[patch 153/166] kcov: move t->kcov assignments into kcov_start/stop

Andrew Morton
2020-04-07T03:12:14Z

From: Andrey Konovalov <andreyknvl@google.com>
Subject: kcov: move t->kcov assignments into kcov_start/stop

Every time kcov_start/stop() is called, t->kcov is also assigned, so move
the assignment into the functions.

Link: http://lkml.kernel.org/r/6644839d3567df61ade3c4b246a46cacbe4f9e11.1585233617.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/82625ef3ff878f0b585763cc31d09d9b08ca37d6.1584655448.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

kernel/kcov.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

--- a/kernel/kcov.c~kcov-move-t-kcov-assignments-into-kcov_start-stop
+++ a/kernel/kcov.c
@@ -309,10 +309,12 @@ void notrace __sanitizer_cov_trace_switc
EXPORT_SYMBOL(__sanitizer_cov_trace_switch);
#endif /* ifdef CONFIG_KCOV_ENABLE_COMPARISONS */

-static void kcov_start(struct task_struct *t, unsigned int size,
- void *area, enum kcov_mode mode, int sequence)
+static void kcov_start(struct task_struct *t, struct kcov *kcov,
+ unsigned int size, void *area, enum kcov_mode mode,
+ int sequence)
{
kcov_debug("t = %px, size = %u, area = %px\n", t, size, area);
+ t->kcov = kcov;
/* Cache in task struct for performance. */
t->kcov_size = size;
t->kcov_area = area;
@@ -326,6 +328,7 @@ static void kcov_stop(struct task_struct
{
WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED);
barrier();
+ t->kcov = NULL;
t->kcov_size = 0;
t->kcov_area = NULL;
}
@@ -333,7 +336,6 @@ static void kcov_stop(struct task_struct
static void kcov_task_reset(struct task_struct *t)
{
kcov_stop(t);
- t->kcov = NULL;
t->kcov_sequence = 0;
t->kcov_handle = 0;
}
@@ -584,9 +586,8 @@ static int kcov_ioctl_locked(struct kcov
return mode;
kcov_fault_in_area(kcov);
kcov->mode = mode;
- kcov_start(t, kcov->size, kcov->area, kcov->mode,
+ kcov_start(t, kcov, kcov->size, kcov->area, kcov->mode,
kcov->sequence);
- t->kcov = kcov;
kcov->t = t;
/* Put either in kcov_task_exit() or in KCOV_DISABLE. */
kcov_get(kcov);
@@ -778,7 +779,6 @@ void kcov_remote_start(u64 handle)
kcov = remote->kcov;
/* Put in kcov_remote_stop(). */
kcov_get(kcov);
- t->kcov = kcov;
/*
* Read kcov fields before unlock to prevent races with
* KCOV_DISABLE / kcov_remote_reset().
@@ -792,7 +792,6 @@ void kcov_remote_start(u64 handle)
if (!area) {
area = vmalloc(size * sizeof(unsigned long));
if (!area) {
- t->kcov = NULL;
kcov_put(kcov);
return;
}
@@ -800,7 +799,7 @@ void kcov_remote_start(u64 handle)
/* Reset coverage size. */
*(u64 *)area = 0;

- kcov_start(t, size, area, mode, sequence);
+ kcov_start(t, kcov, size, area, mode, sequence);

}
EXPORT_SYMBOL(kcov_remote_start);
@@ -873,7 +872,6 @@ void kcov_remote_stop(void)
return;

kcov_stop(t);
- t->kcov = NULL;

spin_lock(&kcov->lock);
/*
_