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author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2015-09-09 23:24:01 +0200 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2015-10-01 09:05:17 -0400 |
commit | 79ac6ef521075d0f40805df77e8890c55f538fe4 (patch) | |
tree | cf353ec399027ddd9f93a958004cc61777c1d9a9 | |
parent | 37aea98b84c0ce2ac638510fefeed9f8f920bd34 (diff) | |
download | linux-stable-79ac6ef521075d0f40805df77e8890c55f538fe4.tar.gz linux-stable-79ac6ef521075d0f40805df77e8890c55f538fe4.tar.bz2 linux-stable-79ac6ef521075d0f40805df77e8890c55f538fe4.zip |
tracing: Use kstrdup_const instead of private implementation
The kernel now has kstrdup_const/kfree_const for reusing .rodata
(typically string literals) when possible; there's no reason to
duplicate that logic in the tracing system. Moreover, as the comment
above core_kernel_data states, it may not always return true for
.rodata - that is for example the case on x86_64, where we thus end up
kstrdup'ing all the passed-in strings.
Arguably, testing for .rodata explicitly (as kstrdup_const does) is
also more correct: I don't think one is supposed to be able to change
the name after creating the event_subsystem by passing the address of
a static char (but non-const) array.
Link: http://lkml.kernel.org/r/1441833841-12955-1-git-send-email-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r-- | kernel/trace/trace_events.c | 24 |
1 files changed, 8 insertions, 16 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 57c9e709772c..d120cfe3cca7 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -38,21 +38,19 @@ static LIST_HEAD(ftrace_common_fields); static struct kmem_cache *field_cachep; static struct kmem_cache *file_cachep; -#define SYSTEM_FL_FREE_NAME (1 << 31) - static inline int system_refcount(struct event_subsystem *system) { - return system->ref_count & ~SYSTEM_FL_FREE_NAME; + return system->ref_count; } static int system_refcount_inc(struct event_subsystem *system) { - return (system->ref_count++) & ~SYSTEM_FL_FREE_NAME; + return system->ref_count++; } static int system_refcount_dec(struct event_subsystem *system) { - return (--system->ref_count) & ~SYSTEM_FL_FREE_NAME; + return --system->ref_count; } /* Double loops, do not use break, only goto's work */ @@ -461,8 +459,7 @@ static void __put_system(struct event_subsystem *system) kfree(filter->filter_string); kfree(filter); } - if (system->ref_count & SYSTEM_FL_FREE_NAME) - kfree(system->name); + kfree_const(system->name); kfree(system); } @@ -1493,13 +1490,9 @@ create_new_subsystem(const char *name) system->ref_count = 1; /* Only allocate if dynamic (kprobes and modules) */ - if (!core_kernel_data((unsigned long)name)) { - system->ref_count |= SYSTEM_FL_FREE_NAME; - system->name = kstrdup(name, GFP_KERNEL); - if (!system->name) - goto out_free; - } else - system->name = name; + system->name = kstrdup_const(name, GFP_KERNEL); + if (!system->name) + goto out_free; system->filter = NULL; @@ -1512,8 +1505,7 @@ create_new_subsystem(const char *name) return system; out_free: - if (system->ref_count & SYSTEM_FL_FREE_NAME) - kfree(system->name); + kfree_const(system->name); kfree(system); return NULL; } |