7 files changed, 126 insertions, 16 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index fa9bf2c06199..3116aa631af6 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -210,4 +210,7 @@ config GENERIC_ATOMIC64
 config LRU_CACHE
         tristate
 
+config AVERAGE
+        bool
+
 endmenu
diff --git a/lib/Makefile b/lib/Makefile
index 9e2db72d128e..d7b6e30a3a1e 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -106,6 +106,8 @@ obj-$(CONFIG_GENERIC_ATOMIC64) += atomic64.o
 
 obj-$(CONFIG_ATOMIC64_SELFTEST) += atomic64_test.o
 
+obj-$(CONFIG_AVERAGE) += average.o
+
 hostprogs-y     := gen_crc32table
 clean-files     := crc32table.h
 
diff --git a/lib/average.c b/lib/average.c
new file mode 100644
index 000000000000..5576c2841496
--- /dev/null
+++ b/lib/average.c
@@ -0,0 +1,61 @@
+/*
+ * lib/average.c
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/average.h>
+#include <linux/bug.h>
+#include <linux/log2.h>
+
+/**
+ * DOC: Exponentially Weighted Moving Average (EWMA)
+ *
+ * These are generic functions for calculating Exponentially Weighted Moving
+ * Averages (EWMA). We keep a structure with the EWMA parameters and a scaled
+ * up internal representation of the average value to prevent rounding errors.
+ * The factor for scaling up and the exponential weight (or decay rate) have to
+ * be specified thru the init fuction. The structure should not be accessed
+ * directly but only thru the helper functions.
+ */
+
+/**
+ * ewma_init() - Initialize EWMA parameters
+ * @avg: Average structure
+ * @factor: Factor to use for the scaled up internal value. The maximum value
+ *      of averages can be ULONG_MAX/(factor*weight). For performance reasons
+ *      factor has to be a power of 2.
+ * @weight: Exponential weight, or decay rate. This defines how fast the
+ *      influence of older values decreases. For performance reasons weight has
+ *      to be a power of 2.
+ *
+ * Initialize the EWMA parameters for a given struct ewma @avg.
+ */
+void ewma_init(struct ewma *avg, unsigned long factor, unsigned long weight)
+{
+        WARN_ON(!is_power_of_2(weight) || !is_power_of_2(factor));
+
+        avg->weight = ilog2(weight);
+        avg->factor = ilog2(factor);
+        avg->internal = 0;
+}
+EXPORT_SYMBOL(ewma_init);
+
+/**
+ * ewma_add() - Exponentially weighted moving average (EWMA)
+ * @avg: Average structure
+ * @val: Current value
+ *
+ * Add a sample to the average.
+ */
+struct ewma *ewma_add(struct ewma *avg, unsigned long val)
+{
+        avg->internal = avg->internal  ?
+                (((avg->internal << avg->weight) - avg->internal) +
+                        (val << avg->factor)) >> avg->weight :
+                (val << avg->factor);
+        return avg;
+}
+EXPORT_SYMBOL(ewma_add);
diff --git a/lib/hexdump.c b/lib/hexdump.c
index 5d7a4802c562..b66b2bd67952 100644
--- a/lib/hexdump.c
+++ b/lib/hexdump.c
@@ -34,6 +34,22 @@ int hex_to_bin(char ch)
 EXPORT_SYMBOL(hex_to_bin);
 
 /**
+ * hex2bin - convert an ascii hexadecimal string to its binary representation
+ * @dst: binary result
+ * @src: ascii hexadecimal string
+ * @count: result length
+ */
+void hex2bin(u8 *dst, const char *src, size_t count)
+{
+        while (count--) {
+                *dst = hex_to_bin(*src++) << 4;
+                *dst += hex_to_bin(*src++);
+                dst++;
+        }
+}
+EXPORT_SYMBOL(hex2bin);
+
+/**
  * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
  * @buf: data blob to dump
  * @len: number of bytes in the @buf
diff --git a/lib/kref.c b/lib/kref.c
index d3d227a08a4b..3efb882b11db 100644
--- a/lib/kref.c
+++ b/lib/kref.c
@@ -62,6 +62,36 @@ int kref_put(struct kref *kref, void (*release)(struct kref *kref))
         return 0;
 }
 
