From: Russell King Subject: [PATCH RFC 11/11] crypto: caam: get rid of tasklet Date: Mon, 07 Dec 2015 19:12:51 +0000 Message-ID: References: <20151207191134.GV8644@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Cc: "David S. Miller" , linux-crypto@vger.kernel.org To: Fabio Estevam , Herbert Xu Return-path: Received: from pandora.arm.linux.org.uk ([78.32.30.218]:60545 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932307AbbLGTM4 (ORCPT ); Mon, 7 Dec 2015 14:12:56 -0500 In-Reply-To: <20151207191134.GV8644@n2100.arm.linux.org.uk> Content-Disposition: inline Sender: linux-crypto-owner@vger.kernel.org List-ID: 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 --- drivers/crypto/caam/intern.h | 1 - drivers/crypto/caam/jr.c | 25 +++++++++---------------- 2 files changed, 9 insertions(+), 17 deletions(-) diff --git a/drivers/crypto/caam/intern.h b/drivers/crypto/caam/intern.h index e2bcacc1a921..5d4c05074a5c 100644 --- a/drivers/crypto/caam/intern.h +++ b/drivers/crypto/caam/intern.h @@ -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 */ diff --git a/drivers/crypto/caam/jr.c b/drivers/crypto/caam/jr.c index f7e0d8d4c3da..b77ee2b88f37 100644 --- a/drivers/crypto/caam/jr.c +++ b/drivers/crypto/caam/jr.c @@ -73,8 +73,6 @@ 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 */ clrbits32(&jrp->rregs->rconfig_lo, JRCFG_IMSK); + + 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; } -- 2.1.0