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crypto: caam - get rid of tasklet 

Threaded interrupts can perform the function of the tasklet, and much
more safely too - without races when trying to take the tasklet and
interrupt down on device removal.

With the old code, there is a window where we call tasklet_kill().  If
the interrupt handler happens to be running on a different CPU, and
subsequently calls tasklet_schedule(), the tasklet will be re-scheduled
for execution.

Switching to a hardirq/threadirq combination implementation avoids this,
and it also means generic code deals with the teardown sequencing of the
threaded and non-threaded parts.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Russell King 2016-08-08 18:05:24 +01:00 committed by Herbert Xu
parent 65cf164a4a
commit 66d2e20280
2 changed files with 9 additions and 17 deletions
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1
drivers/crypto/caam/intern.h
View File

@ -41,7 +41,6 @@ struct caam_drv_private_jr {
struct device *dev;
int ridx;
struct caam_job_ring __iomem *rregs; /* JobR's register space */
struct tasklet_struct irqtask;
int irq; /* One per queue */
/* Number of scatterlist crypt transforms active on the JobR */

25
drivers/crypto/caam/jr.c
View File

@ -73,8 +73,6 @@ static int caam_jr_shutdown(struct device *dev)
ret = caam_reset_hw_jr(dev);
tasklet_kill(&jrp->irqtask);
/* Release interrupt */
free_irq(jrp->irq, dev);
@ -130,7 +128,7 @@ static irqreturn_t caam_jr_interrupt(int irq, void *st_dev)
/*
* Check the output ring for ready responses, kick
* tasklet if jobs done.
* the threaded irq if jobs done.
*/
irqstate = rd_reg32(&jrp->rregs->jrintstatus);
if (!irqstate)
@ -152,18 +150,13 @@ static irqreturn_t caam_jr_interrupt(int irq, void *st_dev)
/* Have valid interrupt at this point, just ACK and trigger */
wr_reg32(&jrp->rregs->jrintstatus, irqstate);
preempt_disable();
tasklet_schedule(&jrp->irqtask);
preempt_enable();
return IRQ_HANDLED;
return IRQ_WAKE_THREAD;
}
/* Deferred service handler, run as interrupt-fired tasklet */
static void caam_jr_dequeue(unsigned long devarg)
static irqreturn_t caam_jr_threadirq(int irq, void *st_dev)
{
int hw_idx, sw_idx, i, head, tail;
struct device *dev = (struct device *)devarg;
struct device *dev = st_dev;
struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
void (*usercall)(struct device *dev, u32 *desc, u32 status, void *arg);
u32 *userdesc, userstatus;
@ -237,6 +230,8 @@ static void caam_jr_dequeue(unsigned long devarg)
/* reenable / unmask IRQs */
clrsetbits_32(&jrp->rregs->rconfig_lo, JRCFG_IMSK, 0);
return IRQ_HANDLED;
}
/**
@ -394,11 +389,10 @@ static int caam_jr_init(struct device *dev)
jrp = dev_get_drvdata(dev);
tasklet_init(&jrp->irqtask, caam_jr_dequeue, (unsigned long)dev);
/* Connect job ring interrupt handler. */
error = request_irq(jrp->irq, caam_jr_interrupt, IRQF_SHARED,
dev_name(dev), dev);
error = request_threaded_irq(jrp->irq, caam_jr_interrupt,
caam_jr_threadirq, IRQF_SHARED,
dev_name(dev), dev);
if (error) {
dev_err(dev, "can't connect JobR %d interrupt (%d)\n",
jrp->ridx, jrp->irq);
@ -460,7 +454,6 @@ static int caam_jr_init(struct device *dev)
out_free_irq:
free_irq(jrp->irq, dev);
out_kill_deq:
tasklet_kill(&jrp->irqtask);
return error;
}