[ovs-dev] [PATCH v2 03/11] datapath: compat: Introduce static key support

[Darrell Ball]

Thanks for the patch Yi-hung

On 8/1/18, 5:42 PM, "ovs-dev-bounces at openvswitch.org on behalf of Yi-Hung Wei" <ovs-dev-bounces at openvswitch.org on behalf of yihung.wei at gmail.com> wrote:

    This is a feature that is needed for a follow up patch
    in ovs kernel datapath.

It is usually implied that patch in a series is needed by a subsequent patch in the same series.
Would you mind expanding the commit message on the general utility?

Also, the upstream commit id is embedded in the file, static_key.h

    + * This backport is based on upstream net-next commit 11276d5306b8
    + * ("locking/static_keys: Add a new static_key interface").

Would it be possible to bring it into the commit message also?


    
    Signed-off-by: Yi-Hung Wei <yihung.wei at gmail.com>
    ---
     acinclude.m4                                     |  3 +
     datapath/linux/Modules.mk                        |  1 +
     datapath/linux/compat/include/linux/static_key.h | 70 ++++++++++++++++++++++++
     3 files changed, 74 insertions(+)
     create mode 100644 datapath/linux/compat/include/linux/static_key.h
    
    diff --git a/acinclude.m4 b/acinclude.m4
    index 96fcad55a7cb..341edbbd70f1 100644
    --- a/acinclude.m4
    +++ b/acinclude.m4
    @@ -467,6 +467,9 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
       OVS_GREP_IFELSE([$KSRC/include/linux/err.h], [IS_ERR_OR_NULL])
       OVS_GREP_IFELSE([$KSRC/include/linux/err.h], [PTR_ERR_OR_ZERO])
     
    +  OVS_GREP_IFELSE([$KSRC/include/linux/jump_label.h], [DEFINE_STATIC_KEY_FALSE],
    +                  [OVS_DEFINE([HAVE_UPSTREAM_STATIC_KEY])])
    +
       OVS_GREP_IFELSE([$KSRC/include/linux/etherdevice.h], [eth_hw_addr_random])
       OVS_GREP_IFELSE([$KSRC/include/linux/etherdevice.h], [ether_addr_copy])
     
    diff --git a/datapath/linux/Modules.mk b/datapath/linux/Modules.mk
    index f5c3b6580ad7..2fec6500e7c8 100644
    --- a/datapath/linux/Modules.mk
    +++ b/datapath/linux/Modules.mk
    @@ -63,6 +63,7 @@ openvswitch_headers += \
     	linux/compat/include/linux/reciprocal_div.h \
     	linux/compat/include/linux/rtnetlink.h \
     	linux/compat/include/linux/skbuff.h \
    +	linux/compat/include/linux/static_key.h \
     	linux/compat/include/linux/stddef.h \
     	linux/compat/include/linux/types.h \
     	linux/compat/include/linux/u64_stats_sync.h \
    diff --git a/datapath/linux/compat/include/linux/static_key.h b/datapath/linux/compat/include/linux/static_key.h
    new file mode 100644
    index 000000000000..ea59e3e285a1
    --- /dev/null
    +++ b/datapath/linux/compat/include/linux/static_key.h
    @@ -0,0 +1,70 @@
    +#ifndef _STATIC_KEY_WRAPPER_H
    +#define _STATIC_KEY_WRAPPER_H
    +
    +#include_next <linux/static_key.h>
    +#ifndef HAVE_UPSTREAM_STATIC_KEY
    +/*
    + * This backport is based on upstream net-next commit 11276d5306b8
    + * ("locking/static_keys: Add a new static_key interface").
    + *
    + * For kernel that does not support the new static key interface,
    + * we do not backport the jump label support but the fall back version
    + * of static key that is simply a conditional branch.
    + */
    +
    +struct static_key_true {
    +	struct static_key key;
    +};
    +
    +struct static_key_false {
    +	struct static_key key;
    +};
    +
    +#define rpl_STATIC_KEY_INIT_TRUE	{ .enabled = ATOMIC_INIT(1) }
    +#define rpl_STATIC_KEY_INIT_FALSE	{ .enabled = ATOMIC_INIT(0) }
    +
    +#define STATIC_KEY_TRUE_INIT	\
    +	(struct static_key_true) { .key = rpl_STATIC_KEY_INIT_TRUE,  }
    +#define STATIC_KEY_FALSE_INIT	\
    +	(struct static_key_false){ .key = rpl_STATIC_KEY_INIT_FALSE, }
    +
    +#define DEFINE_STATIC_KEY_TRUE(name)	\
    +	struct static_key_true name = STATIC_KEY_TRUE_INIT
    +
    +#define DEFINE_STATIC_KEY_FALSE(name)	\
    +	struct static_key_false name = STATIC_KEY_FALSE_INIT
    +
    +static inline int rpl_static_key_count(struct static_key *key)
    +{
    +	return atomic_read(&key->enabled);
    +}
    +
    +static inline void rpl_static_key_enable(struct static_key *key)
    +{
    +	int count = rpl_static_key_count(key);
    +
    +	WARN_ON_ONCE(count < 0 || count > 1);
    +
    +	if (!count)
    +		static_key_slow_inc(key);
    +}
    +
    +static inline void rpl_static_key_disable(struct static_key *key)
    +{
    +	int count = rpl_static_key_count(key);
    +
    +	WARN_ON_ONCE(count < 0 || count > 1);
    +
    +	if (count)
    +		static_key_slow_dec(key);
    +}
    +
    +#define static_branch_likely(x)		likely(static_key_enabled(&(x)->key))
    +#define static_branch_unlikely(x)	unlikely(static_key_enabled(&(x)->key))
    +
    +#define static_branch_enable(x)		rpl_static_key_enable(&(x)->key)
    +#define static_branch_disable(x)	rpl_static_key_disable(&(x)->key)
    +
    +#endif /* HAVE_UPSTREAM_STATIC_KEY */
    +
    +#endif /* _STATIC_KEY_WRAPPER_H */
    -- 
    2.7.4
    
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