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authorLinus Torvalds <torvalds@linux-foundation.org>2009-12-24 13:01:29 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-24 13:01:29 -0800
commit0b5e2588d8238b03df66c4e74769fd03ad84f694 (patch)
tree7a7baf0d8309a3473bf265d1354bb756d65a4a02
parent6067d7e4f05e5c08617cf95032867d892035e581 (diff)
parent443c6f145de813518c36ac6b6e4e08d9445337e7 (diff)
Merge branch 'sysctl' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc-2.6
* 'sysctl' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc-2.6: SYSCTL: Add a mutex to the page_alloc zone order sysctl SYSCTL: Print binary sysctl warnings (nearly) only once
-rw-r--r--kernel/sysctl_binary.c31
-rw-r--r--mm/page_alloc.c11
2 files changed, 37 insertions, 5 deletions
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index 112533d5fc08..8f5d16e0707a 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 d79b92580561..4e9f5cc5fb59 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;
}