From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933849AbcHDOR5 (ORCPT ); Thu, 4 Aug 2016 10:17:57 -0400 Received: from relay1.mentorg.com ([192.94.38.131]:64532 "EHLO relay1.mentorg.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758241AbcHDORz (ORCPT ); Thu, 4 Aug 2016 10:17:55 -0400 From: Sandeep Jain To: , CC: , , Vladimir Zapolskiy , Sandeep Jain Subject: [PATCH v1 1/2] mtd: m25p80: lock module while used Date: Thu, 4 Aug 2016 19:46:33 +0530 Message-ID: <1470320194-9602-2-git-send-email-Sandeep_Jain@mentor.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1470320194-9602-1-git-send-email-Sandeep_Jain@mentor.com> References: <1470320194-9602-1-git-send-email-Sandeep_Jain@mentor.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vladimir Zapolskiy The change controls module users counter, which prevents to get accidental oops on module unload while it is in use by mtd subsystem: % dd if=/dev/mtd0 of=/dev/null & % rmmod m25p80 Removing MTD device #0 (spi32766.0) with use count 1 Unable to handle kernel paging request at virtual address 7f4fb7f8 pgd = bd094000 [7f4fb7f8] *pgd=4cb66811, *pte=00000000, *ppte=00000000 Internal error: Oops: 80000007 [#1] PREEMPT SMP ARM Signed-off-by: Vladimir Zapolskiy Signed-off-by: Sandeep Jain --- drivers/mtd/devices/m25p80.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c index 9cf7fcd..2eb1530 100644 --- a/drivers/mtd/devices/m25p80.c +++ b/drivers/mtd/devices/m25p80.c @@ -185,6 +185,19 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len, return ret; } +static void m25p80_put(struct mtd_info *mtd) +{ + module_put(THIS_MODULE); +} + +static int m25p80_get(struct mtd_info *mtd) +{ + if (!try_module_get(THIS_MODULE)) + return -ENODEV; + + return 0; +} + /* * board specific setup should have ensured the SPI clock used here * matches what the READ command supports, at least until this driver @@ -212,6 +225,8 @@ static int m25p_probe(struct spi_device *spi) nor->write = m25p80_write; nor->write_reg = m25p80_write_reg; nor->read_reg = m25p80_read_reg; + nor->mtd._put_device = m25p80_put; + nor->mtd._get_device = m25p80_get; nor->dev = &spi->dev; spi_nor_set_flash_node(nor, spi->dev.of_node); -- 1.7.9.5