(NULL);
/* To avoid races with lc_try_lock(), first, mark us dirty
@@ -477,7 +492,27 @@ static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, bool
*/
struct lc_element *lc_get(struct lru_cache *lc, unsigned int enr)
{
- return __lc_get(lc, enr, 1);
+ return __lc_get(lc, enr, LC_GET_MAY_CHANGE);
+}
+
+/**
+ * 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.
+ */
+struct lc_element *lc_get_cumulative(struct lru_cache *lc, unsigned int enr)
+{
+ return __lc_get(lc, enr, LC_GET_MAY_CHANGE|LC_GET_MAY_USE_UNCOMMITTED);
}
/**
@@ -648,3 +683,4 @@ EXPORT_SYMBOL(lc_seq_printf_stats);
EXPORT_SYMBOL(lc_seq_dump_details);
EXPORT_SYMBOL(lc_try_lock);
EXPORT_SYMBOL(lc_is_used);
+EXPORT_SYMBOL(lc_get_cumulative);