| Message ID | 20170315174654.15128-3-john@metanate.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hello John- On Wed, Mar 15, 2017 at 05:46:52PM +0000, John Keeping wrote: > This lock is used from rockchip_irq_set_type() which is part of the > irq_chip implementation and thus must use raw_spinlock_t as documented > in Documentation/gpio/driver.txt. > > Signed-off-by: John Keeping <john@metanate.com> > Reviewed-by: Heiko Stuebner <heiko@sntech.de> > Tested-by: Heiko Stuebner <heiko@sntech.de> > --- > v2: unchanged > --- > drivers/pinctrl/pinctrl-rockchip.c | 30 +++++++++++++++--------------- > 1 file changed, 15 insertions(+), 15 deletions(-) > > diff --git a/drivers/pinctrl/pinctrl-rockchip.c b/drivers/pinctrl/pinctrl-rockchip.c > index 128c383ea7ba..8c1cae6d78d7 100644 > --- a/drivers/pinctrl/pinctrl-rockchip.c > +++ b/drivers/pinctrl/pinctrl-rockchip.c > @@ -163,7 +163,7 @@ struct rockchip_pin_bank { > struct irq_domain *domain; > struct gpio_chip gpio_chip; > struct pinctrl_gpio_range grange; > - spinlock_t slock; > + raw_spinlock_t slock; > u32 toggle_edge_mode; > }; > > @@ -1295,14 +1295,14 @@ static int rockchip_set_pull(struct rockchip_pin_bank *bank, > > switch (ctrl->type) { > case RK2928: > - spin_lock_irqsave(&bank->slock, flags); > + raw_spin_lock_irqsave(&bank->slock, flags); > > data = BIT(bit + 16); > if (pull == PIN_CONFIG_BIAS_DISABLE) > data |= BIT(bit); This should be lifted out from under the lock. > ret = regmap_write(regmap, reg, data); How is this legal? The regmap_write() here is going to end up acquiring the regmap mutex. Julia
On Wed, 15 Mar 2017 13:01:37 -0500, Julia Cartwright wrote: > On Wed, Mar 15, 2017 at 05:46:52PM +0000, John Keeping wrote: > > This lock is used from rockchip_irq_set_type() which is part of the > > irq_chip implementation and thus must use raw_spinlock_t as documented > > in Documentation/gpio/driver.txt. > > > > Signed-off-by: John Keeping <john@metanate.com> > > Reviewed-by: Heiko Stuebner <heiko@sntech.de> > > Tested-by: Heiko Stuebner <heiko@sntech.de> > > --- > > v2: unchanged > > --- > > drivers/pinctrl/pinctrl-rockchip.c | 30 +++++++++++++++--------------- > > 1 file changed, 15 insertions(+), 15 deletions(-) > > > > diff --git a/drivers/pinctrl/pinctrl-rockchip.c b/drivers/pinctrl/pinctrl-rockchip.c > > index 128c383ea7ba..8c1cae6d78d7 100644 > > --- a/drivers/pinctrl/pinctrl-rockchip.c > > +++ b/drivers/pinctrl/pinctrl-rockchip.c > > @@ -163,7 +163,7 @@ struct rockchip_pin_bank { > > struct irq_domain *domain; > > struct gpio_chip gpio_chip; > > struct pinctrl_gpio_range grange; > > - spinlock_t slock; > > + raw_spinlock_t slock; > > u32 toggle_edge_mode; > > }; > > > > @@ -1295,14 +1295,14 @@ static int rockchip_set_pull(struct rockchip_pin_bank *bank, > > > > switch (ctrl->type) { > > case RK2928: > > - spin_lock_irqsave(&bank->slock, flags); > > + raw_spin_lock_irqsave(&bank->slock, flags); > > > > data = BIT(bit + 16); > > if (pull == PIN_CONFIG_BIAS_DISABLE) > > data |= BIT(bit); > > This should be lifted out from under the lock. > > > ret = regmap_write(regmap, reg, data); > > How is this legal? The regmap_write() here is going to end up acquiring > the regmap mutex. It's not, the spinlock can be deleted here. I only have RK3288 hardware to test and I missed this when checking the uses of slock. John
