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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-10-31 00:21:00 +0300 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-11-11 04:39:40 +0300 |
| commit | 7b68621f8d16689cbb4203aceaca86ffb165f1d0 (patch) | |
| tree | dfcd327cd822792877e2b007a9bc079d0ddd94fe /include/linux/trace_recursion.h | |
| parent | 60602cb549f1965a7edbc96026760dfb93911fab (diff) | |
| download | linux-7b68621f8d16689cbb4203aceaca86ffb165f1d0.tar.xz | |
ftrace: Clean up the recursion code a bit
In trace_test_and_set_recursion(), current->trace_recursion is placed into a
variable, and that variable should be used for the processing, as there's no
reason to dereference current multiple times.
On trace_clear_recursion(), current->trace_recursion is modified and there's
no reason to copy it over to a variable.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/trace_recursion.h')
| -rw-r--r-- | include/linux/trace_recursion.h | 22 |
1 files changed, 7 insertions, 15 deletions
diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h index 228cc56ed66e..a9f9c5714e65 100644 --- a/include/linux/trace_recursion.h +++ b/include/linux/trace_recursion.h @@ -162,7 +162,7 @@ extern void ftrace_record_recursion(unsigned long ip, unsigned long parent_ip); static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsigned long pip, int start, int max) { - unsigned int val = current->trace_recursion; + unsigned int val = READ_ONCE(current->trace_recursion); int bit; /* A previous recursion check was made */ @@ -176,18 +176,15 @@ static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsign * a switch between contexts. Allow for a single recursion. */ bit = TRACE_TRANSITION_BIT; - if (trace_recursion_test(bit)) { + if (val & (1 << bit)) { do_ftrace_record_recursion(ip, pip); return -1; } - trace_recursion_set(bit); - barrier(); - return bit + 1; + } else { + /* Normal check passed, clear the transition to allow it again */ + val &= ~(1 << TRACE_TRANSITION_BIT); } - /* Normal check passed, clear the transition to allow it again */ - trace_recursion_clear(TRACE_TRANSITION_BIT); - val |= 1 << bit; current->trace_recursion = val; barrier(); @@ -197,17 +194,12 @@ static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsign static __always_inline void trace_clear_recursion(int bit) { - unsigned int val = current->trace_recursion; - if (!bit) return; - bit--; - bit = 1 << bit; - val &= ~bit; - barrier(); - current->trace_recursion = val; + bit--; + trace_recursion_clear(bit); } /** |