From: NeilBrown Date: Mon, 27 Mar 2006 09:15:08 +0000 (-0800) Subject: [PATCH] knfsd: Unexport cache_fresh and fix a small race X-Git-Tag: v2.6.17-rc1~427 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=ebd0cb1af3be2729cc1f574681dfba01fcf458d9;p=linux-2.6-omap-h63xx.git [PATCH] knfsd: Unexport cache_fresh and fix a small race Cache_fresh is now only used in cache.c, so unexport it. Part of cache_fresh (setting CACHE_VALID) should really be done under the lock, while part (calling cache_revisit_request etc) must be done outside the lock. So we split it up appropriately. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h index afc481dd02d..a37fead1873 100644 --- a/include/linux/sunrpc/cache.h +++ b/include/linux/sunrpc/cache.h @@ -165,8 +165,6 @@ static inline int cache_put(struct cache_head *h, struct cache_detail *cd) } extern void cache_init(struct cache_head *h); -extern void cache_fresh(struct cache_detail *detail, - struct cache_head *head, time_t expiry); extern int cache_check(struct cache_detail *detail, struct cache_head *h, struct cache_req *rqstp); extern void cache_flush(void); diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index b242f491cea..edcda4fd88e 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -96,6 +96,27 @@ struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, } EXPORT_SYMBOL(sunrpc_cache_lookup); + +static void queue_loose(struct cache_detail *detail, struct cache_head *ch); + +static int cache_fresh_locked(struct cache_head *head, time_t expiry) +{ + head->expiry_time = expiry; + head->last_refresh = get_seconds(); + return !test_and_set_bit(CACHE_VALID, &head->flags); +} + +static void cache_fresh_unlocked(struct cache_head *head, + struct cache_detail *detail, int new) +{ + if (new) + cache_revisit_request(head); + if (test_and_clear_bit(CACHE_PENDING, &head->flags)) { + cache_revisit_request(head); + queue_loose(detail, head); + } +} + struct cache_head *sunrpc_cache_update(struct cache_detail *detail, struct cache_head *new, struct cache_head *old, int hash) { @@ -105,6 +126,7 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail, */ struct cache_head **head; struct cache_head *tmp; + int is_new; if (!test_bit(CACHE_VALID, &old->flags)) { write_lock(&detail->hash_lock); @@ -113,9 +135,9 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail, set_bit(CACHE_NEGATIVE, &old->flags); else detail->update(old, new); - /* FIXME cache_fresh should come first */ + is_new = cache_fresh_locked(old, new->expiry_time); write_unlock(&detail->hash_lock); - cache_fresh(detail, old, new->expiry_time); + cache_fresh_unlocked(old, detail, is_new); return old; } write_unlock(&detail->hash_lock); @@ -138,9 +160,11 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail, tmp->next = *head; *head = tmp; cache_get(tmp); + is_new = cache_fresh_locked(tmp, new->expiry_time); + cache_fresh_locked(old, 0); write_unlock(&detail->hash_lock); - cache_fresh(detail, tmp, new->expiry_time); - cache_fresh(detail, old, 0); + cache_fresh_unlocked(tmp, detail, is_new); + cache_fresh_unlocked(old, detail, 0); detail->cache_put(old, detail); return tmp; } @@ -192,7 +216,8 @@ int cache_check(struct cache_detail *detail, clear_bit(CACHE_PENDING, &h->flags); if (rv == -EAGAIN) { set_bit(CACHE_NEGATIVE, &h->flags); - cache_fresh(detail, h, get_seconds()+CACHE_NEW_EXPIRY); + cache_fresh_unlocked(h, detail, + cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY)); rv = -ENOENT; } break; @@ -213,22 +238,6 @@ int cache_check(struct cache_detail *detail, return rv; } -static void queue_loose(struct cache_detail *detail, struct cache_head *ch); - -void cache_fresh(struct cache_detail *detail, - struct cache_head *head, time_t expiry) -{ - - head->expiry_time = expiry; - head->last_refresh = get_seconds(); - if (!test_and_set_bit(CACHE_VALID, &head->flags)) - cache_revisit_request(head); - if (test_and_clear_bit(CACHE_PENDING, &head->flags)) { - cache_revisit_request(head); - queue_loose(detail, head); - } -} - /* * caches need to be periodically cleaned. * For this we maintain a list of cache_detail and diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c index 40401196e7d..69b8238f3d1 100644 --- a/net/sunrpc/sunrpc_syms.c +++ b/net/sunrpc/sunrpc_syms.c @@ -105,7 +105,6 @@ EXPORT_SYMBOL(auth_unix_lookup); EXPORT_SYMBOL(cache_check); EXPORT_SYMBOL(cache_flush); EXPORT_SYMBOL(cache_purge); -EXPORT_SYMBOL(cache_fresh); EXPORT_SYMBOL(cache_init); EXPORT_SYMBOL(cache_register); EXPORT_SYMBOL(cache_unregister);