cache_key_alloc
struct pcache_cache_key *cache_key_alloc(struct pcache_cache_tree *cache_tree, gfp_t gfp_mask);
return cache_key_alloc(ctx->cache_tree, GFP_NOWAIT);
walk_ctx.pre_alloc_key = cache_key_alloc(cache_tree, GFP_NOIO);
key = cache_key_alloc(&cache->req_key_tree, GFP_NOIO);
key = cache_key_alloc(&cache->req_key_tree, gfp_mask);
key = cache_key_alloc(&cache->req_key_tree, GFP_NOIO);
key = cache_key_alloc(&cache->writeback_key_tree, GFP_NOIO);