From ebd15302dc0ba1b8761600c20854f5371e7bae1e Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Sat, 5 Aug 2006 12:15:06 -0700 Subject: [PATCH] [PATCH] memory hotadd fixes: enhance collision check This patch is for collision check enhancement for memory hot add. It's better to do resouce collision check before doing memory hot add, which will touch memory management structures. And add_section() should check section exists or not before calling sparse_add_one_section(). (sparse_add_one_section() will do another check anyway. but checking in memory_hotplug.c will be easy to understand.) Signed-off-by: KAMEZAWA Hiroyuki Cc: keith mannthey Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 26f1840879d6..c37319542b70 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -52,6 +52,9 @@ static int __add_section(struct zone *zone, unsigned long phys_start_pfn) int nr_pages = PAGES_PER_SECTION; int ret; + if (pfn_valid(phys_start_pfn)) + return -EEXIST; + ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); if (ret < 0) @@ -220,10 +223,9 @@ static void rollback_node_hotadd(int nid, pg_data_t *pgdat) } /* add this memory to iomem resource */ -static int register_memory_resource(u64 start, u64 size) +static struct resource *register_memory_resource(u64 start, u64 size) { struct resource *res; - int ret = 0; res = kzalloc(sizeof(struct resource), GFP_KERNEL); BUG_ON(!res); @@ -235,9 +237,18 @@ static int register_memory_resource(u64 start, u64 size) printk("System RAM resource %llx - %llx cannot be added\n", (unsigned long long)res->start, (unsigned long long)res->end); kfree(res); - ret = -EEXIST; + res = NULL; } - return ret; + return res; +} + +static void release_memory_resource(struct resource *res) +{ + if (!res) + return; + release_resource(res); + kfree(res); + return; } @@ -246,8 +257,13 @@ int add_memory(int nid, u64 start, u64 size) { pg_data_t *pgdat = NULL; int new_pgdat = 0; + struct resource *res; int ret; + res = register_memory_resource(start, size); + if (!res) + return -EEXIST; + if (!node_online(nid)) { pgdat = hotadd_new_pgdat(nid, start); if (!pgdat) @@ -277,14 +293,13 @@ int add_memory(int nid, u64 start, u64 size) BUG_ON(ret); } - /* register this memory as resource */ - ret = register_memory_resource(start, size); - return ret; error: /* rollback pgdat allocation and others */ if (new_pgdat) rollback_node_hotadd(nid, pgdat); + if (res) + release_memory_resource(res); return ret; }