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-rw-r--r--lib/Kconfig3
-rw-r--r--lib/Makefile2
-rw-r--r--lib/average.c61
-rw-r--r--lib/hexdump.c16
-rw-r--r--lib/kref.c30
-rw-r--r--lib/nlattr.c22
-rw-r--r--lib/percpu_counter.c8
7 files changed, 126 insertions, 16 deletions
diff --git a/lib/Kconfig b/lib/Kconfig
index fa9bf2c..3116aa6 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 9e2db72..d7b6e30a 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 0000000..5576c28
--- /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 5d7a480..b66b2bd 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 d3d227a..3efb882 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 c4706eb..00e8a02 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 604678d..28f2c33 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();
}
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