Am Mittwoch, 15. März 2017, 18:08:06 CET schrieb John Keeping: > On Wed, 15 Mar 2017 13:01:37 -0500, Julia Cartwright wrote: > > On Wed, Mar 15, 2017 at 05:46:52PM +0000, John Keeping wrote: > > > This lock is used from rockchip_irq_set_type() which is part of the > > > irq_chip implementation and thus must use raw_spinlock_t as documented > > > in Documentation/gpio/driver.txt. > > > > > > Signed-off-by: John Keeping <john@metanate.com> > > > Reviewed-by: Heiko Stuebner <heiko@sntech.de> > > > Tested-by: Heiko Stuebner <heiko@sntech.de> > > > --- > > > v2: unchanged > > > --- > > > > > > drivers/pinctrl/pinctrl-rockchip.c | 30 +++++++++++++++--------------- > > > 1 file changed, 15 insertions(+), 15 deletions(-) > > > > > > diff --git a/drivers/pinctrl/pinctrl-rockchip.c > > > b/drivers/pinctrl/pinctrl-rockchip.c index 128c383ea7ba..8c1cae6d78d7 > > > 100644 > > > --- a/drivers/pinctrl/pinctrl-rockchip.c > > > +++ b/drivers/pinctrl/pinctrl-rockchip.c > > > @@ -163,7 +163,7 @@ struct rockchip_pin_bank { > > > > > > struct irq_domain *domain; > > > struct gpio_chip gpio_chip; > > > struct pinctrl_gpio_range grange; > > > > > > - spinlock_t slock; > > > + raw_spinlock_t slock; > > > > > > u32 toggle_edge_mode; > > > > > > }; > > > > > > @@ -1295,14 +1295,14 @@ static int rockchip_set_pull(struct > > > rockchip_pin_bank *bank,> > > > > switch (ctrl->type) { > > > > > > case RK2928: > > > - spin_lock_irqsave(&bank->slock, flags); > > > + raw_spin_lock_irqsave(&bank->slock, flags); > > > > > > data = BIT(bit + 16); > > > if (pull == PIN_CONFIG_BIAS_DISABLE) > > > > > > data |= BIT(bit); > > > > This should be lifted out from under the lock. > > > > > ret = regmap_write(regmap, reg, data); > > > > How is this legal? The regmap_write() here is going to end up acquiring > > the regmap mutex. > > It's not, the spinlock can be deleted here. I only have RK3288 hardware > to test and I missed this when checking the uses of slock. That part could very well also use regmap_update_bits like the other parts. Not really sure, why we use regmap_write here, but I'm also not sure, if it matters at all.
On Wed, Mar 15, 2017 at 07:16:53PM +0100, Heiko Stuebner wrote: > Am Mittwoch, 15. März 2017, 18:08:06 CET schrieb John Keeping: > > On Wed, 15 Mar 2017 13:01:37 -0500, Julia Cartwright wrote: > > > On Wed, Mar 15, 2017 at 05:46:52PM +0000, John Keeping wrote: > > > > This lock is used from rockchip_irq_set_type() which is part of the > > > > irq_chip implementation and thus must use raw_spinlock_t as documented > > > > in Documentation/gpio/driver.txt. > > > > > > > > Signed-off-by: John Keeping <john@metanate.com> > > > > Reviewed-by: Heiko Stuebner <heiko@sntech.de> > > > > Tested-by: Heiko Stuebner <heiko@sntech.de> > > > > --- > > > > v2: unchanged > > > > --- > > > > > > > > drivers/pinctrl/pinctrl-rockchip.c | 30 +++++++++++++++--------------- > > > > 1 file changed, 15 insertions(+), 15 deletions(-) > > > > > > > > diff --git a/drivers/pinctrl/pinctrl-rockchip.c > > > > b/drivers/pinctrl/pinctrl-rockchip.c index 128c383ea7ba..8c1cae6d78d7 > > > > 100644 [..] > > > > @@ -1295,14 +1295,14 @@ static int rockchip_set_pull(struct > > > > rockchip_pin_bank *bank,> > > > > > switch (ctrl->type) { > > > > > > > > case RK2928: > > > > - spin_lock_irqsave(&bank->slock, flags); > > > > + raw_spin_lock_irqsave(&bank->slock, flags); > > > > > > > > data = BIT(bit + 16); > > > > if (pull == PIN_CONFIG_BIAS_DISABLE) > > > > > > > > data |= BIT(bit); > > > > > > This should be lifted out from under the lock. > > > > > > > ret = regmap_write(regmap, reg, data); > > > > > > How is this legal? The regmap_write() here is going to end up acquiring > > > the regmap mutex. > > > > It's not, the spinlock can be deleted here. I only have RK3288 hardware > > to test and I missed this when checking the uses of slock. > > That part could very well also use regmap_update_bits like the other parts. > Not really sure, why we use regmap_write here, but I'm also not sure, if it > matters at all. regmap_update_bits also acquires the regmap lock, which would similarly be a problem here.[1] But, if we could pull this entire operation out of the lock (and convince ourselves that it's okay to do so), then even better! Julia 1: Why is this a problem? Because we're in the middle of a raw_spinlock_t protected critical region: if there were contention on the nested mutex (the "regmap mutex"), then we'd attempt to sleep in atomic context.
