From c26d436cbf7a9549ec1073480a2e3f0d3f64e02d Mon Sep 17 00:00:00 2001 From: Andre Naujoks Date: Fri, 13 Sep 2013 19:37:12 +0200 Subject: lib: introduce upper case hex ascii helpers To be able to use the hex ascii functions in case sensitive environments the array hex_asc_upper[] and the needed functions for hex_byte_pack_upper() are introduced. Signed-off-by: Andre Naujoks Signed-off-by: David S. Miller --- lib/hexdump.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'lib') diff --git a/lib/hexdump.c b/lib/hexdump.c index 3f0494c..8499c81 100644 --- a/lib/hexdump.c +++ b/lib/hexdump.c @@ -14,6 +14,8 @@ const char hex_asc[] = "0123456789abcdef"; EXPORT_SYMBOL(hex_asc); +const char hex_asc_upper[] = "0123456789ABCDEF"; +EXPORT_SYMBOL(hex_asc_upper); /** * hex_to_bin - convert a hex digit to its real value -- cgit v1.1 From d2212b4dce596fee83e5c523400bf084f4cc816c Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 26 Sep 2013 17:27:00 +0100 Subject: lockref: allow relaxed cmpxchg64 variant for lockless updates The 64-bit cmpxchg operation on the lockref is ordered by virtue of hazarding between the cmpxchg operation and the reference count manipulation. On weakly ordered memory architectures (such as ARM), it can be of great benefit to omit the barrier instructions where they are not needed. This patch moves the lockless lockref code over to a cmpxchg64_relaxed operation, which doesn't provide barrier semantics. If the operation isn't defined, we simply #define it as the usual 64-bit cmpxchg macro. Cc: Waiman Long Signed-off-by: Will Deacon Signed-off-by: Linus Torvalds --- lib/lockref.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/lockref.c b/lib/lockref.c index 677d036c..e294ae4 100644 --- a/lib/lockref.c +++ b/lib/lockref.c @@ -4,6 +4,14 @@ #ifdef CONFIG_CMPXCHG_LOCKREF /* + * Allow weakly-ordered memory architectures to provide barrier-less + * cmpxchg semantics for lockref updates. + */ +#ifndef cmpxchg64_relaxed +# define cmpxchg64_relaxed cmpxchg64 +#endif + +/* * Note that the "cmpxchg()" reloads the "old" value for the * failure case. */ @@ -14,8 +22,9 @@ while (likely(arch_spin_value_unlocked(old.lock.rlock.raw_lock))) { \ struct lockref new = old, prev = old; \ CODE \ - old.lock_count = cmpxchg64(&lockref->lock_count, \ - old.lock_count, new.lock_count); \ + old.lock_count = cmpxchg64_relaxed(&lockref->lock_count, \ + old.lock_count, \ + new.lock_count); \ if (likely(old.lock_count == prev.lock_count)) { \ SUCCESS; \ } \ -- cgit v1.1 From 730d7d339884f20da28b59bf6f0a16af6400a113 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 23 Sep 2013 14:41:17 -0700 Subject: sysfs: Allow mounting without CONFIG_NET In kobj_ns_current_may_mount the default should be to allow the mount. The test is only for a single kobj_ns_type at a time, and unless there is a reason to prevent it the mounting sysfs should be allowed. Subsystems that are not registered can't have are not involved so can't have a reason to prevent mounting sysfs. This is a bug-fix to commit 7dc5dbc879bd ("sysfs: Restrict mounting sysfs") that came in via the userns tree during the 3.12 merge window. Reported-and-tested-by: James Hogan Signed-off-by: "Eric W. Biederman" Signed-off-by: Linus Torvalds --- lib/kobject.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'lib') diff --git a/lib/kobject.c b/lib/kobject.c index 9621751..669bf19 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -933,10 +933,7 @@ const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj) bool kobj_ns_current_may_mount(enum kobj_ns_type type) { - bool may_mount = false; - - if (type == KOBJ_NS_TYPE_NONE) - return true; + bool may_mount = true; spin_lock(&kobj_ns_type_lock); if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) && -- cgit v1.1 From 491f6f8e5fd9a57aaf03b6d6e3e153f1c27d8a46 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 23 Sep 2013 12:59:56 +0200 Subject: lockref: use arch_mutex_cpu_relax() in CMPXCHG_LOOP() Make use of arch_mutex_cpu_relax() so architectures can override the default cpu_relax() semantics. This is especially useful for s390, where cpu_relax() means that we yield() the current (virtual) cpu and therefore is very expensive, and would contradict the whole purpose of the lockless cmpxchg loop. Signed-off-by: Heiko Carstens --- lib/lockref.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/lockref.c b/lib/lockref.c index e294ae4..6f9d434 100644 --- a/lib/lockref.c +++ b/lib/lockref.c @@ -12,6 +12,14 @@ #endif /* + * Allow architectures to override the default cpu_relax() within CMPXCHG_LOOP. + * This is useful for architectures with an expensive cpu_relax(). + */ +#ifndef arch_mutex_cpu_relax +# define arch_mutex_cpu_relax() cpu_relax() +#endif + +/* * Note that the "cmpxchg()" reloads the "old" value for the * failure case. */ @@ -28,7 +36,7 @@ if (likely(old.lock_count == prev.lock_count)) { \ SUCCESS; \ } \ - cpu_relax(); \ + arch_mutex_cpu_relax(); \ } \ } while (0) -- cgit v1.1 From 0ff18e3734c248fa516b4be942b1196832ee936c Mon Sep 17 00:00:00 2001 From: Fengguang Wu Date: Wed, 9 Oct 2013 09:26:21 +0800 Subject: kobject: show debug info on delayed kobject release Useful for locating buggy drivers on kernel oops. It may add dozens of new lines to boot dmesg. DEBUG_KOBJECT_RELEASE is hopefully only enabled in debug kernels (like maybe the Fedora rawhide one, or at developers), so being a bit more verbose is likely ok. Acked-by: Russell King Cc: Greg Kroah-Hartman Signed-off-by: Fengguang Wu Signed-off-by: Linus Torvalds --- lib/kobject.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/kobject.c b/lib/kobject.c index 669bf19..084f7b1 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -592,7 +592,7 @@ static void kobject_release(struct kref *kref) { struct kobject *kobj = container_of(kref, struct kobject, kref); #ifdef CONFIG_DEBUG_KOBJECT_RELEASE - pr_debug("kobject: '%s' (%p): %s, parent %p (delayed)\n", + pr_info("kobject: '%s' (%p): %s, parent %p (delayed)\n", kobject_name(kobj), kobj, __func__, kobj->parent); INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup); schedule_delayed_work(&kobj->release, HZ); -- cgit v1.1