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Subject[PATCH tracing/kprobes 3/7] tracing/kprobes: Cleanup kprobe tracer code.
Date
Simplify trace_probe to remove an union, and remove some redundant wrappers.
And also, cleanup create_trace_probe() function.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
---
kernel/trace/trace_kprobe.c | 81 ++++++++++++++++++-------------------------
1 files changed, 34 insertions(+), 47 deletions(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 8491525..902a148 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -180,10 +180,7 @@ static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)

struct trace_probe {
struct list_head list;
- union {
- struct kprobe kp;
- struct kretprobe rp;
- };
+ struct kretprobe rp; /* Use rp.kp for kprobe use */
unsigned long nhit;
const char *symbol; /* symbol name */
struct ftrace_event_call call;
@@ -202,7 +199,7 @@ static int kretprobe_trace_func(struct kretprobe_instance *ri,

static __kprobes int probe_is_return(struct trace_probe *tp)
{
- return (tp->rp.handler == kretprobe_trace_func);
+ return tp->rp.handler != NULL;
}

static __kprobes const char *probe_symbol(struct trace_probe *tp)
@@ -210,16 +207,6 @@ static __kprobes const char *probe_symbol(struct trace_probe *tp)
return tp->symbol ? tp->symbol : "unknown";
}

-static __kprobes unsigned int probe_offset(struct trace_probe *tp)
-{
- return (probe_is_return(tp)) ? tp->rp.kp.offset : tp->kp.offset;
-}
-
-static __kprobes void *probe_address(struct trace_probe *tp)
-{
- return (probe_is_return(tp)) ? tp->rp.kp.addr : tp->kp.addr;
-}
-
static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
{
int ret = -EINVAL;
@@ -269,8 +256,14 @@ static void unregister_probe_event(struct trace_probe *tp);
static DEFINE_MUTEX(probe_lock);
static LIST_HEAD(probe_list);

-static struct trace_probe *alloc_trace_probe(const char *symbol,
- const char *event, int nargs)
+/*
+ * Allocate new trace_probe and initialize it (including kprobes).
+ */
+static struct trace_probe *alloc_trace_probe(const char *event,
+ void *addr,
+ const char *symbol,
+ unsigned long offs,
+ int nargs, int is_return)
{
struct trace_probe *tp;

@@ -282,7 +275,16 @@ static struct trace_probe *alloc_trace_probe(const char *symbol,
tp->symbol = kstrdup(symbol, GFP_KERNEL);
if (!tp->symbol)
goto error;
- }
+ tp->rp.kp.symbol_name = tp->symbol;
+ tp->rp.kp.offset = offs;
+ } else
+ tp->rp.kp.addr = addr;
+
+ if (is_return)
+ tp->rp.handler = kretprobe_trace_func;
+ else
+ tp->rp.kp.pre_handler = kprobe_trace_func;
+
if (!event)
goto error;
tp->call.name = kstrdup(event, GFP_KERNEL);
@@ -327,7 +329,7 @@ static void __unregister_trace_probe(struct trace_probe *tp)
if (probe_is_return(tp))
unregister_kretprobe(&tp->rp);
else
- unregister_kprobe(&tp->kp);
+ unregister_kprobe(&tp->rp.kp);
}

/* Unregister a trace_probe and probe_event: call with locking probe_lock */
@@ -349,14 +351,14 @@ static int register_trace_probe(struct trace_probe *tp)
if (probe_is_return(tp))
ret = register_kretprobe(&tp->rp);
else
- ret = register_kprobe(&tp->kp);
+ ret = register_kprobe(&tp->rp.kp);

