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Subject[for-next][PATCH 04/20] ftrace/x86: Have ftrace_write() return -EPERM and clean up callers
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Having ftrace_write() return -EPERM on failure, as that's what the callers
return, then we can clean up the code a bit. That is, instead of:

if (ftrace_write(...))
return -EPERM;
return 0;

or

if (ftrace_write(...)) {
ret = -EPERM;
goto_out;
}

We can instead have:

return ftrace_write(...);

or

ret = ftrace_write(...);
if (ret)
goto out;

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
arch/x86/kernel/ftrace.c | 27 ++++++++-------------------
1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 69885e2..8cabf63 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -308,7 +308,10 @@ static int ftrace_write(unsigned long ip, const char *val, int size)
if (within(ip, (unsigned long)_text, (unsigned long)_etext))
ip = (unsigned long)__va(__pa_symbol(ip));

- return probe_kernel_write((void *)ip, val, size);
+ if (probe_kernel_write((void *)ip, val, size))
+ return -EPERM;
+
+ return 0;
}

static int add_break(unsigned long ip, const char *old)
@@ -323,10 +326,7 @@ static int add_break(unsigned long ip, const char *old)
if (memcmp(replaced, old, MCOUNT_INSN_SIZE) != 0)
return -EINVAL;

- if (ftrace_write(ip, &brk, 1))
- return -EPERM;
-
- return 0;
+ return ftrace_write(ip, &brk, 1);
}

static int add_brk_on_call(struct dyn_ftrace *rec, unsigned long addr)
@@ -463,9 +463,7 @@ static int add_update_code(unsigned long ip, unsigned const char *new)
/* skip breakpoint */
ip++;
new++;
- if (ftrace_write(ip, new, MCOUNT_INSN_SIZE - 1))
- return -EPERM;
- return 0;
+ return ftrace_write(ip, new, MCOUNT_INSN_SIZE - 1);
}

static int add_update_call(struct dyn_ftrace *rec, unsigned long addr)
@@ -520,10 +518,7 @@ static int finish_update_call(struct dyn_ftrace *rec, unsigned long addr)

new = ftrace_call_replace(ip, addr);

- if (ftrace_write(ip, new, 1))
- return -EPERM;
-
- return 0;
+ return ftrace_write(ip, new, 1);
}

static int finish_update_nop(struct dyn_ftrace *rec)
@@ -533,9 +528,7 @@ static int finish_update_nop(struct dyn_ftrace *rec)

new = ftrace_nop_replace();

- if (ftrace_write(ip, new, 1))
- return -EPERM;
- return 0;
+ return ftrace_write(ip, new, 1);
}

static int finish_update(struct dyn_ftrace *rec, int enable)
@@ -656,10 +649,6 @@ ftrace_modify_code(unsigned long ip, unsigned const char *old_code,
run_sync();

ret = ftrace_write(ip, new_code, 1);
- if (ret) {
- ret = -EPERM;
- goto out;
- }
out:
run_sync();
return ret;
--
1.8.5.3



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