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kcsan: Simplify constant string handling

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Simplify checking prefixes and length calculation of constant strings.
For the former, the kernel provides str_has_prefix(), and the latter we
should just use strlen("..") because GCC and Clang have optimizations
that optimize these into constants.

No functional change intended.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Marco Elver 2020-07-31 10:17:20 +02:00 committed by Paul E. McKenney
parent 69b2c81bc8
commit a4e74fa5f0
2 changed files with 6 additions and 6 deletions
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8
kernel/kcsan/debugfs.c
View file

@ -300,16 +300,16 @@ debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *o
WRITE_ONCE(kcsan_enabled, true);
} else if (!strcmp(arg, "off")) {
WRITE_ONCE(kcsan_enabled, false);
} else if (!strncmp(arg, "microbench=", sizeof("microbench=") - 1)) {
} else if (str_has_prefix(arg, "microbench=")) {
unsigned long iters;
if (kstrtoul(&arg[sizeof("microbench=") - 1], 0, &iters))
if (kstrtoul(&arg[strlen("microbench=")], 0, &iters))
return -EINVAL;
microbenchmark(iters);
} else if (!strncmp(arg, "test=", sizeof("test=") - 1)) {
} else if (str_has_prefix(arg, "test=")) {
unsigned long iters;
if (kstrtoul(&arg[sizeof("test=") - 1], 0, &iters))
if (kstrtoul(&arg[strlen("test=")], 0, &iters))
return -EINVAL;
test_thread(iters);
} else if (!strcmp(arg, "whitelist")) {

4
kernel/kcsan/report.c
View file

@ -279,8 +279,8 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries
cur = strnstr(buf, "kcsan_", len);
if (cur) {
cur += sizeof("kcsan_") - 1;
if (strncmp(cur, "test", sizeof("test") - 1))
cur += strlen("kcsan_");
if (!str_has_prefix(cur, "test"))
continue; /* KCSAN runtime function. */
/* KCSAN related test. */
}