if (ret) {
pr_warning("Could not insert probe(%d)\n", ret);
if (ret == -EILSEQ) {
pr_warning("Probing address(0x%p) is not an "
"instruction boundary.\n",
- probe_address(tp));
+ tp->rp.kp.addr);
ret = -EINVAL;
}
goto end;
@@ -530,12 +532,12 @@ static int create_trace_probe(int argc, char **argv)
* +|-offs(ARG) : fetch memory at ARG +|- offs address.
*/
struct trace_probe *tp;
- struct kprobe *kp;
int i, ret = 0;
int is_return = 0;
char *symbol = NULL, *event = NULL;
unsigned long offset = 0;
void *addr = NULL;
+ char buf[MAX_EVENT_NAME_LEN];

if (argc < 2)
return -EINVAL;
@@ -577,33 +579,18 @@ static int create_trace_probe(int argc, char **argv)
/* setup a probe */
if (!event) {
/* Make a new event name */
- char buf[MAX_EVENT_NAME_LEN];
if (symbol)
snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
is_return ? 'r' : 'p', symbol, offset);
else
snprintf(buf, MAX_EVENT_NAME_LEN, "%c@0x%p",
is_return ? 'r' : 'p', addr);
- tp = alloc_trace_probe(symbol, buf, argc);
- } else
- tp = alloc_trace_probe(symbol, event, argc);
+ event = buf;
+ }
+ tp = alloc_trace_probe(event, addr, symbol, offset, argc, is_return);
if (IS_ERR(tp))
return PTR_ERR(tp);

- if (is_return) {
- kp = &tp->rp.kp;
- tp->rp.handler = kretprobe_trace_func;
- } else {
- kp = &tp->kp;
- tp->kp.pre_handler = kprobe_trace_func;
- }
-
- if (tp->symbol) {
- kp->symbol_name = tp->symbol;
- kp->offset = (unsigned int)offset;
- } else
- kp->addr = addr;
-
/* parse arguments */
ret = 0;
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
@@ -670,9 +657,9 @@ static int probes_seq_show(struct seq_file *m, void *v)
seq_printf(m, ":%s", tp->call.name);

if (tp->symbol)
- seq_printf(m, " %s+%u", probe_symbol(tp), probe_offset(tp));
+ seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
else
- seq_printf(m, " 0x%p", probe_address(tp));
+ seq_printf(m, " 0x%p", tp->rp.kp.addr);

for (i = 0; i < tp->nr_args; i++) {
ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i]);
@@ -783,7 +770,7 @@ static int probes_profile_seq_show(struct seq_file *m, void *v)
struct trace_probe *tp = v;

seq_printf(m, " %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
- probe_is_return(tp) ? tp->rp.kp.nmissed : tp->kp.nmissed);
+ tp->rp.kp.nmissed);

return 0;
}
@@ -811,7 +798,7 @@ static const struct file_operations kprobe_profile_ops = {
/* Kprobe handler */
static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
{
- struct trace_probe *tp = container_of(kp, struct trace_probe, kp);
+ struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
struct kprobe_trace_entry *entry;
struct ring_buffer_event *event;
int size, i, pc;
@@ -864,7 +851,7 @@ static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,

entry = ring_buffer_event_data(event);
entry->nargs = tp->nr_args;
- entry->func = (unsigned long)probe_address(tp);
+ entry->func = (unsigned long)tp->rp.kp.addr;
entry->ret_ip = (unsigned long)ri->ret_addr;
for (i = 0; i < tp->nr_args; i++)
entry->args[i] = call_fetch(&tp->args[i], regs);
@@ -943,7 +930,7 @@ static int probe_event_enable(struct ftrace_event_call *call)
if (probe_is_return(tp))
return enable_kretprobe(&tp->rp);
else
- return enable_kprobe(&tp->kp);
+ return enable_kprobe(&tp->rp.kp);
}

static void probe_event_disable(struct ftrace_event_call *call)
@@ -953,7 +940,7 @@ static void probe_event_disable(struct ftrace_event_call *call)
if (probe_is_return(tp))
disable_kretprobe(&tp->rp);
else
- disable_kprobe(&tp->kp);
+ disable_kprobe(&tp->rp.kp);
}

static int probe_event_raw_init(struct ftrace_event_call *event_call)

--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com


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