diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig | 3 | ||||
| -rw-r--r-- | lib/Makefile | 2 | ||||
| -rw-r--r-- | lib/average.c | 61 | ||||
| -rw-r--r-- | lib/hexdump.c | 16 | ||||
| -rw-r--r-- | lib/kref.c | 30 | ||||
| -rw-r--r-- | lib/nlattr.c | 22 | ||||
| -rw-r--r-- | lib/percpu_counter.c | 8 |
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 @@ -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(); } |
