From 2a1c7f53fd31e46f51780b61eb99fffef4c3c5a6 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 13 Jun 2013 12:53:42 +1000 Subject: [PATCH] sunrpc/cache: use cache_fresh_unlocked consistently and correctly. cache_fresh_unlocked() is called when a cache entry has been updated and ensures that if there were any pending upcalls, they are cleared. So every time we update a cache entry, we should call this, and this should be the only way that we try to clear pending calls (that sort of uniformity makes code sooo much easier to read). try_to_negate_entry() will (possibly) mark an entry as negative. If it doesn't, it is because the entry already is VALID. So the entry will be valid on exit, so it is appropriate to call cache_fresh_unlocked(). So tidy up try_to_negate_entry() to do that, and remove partial open-coded cache_fresh_unlocked() from the one call-site of try_to_negate_entry(). In the other branch of the 'switch(cache_make_upcall())', we again have a partial open-coded version of cache_fresh_unlocked(). Replace that with a real call. And again in cache_clean(), use a real call to cache_fresh_unlocked(). These call sites might previously have called cache_revisit_request() if CACHE_PENDING wasn't set. This is never necessary because cache_revisit_request() can only do anything if the item is in the cache_defer_hash, However any time that an item is added to the cache_defer_hash (setup_deferral), the code immediately tests CACHE_PENDING, and removes the entry again if it is clear. So all other places we only need to 'cache_revisit_request' if we've just cleared CACHE_PENDING. Reported-by: Bodo Stroesser Signed-off-by: NeilBrown Signed-off-by: J. Bruce Fields --- net/sunrpc/cache.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-) diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index 8e964ae8d7b5..29c463396a2d 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -228,15 +228,14 @@ static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h write_lock(&detail->hash_lock); rv = cache_is_valid(h); - if (rv != -EAGAIN) { - write_unlock(&detail->hash_lock); - return rv; + if (rv == -EAGAIN) { + set_bit(CACHE_NEGATIVE, &h->flags); + cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY); + rv = -ENOENT; } - set_bit(CACHE_NEGATIVE, &h->flags); - cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY); write_unlock(&detail->hash_lock); cache_fresh_unlocked(h, detail); - return -ENOENT; + return rv; } /* @@ -275,13 +274,10 @@ int cache_check(struct cache_detail *detail, if (!test_and_set_bit(CACHE_PENDING, &h->flags)) { switch (cache_make_upcall(detail, h)) { case -EINVAL: - clear_bit(CACHE_PENDING, &h->flags); - cache_revisit_request(h); rv = try_to_negate_entry(detail, h); break; case -EAGAIN: - clear_bit(CACHE_PENDING, &h->flags); - cache_revisit_request(h); + cache_fresh_unlocked(h, detail); break; } } @@ -457,9 +453,7 @@ static int cache_clean(void) current_index ++; spin_unlock(&cache_list_lock); if (ch) { - if (test_and_clear_bit(CACHE_PENDING, &ch->flags)) - cache_dequeue(current_detail, ch); - cache_revisit_request(ch); + cache_fresh_unlocked(ch, d); cache_put(ch, d); } } else -- 2.20.1