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Commit 66d2e202 authored by Russell King's avatar Russell King Committed by Herbert Xu
Browse files

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: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 65cf164a

drivers/crypto/caam/intern.h

+0 −1
Original line number Diff line number Diff line
@@ -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 */

drivers/crypto/caam/jr.c

+9 −16
Original line number Diff line number Diff line
@@ -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;

}



/**
@@ -394,10 +389,9 @@ 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,

	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",
@@ -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;

}