On Wed, 15 Mar 2017 13:23:09 -0500, Julia Cartwright wrote: > On Wed, Mar 15, 2017 at 07:16:53PM +0100, Heiko Stuebner wrote: > > Am Mittwoch, 15. März 2017, 18:08:06 CET schrieb John Keeping: > > > On Wed, 15 Mar 2017 13:01:37 -0500, Julia Cartwright wrote: > > > > On Wed, Mar 15, 2017 at 05:46:52PM +0000, John Keeping wrote: > > > > > This lock is used from rockchip_irq_set_type() which is part of the > > > > > irq_chip implementation and thus must use raw_spinlock_t as documented > > > > > in Documentation/gpio/driver.txt. > > > > > > > > > > Signed-off-by: John Keeping <john@metanate.com> > > > > > Reviewed-by: Heiko Stuebner <heiko@sntech.de> > > > > > Tested-by: Heiko Stuebner <heiko@sntech.de> > > > > > --- > > > > > v2: unchanged > > > > > --- > > > > > > > > > > drivers/pinctrl/pinctrl-rockchip.c | 30 +++++++++++++++--------------- > > > > > 1 file changed, 15 insertions(+), 15 deletions(-) > > > > > > > > > > diff --git a/drivers/pinctrl/pinctrl-rockchip.c > > > > > b/drivers/pinctrl/pinctrl-rockchip.c index 128c383ea7ba..8c1cae6d78d7 > > > > > 100644 > [..] > > > > > @@ -1295,14 +1295,14 @@ static int rockchip_set_pull(struct > > > > > rockchip_pin_bank *bank,> > > > > > > switch (ctrl->type) { > > > > > > > > > > case RK2928: > > > > > - spin_lock_irqsave(&bank->slock, flags); > > > > > + raw_spin_lock_irqsave(&bank->slock, flags); > > > > > > > > > > data = BIT(bit + 16); > > > > > if (pull == PIN_CONFIG_BIAS_DISABLE) > > > > > > > > > > data |= BIT(bit); > > > > > > > > This should be lifted out from under the lock. > > > > > > > > > ret = regmap_write(regmap, reg, data); > > > > > > > > How is this legal? The regmap_write() here is going to end up acquiring > > > > the regmap mutex. > > > > > > It's not, the spinlock can be deleted here. I only have RK3288 hardware > > > to test and I missed this when checking the uses of slock. > > > > That part could very well also use regmap_update_bits like the other parts. > > Not really sure, why we use regmap_write here, but I'm also not sure, if it > > matters at all. > > regmap_update_bits also acquires the regmap lock, which would similarly > be a problem here.[1] > > But, if we could pull this entire operation out of the lock (and > convince ourselves that it's okay to do so), then even better! Yes, we can delete the lock here for the same reason as all of the others that are removed in patch 1. I don't think it makes much difference whether we use regmap_write or regmap_update_bits here (although consistently using regmap_update_bits might be nice) so I won't change it as part of this series, especially since I don't have an RK2928 to test. John
diff --git a/drivers/pinctrl/pinctrl-rockchip.c b/drivers/pinctrl/pinctrl-rockchip.c index 128c383ea7ba..8c1cae6d78d7 100644 --- a/drivers/pinctrl/pinctrl-rockchip.c +++ b/drivers/pinctrl/pinctrl-rockchip.c @@ -163,7 +163,7 @@ struct rockchip_pin_bank { struct irq_domain *domain; struct gpio_chip gpio_chip; struct pinctrl_gpio_range grange; - spinlock_t slock; + raw_spinlock_t slock; u32 toggle_edge_mode; }; @@ -1295,14 +1295,14 @@ static int rockchip_set_pull(struct rockchip_pin_bank *bank, switch (ctrl->type) { case RK2928: - spin_lock_irqsave(&bank->slock, flags); + raw_spin_lock_irqsave(&bank->slock, flags); data = BIT(bit + 16); if (pull == PIN_CONFIG_BIAS_DISABLE) data |= BIT(bit); ret = regmap_write(regmap, reg, data); - spin_unlock_irqrestore(&bank->slock, flags); + raw_spin_unlock_irqrestore(&bank->slock, flags); break; case RK1108: case RK3188: @@ -1503,7 +1503,7 @@ static int _rockchip_pmx_gpio_set_direction(struct gpio_chip *chip, return ret; clk_enable(bank->clk); - spin_lock_irqsave(&bank->slock, flags); + raw_spin_lock_irqsave(&bank->slock, flags); data = readl_relaxed(bank->reg_base + GPIO_SWPORT_DDR); /* set bit to 1 for output, 0 for input */ @@ -1513,7 +1513,7 @@ static int _rockchip_pmx_gpio_set_direction(struct gpio_chip *chip, data &= ~BIT(pin); writel_relaxed(data, bank->reg_base + GPIO_SWPORT_DDR); - spin_unlock_irqrestore(&bank->slock, flags); + raw_spin_unlock_irqrestore(&bank->slock, flags); clk_disable(bank->clk); return 0; @@ -1963,7 +1963,7 @@ static void rockchip_gpio_set(struct gpio_chip *gc, unsigned offset, int value) u32 data; clk_enable(bank->clk); - spin_lock_irqsave(&bank->slock, flags); + raw_spin_lock_irqsave(&bank->slock, flags); data = readl(reg); data &= ~BIT(offset); @@ -1971,7 +1971,7 @@ static void rockchip_gpio_set(struct gpio_chip *gc, unsigned offset, int value) data |= BIT(offset); writel(data, reg); - spin_unlock_irqrestore(&bank->slock, flags); + raw_spin_unlock_irqrestore(&bank->slock, flags); clk_disable(bank->clk); } @@ -2083,7 +2083,7 @@ static void rockchip_irq_demux(struct irq_desc *desc) data = readl_relaxed(bank->reg_base + GPIO_EXT_PORT); do { - spin_lock_irqsave(&bank->slock, flags); + raw_spin_lock_irqsave(&bank->slock, flags); polarity = readl_relaxed(bank->reg_base + GPIO_INT_POLARITY); @@ -2094,7 +2094,7 @@ static void rockchip_irq_demux(struct irq_desc *desc) writel(polarity, bank->reg_base + GPIO_INT_POLARITY); - spin_unlock_irqrestore(&bank->slock, flags); + raw_spin_unlock_irqrestore(&bank->slock, flags); data_old = data; data = readl_relaxed(bank->reg_base + @@ -2125,20 +2125,20 @@ static int rockchip_irq_set_type(struct irq_data *d, unsigned int type) return ret; clk_enable(bank->clk); - spin_lock_irqsave(&bank->slock, flags); + raw_spin_lock_irqsave(&bank->slock, flags); data = readl_relaxed(bank->reg_base + GPIO_SWPORT_DDR); data &= ~mask; writel_relaxed(data, bank->reg_base + GPIO_SWPORT_DDR); - spin_unlock_irqrestore(&bank->slock, flags); + raw_spin_unlock_irqrestore(&bank->slock, flags); if (type & IRQ_TYPE_EDGE_BOTH) irq_set_handler_locked(d, handle_edge_irq); else irq_set_handler_locked(d, handle_level_irq); - spin_lock_irqsave(&bank->slock, flags); + raw_spin_lock_irqsave(&bank->slock, flags); irq_gc_lock(gc); level = readl_relaxed(gc->reg_base + GPIO_INTTYPE_LEVEL); @@ -2181,7 +2181,7 @@ static int rockchip_irq_set_type(struct irq_data *d, unsigned int type) break; default: irq_gc_unlock(gc); - spin_unlock_irqrestore(&bank->slock, flags); + raw_spin_unlock_irqrestore(&bank->slock, flags); clk_disable(bank->clk); return -EINVAL; } @@ -2190,7 +2190,7 @@ static int rockchip_irq_set_type(struct irq_data *d, unsigned int type) writel_relaxed(polarity, gc->reg_base + GPIO_INT_POLARITY); irq_gc_unlock(gc); - spin_unlock_irqrestore(&bank->slock, flags); + raw_spin_unlock_irqrestore(&bank->slock, flags); clk_disable(bank->clk); return 0; @@ -2472,7 +2472,7 @@ static struct rockchip_pin_ctrl *rockchip_pinctrl_get_soc_data( for (i = 0; i < ctrl->nr_banks; ++i, ++bank) { int bank_pins = 0; - spin_lock_init(&bank->slock); + raw_spin_lock_init(&bank->slock); bank->drvdata = d; bank->pin_base = ctrl->nr_pins; ctrl->nr_pins += bank->nr_pins;