+
+/**
+ * kref_sub - subtract a number of refcounts for object.
+ * @kref: object.
+ * @count: Number of recounts to subtract.
+ * @release: pointer to the function that will clean up the object when the
+ *           last reference to the object is released.
+ *           This pointer is required, and it is not acceptable to pass kfree
+ *           in as this function.
+ *
+ * Subtract @count from the refcount, and if 0, call release().
+ * Return 1 if the object was removed, otherwise return 0.  Beware, if this
+ * function returns 0, you still can not count on the kref from remaining in
+ * memory.  Only use the return value if you want to see if the kref is now
+ * gone, not present.
+ */
+int kref_sub(struct kref *kref, unsigned int count,
+             void (*release)(struct kref *kref))
+{
+        WARN_ON(release == NULL);
+        WARN_ON(release == (void (*)(struct kref *))kfree);
+
+        if (atomic_sub_and_test((int) count, &kref->refcount)) {
+                release(kref);
+                return 1;
+        }
+        return 0;
+}
+
 EXPORT_SYMBOL(kref_init);
 EXPORT_SYMBOL(kref_get);
 EXPORT_SYMBOL(kref_put);
+EXPORT_SYMBOL(kref_sub);
diff --git a/lib/nlattr.c b/lib/nlattr.c
index c4706eb98d3d..00e8a02681a6 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -15,7 +15,7 @@
 #include <linux/types.h>
 #include <net/netlink.h>
 
-static u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = {
+static const u16 nla_attr_minlen[NLA_TYPE_MAX+1] = {
         [NLA_U8]        = sizeof(u8),
         [NLA_U16]       = sizeof(u16),
         [NLA_U32]       = sizeof(u32),
@@ -23,7 +23,7 @@ static u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = {
         [NLA_NESTED]    = NLA_HDRLEN,
 };
 
-static int validate_nla(struct nlattr *nla, int maxtype,
+static int validate_nla(const struct nlattr *nla, int maxtype,
                         const struct nla_policy *policy)
 {
         const struct nla_policy *pt;
@@ -115,10 +115,10 @@ static int validate_nla(struct nlattr *nla, int maxtype,
  *
  * Returns 0 on success or a negative error code.
  */
-int nla_validate(struct nlattr *head, int len, int maxtype,
+int nla_validate(const struct nlattr *head, int len, int maxtype,
                  const struct nla_policy *policy)
 {
-        struct nlattr *nla;
+        const struct nlattr *nla;
         int rem, err;
 
         nla_for_each_attr(nla, head, len, rem) {
@@ -173,10 +173,10 @@ nla_policy_len(const struct nla_policy *p, int n)
  *
  * Returns 0 on success or a negative error code.
  */
-int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len,
-              const struct nla_policy *policy)
+int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
+              int len, const struct nla_policy *policy)
 {
-        struct nlattr *nla;
+        const struct nlattr *nla;
         int rem, err;
 
         memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
@@ -191,7 +191,7 @@ int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len,
                                         goto errout;
                         }
 
-                        tb[type] = nla;
+                        tb[type] = (struct nlattr *)nla;
                 }
         }
 
@@ -212,14 +212,14 @@ errout:
  *
  * Returns the first attribute in the stream matching the specified type.
  */
-struct nlattr *nla_find(struct nlattr *head, int len, int attrtype)
+struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
 {
-        struct nlattr *nla;
+        const struct nlattr *nla;
         int rem;
 
         nla_for_each_attr(nla, head, len, rem)
                 if (nla_type(nla) == attrtype)
-                        return nla;
+                        return (struct nlattr *)nla;
 
         return NULL;
 }
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index 604678d7d06d..28f2c33c6b53 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -72,18 +72,16 @@ EXPORT_SYMBOL(percpu_counter_set);
 void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
 {
         s64 count;
-        s32 *pcount;
 
         preempt_disable();
-        pcount = this_cpu_ptr(fbc->counters);
-        count = *pcount + amount;
+        count = __this_cpu_read(*fbc->counters) + amount;
         if (count >= batch || count <= -batch) {
                 spin_lock(&fbc->lock);
                 fbc->count += count;
-                *pcount = 0;
+                __this_cpu_write(*fbc->counters, 0);
                 spin_unlock(&fbc->lock);
         } else {
-                *pcount = count;
+                __this_cpu_write(*fbc->counters, count);
         }
         preempt_enable();
 }