Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S946404AbcJaUSx (ORCPT ); Mon, 31 Oct 2016 16:18:53 -0400 Received: from ns.gsystem.sk ([62.176.172.50]:36102 "EHLO gsystem.sk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S946322AbcJaUSt (ORCPT ); Mon, 31 Oct 2016 16:18:49 -0400 From: Ondrej Zary To: Christoph Hellwig Cc: Finn Thain , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/6] g_NCR5380: Test the IRQ before accepting it Date: Mon, 31 Oct 2016 21:18:28 +0100 Message-Id: <1477945112-25659-3-git-send-email-linux@rainbow-software.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1477945112-25659-1-git-send-email-linux@rainbow-software.org> References: <1477945112-25659-1-git-send-email-linux@rainbow-software.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2249 Lines: 74 Trigger an IRQ first with a test IRQ handler to find out if it really works. Disable the IRQ if not. This prevents hang when incorrect IRQ was specified by user. Signed-off-by: Ondrej Zary --- drivers/scsi/g_NCR5380.c | 44 +++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 41 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c index 09c660b..0d1f6ad 100644 --- a/drivers/scsi/g_NCR5380.c +++ b/drivers/scsi/g_NCR5380.c @@ -115,6 +115,32 @@ static int NCR5380_probe_irq(struct Scsi_Host *instance) return irq; } +static bool irq_working; + +static irqreturn_t test_irq(int irq, void *dev_id) +{ + irq_working = true; + return IRQ_HANDLED; +} + +/* test if the IRQ is working */ +static int NCR5380_test_irq(struct Scsi_Host *instance, int irq) +{ + struct NCR5380_hostdata *hostdata = shost_priv(instance); + + irq_working = false; + if (request_irq(irq, test_irq, 0, "NCR5380-irqtest", NULL)) + return -EBUSY; + NCR5380_trigger_irq(instance); + NCR5380_read(RESET_PARITY_INTERRUPT_REG); + free_irq(irq, NULL); + + if (!irq_working) + return -EIO; + + return 0; +} + /* * Configure I/O address of 53C400A or DTC436 by writing magic numbers * to ports 0x779 and 0x379. @@ -323,9 +349,21 @@ static int generic_NCR5380_init_one(struct scsi_host_template *tpnt, /* set IRQ for HP C2502 */ if (board == BOARD_HP_C2502) magic_configure(port_idx, instance->irq, magic); - if (request_irq(instance->irq, generic_NCR5380_intr, - 0, "NCR5380", instance)) { - printk(KERN_WARNING "scsi%d : IRQ%d not free, interrupts disabled\n", instance->host_no, instance->irq); + ret = NCR5380_test_irq(instance, instance->irq); + if (ret) { + printk(KERN_WARNING "scsi%d : IRQ%d not %s, interrupts disabled\n", + instance->host_no, instance->irq, + (ret == -EBUSY) ? "free" : "working"); + instance->irq = NO_IRQ; + } + } + + if (instance->irq != NO_IRQ) { + if (request_irq(instance->irq, generic_NCR5380_intr, 0, + "NCR5380", instance)) { + printk(KERN_WARNING "scsi%d : IRQ%d not free, interrupts disabled\n", + instance->host_no, + instance->irq); instance->irq = NO_IRQ; } } -- Ondrej Zary