From 471a930ad7d1b868456e835a67169a661ec73f65 Mon Sep 17 00:00:00 2001 From: Kinglong Mee Date: Wed, 8 Feb 2017 09:54:33 +0800 Subject: [PATCH] SUNRPC: Drop all entries from cache_detail when cache_purge() User always free the cache_detail after sunrpc_destroy_cache_detail(), so, it must cleanup up entries that left in the cache_detail, otherwise, NULL reference may be caused when using the left entries. Also, NeriBrown suggests "write a stand-alone cache_purge()." v3, move the cache_fresh_unlocked() out of write lock, v2, a stand-alone cache_purge(), not only for sunrpc_destroy_cache_detail Signed-off-by: Kinglong Mee Reviewed-by: NeilBrown Signed-off-by: J. Bruce Fields --- net/sunrpc/cache.c | 41 ++++++++++++++++++++++++++--------------- 1 file changed, 26 insertions(+), 15 deletions(-) diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index 502b9fe..f5d6c60 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -362,11 +362,6 @@ void sunrpc_destroy_cache_detail(struct cache_detail *cd) cache_purge(cd); spin_lock(&cache_list_lock); write_lock(&cd->hash_lock); - if (cd->entries) { - write_unlock(&cd->hash_lock); - spin_unlock(&cache_list_lock); - goto out; - } if (current_detail == cd) current_detail = NULL; list_del_init(&cd->others); @@ -376,9 +371,6 @@ void sunrpc_destroy_cache_detail(struct cache_detail *cd) /* module must be being unloaded so its safe to kill the worker */ cancel_delayed_work_sync(&cache_cleaner); } - return; -out: - printk(KERN_ERR "RPC: failed to unregister %s cache\n", cd->name); } EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail); @@ -497,13 +489,32 @@ EXPORT_SYMBOL_GPL(cache_flush); void cache_purge(struct cache_detail *detail) { - time_t now = seconds_since_boot(); - if (detail->flush_time >= now) - now = detail->flush_time + 1; - /* 'now' is the maximum value any 'last_refresh' can have */ - detail->flush_time = now; - detail->nextcheck = seconds_since_boot(); - cache_flush(); + struct cache_head *ch = NULL; + struct hlist_head *head = NULL; + struct hlist_node *tmp = NULL; + int i = 0; + + write_lock(&detail->hash_lock); + if (!detail->entries) { + write_unlock(&detail->hash_lock); + return; + } + + dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name); + for (i = 0; i < detail->hash_size; i++) { + head = &detail->hash_table[i]; + hlist_for_each_entry_safe(ch, tmp, head, cache_list) { + hlist_del_init(&ch->cache_list); + detail->entries--; + + set_bit(CACHE_CLEANED, &ch->flags); + write_unlock(&detail->hash_lock); + cache_fresh_unlocked(ch, detail); + cache_put(ch, detail); + write_lock(&detail->hash_lock); + } + } + write_unlock(&detail->hash_lock); } EXPORT_SYMBOL_GPL(cache_purge); -- 2.7.4