[PATCH] atm: idt77252: Convert timers to use timer_setup()

From: Kees Cook
Date: Wed Oct 04 2017 - 20:51:25 EST


In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly. This required adding a pointer back
to vc_map, and adjusting the locking around removal a bit.

Cc: Chas Williams <3chas3@xxxxxxxxx>
Cc: linux-atm-general@xxxxxxxxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
This requires commit 686fef928bba ("timer: Prepare to change timer
callback argument type") in v4.14-rc3, but should be otherwise
stand-alone.
---
drivers/atm/idt77252.c | 21 ++++++++++++---------
drivers/atm/idt77252.h | 3 +++
2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/atm/idt77252.c b/drivers/atm/idt77252.c
index 47f3c4ae0594..0e3b9c44c808 100644
--- a/drivers/atm/idt77252.c
+++ b/drivers/atm/idt77252.c
@@ -2073,21 +2073,19 @@ idt77252_rate_logindex(struct idt77252_dev *card, int pcr)
}

static void
-idt77252_est_timer(unsigned long data)
+idt77252_est_timer(struct timer_list *t)
{
- struct vc_map *vc = (struct vc_map *)data;
+ struct rate_estimator *est = from_timer(est, t, timer);
+ struct vc_map *vc = est->vc;
struct idt77252_dev *card = vc->card;
- struct rate_estimator *est;
unsigned long flags;
u32 rate, cps;
u64 ncells;
u8 lacr;

spin_lock_irqsave(&vc->lock, flags);
- est = vc->estimator;
- if (!est)
+ if (!vc->estimator)
goto out;
-
ncells = est->cells;

rate = ((u32)(ncells - est->last_cells)) << (7 - est->interval);
@@ -2126,10 +2124,11 @@ idt77252_init_est(struct vc_map *vc, int pcr)
est->maxcps = pcr < 0 ? -pcr : pcr;
est->cps = est->maxcps;
est->avcps = est->cps << 5;
+ est->vc = vc;

est->interval = 2; /* XXX: make this configurable */
est->ewma_log = 2; /* XXX: make this configurable */
- setup_timer(&est->timer, idt77252_est_timer, (unsigned long)vc);
+ timer_setup(&est->timer, idt77252_est_timer, 0);
mod_timer(&est->timer, jiffies + ((HZ / 4) << est->interval));

return est;
@@ -2209,16 +2208,20 @@ static int
idt77252_init_ubr(struct idt77252_dev *card, struct vc_map *vc,
struct atm_vcc *vcc, struct atm_qos *qos)
{
+ struct rate_estimator *est = NULL;
unsigned long flags;
int tcr;

spin_lock_irqsave(&vc->lock, flags);
if (vc->estimator) {
- del_timer(&vc->estimator->timer);
- kfree(vc->estimator);
+ est = vc->estimator;
vc->estimator = NULL;
}
spin_unlock_irqrestore(&vc->lock, flags);
+ if (est) {
+ del_timer_sync(&est->timer);
+ kfree(est);
+ }

tcr = atm_pcr_goal(&qos->txtp);
if (tcr == 0)
diff --git a/drivers/atm/idt77252.h b/drivers/atm/idt77252.h
index 3a82cc23a053..9339197d701c 100644
--- a/drivers/atm/idt77252.h
+++ b/drivers/atm/idt77252.h
@@ -184,6 +184,8 @@ struct aal1 {
unsigned char sequence;
};

+struct vc_map;
+
struct rate_estimator {
struct timer_list timer;
unsigned int interval;
@@ -193,6 +195,7 @@ struct rate_estimator {
long avcps;
u32 cps;
u32 maxcps;
+ struct vc_map *vc;
};

struct vc_map {
--
2.7.4


--
Kees Cook
Pixel Security