diff options
| -rw-r--r-- | kernel/sysctl_binary.c | 31 | ||||
| -rw-r--r-- | mm/page_alloc.c | 11 |
2 files changed, 37 insertions, 5 deletions
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c index 112533d5fc0..8f5d16e0707 100644 --- a/kernel/sysctl_binary.c +++ b/kernel/sysctl_binary.c @@ -1417,6 +1417,35 @@ static void deprecated_sysctl_warning(const int *name, int nlen) return; } +#define WARN_ONCE_HASH_BITS 8 +#define WARN_ONCE_HASH_SIZE (1<<WARN_ONCE_HASH_BITS) + +static DECLARE_BITMAP(warn_once_bitmap, WARN_ONCE_HASH_SIZE); + +#define FNV32_OFFSET 2166136261U +#define FNV32_PRIME 0x01000193 + +/* + * Print each legacy sysctl (approximately) only once. + * To avoid making the tables non-const use a external + * hash-table instead. + * Worst case hash collision: 6, but very rarely. + * NOTE! We don't use the SMP-safe bit tests. We simply + * don't care enough. + */ +static void warn_on_bintable(const int *name, int nlen) +{ + int i; + u32 hash = FNV32_OFFSET; + + for (i = 0; i < nlen; i++) + hash = (hash ^ name[i]) * FNV32_PRIME; + hash %= WARN_ONCE_HASH_SIZE; + if (__test_and_set_bit(hash, warn_once_bitmap)) + return; + deprecated_sysctl_warning(name, nlen); +} + static ssize_t do_sysctl(int __user *args_name, int nlen, void __user *oldval, size_t oldlen, void __user *newval, size_t newlen) { @@ -1431,7 +1460,7 @@ static ssize_t do_sysctl(int __user *args_name, int nlen, if (get_user(name[i], args_name + i)) return -EFAULT; - deprecated_sysctl_warning(name, nlen); + warn_on_bintable(name, nlen); return binary_sysctl(name, nlen, oldval, oldlen, newval, newlen); } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d79b9258056..4e9f5cc5fb5 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2402,13 +2402,14 @@ int numa_zonelist_order_handler(ctl_table *table, int write, { char saved_string[NUMA_ZONELIST_ORDER_LEN]; int ret; + static DEFINE_MUTEX(zl_order_mutex); + mutex_lock(&zl_order_mutex); if (write) - strncpy(saved_string, (char*)table->data, - NUMA_ZONELIST_ORDER_LEN); + strcpy(saved_string, (char*)table->data); ret = proc_dostring(table, write, buffer, length, ppos); if (ret) - return ret; + goto out; if (write) { int oldval = user_zonelist_order; if (__parse_numa_zonelist_order((char*)table->data)) { @@ -2421,7 +2422,9 @@ int numa_zonelist_order_handler(ctl_table *table, int write, } else if (oldval != user_zonelist_order) build_all_zonelists(); } - return 0; +out: + mutex_unlock(&zl_order_mutex); + return ret; } |