From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932353AbdAaB70 (ORCPT ); Mon, 30 Jan 2017 20:59:26 -0500 Received: from mail9.hitachi.co.jp ([133.145.228.44]:54012 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932263AbdAaB7W (ORCPT ); Mon, 30 Jan 2017 20:59:22 -0500 From: Nobuhiro Iwamatsu To: Anton Vorontsov , Colin Cross , Kees Cook , Tony Luck Cc: linux-kernel@vger.kernel.org, Hiraku Toyooka , Nobuhiro Iwamatsu , Mark Salyzyn , Seiji Aguchi Subject: [PATCH v4 2nd 2/4] pstore: support multiple pmsg instances Date: Tue, 31 Jan 2017 10:58:33 +0900 Message-Id: <1485827915-9620-3-git-send-email-nobuhiro.iwamatsu.kw@hitachi.com> X-Mailer: git-send-email 2.8.1.windows.1 In-Reply-To: <1485827915-9620-1-git-send-email-nobuhiro.iwamatsu.kw@hitachi.com> References: <1485827915-9620-1-git-send-email-nobuhiro.iwamatsu.kw@hitachi.com> X-TM-AS-GCONF: 00 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hiraku Toyooka This enables pmsg to deal with multiple instances. One possible use is content priority control on limited persistent store space. By using different buffers, we can prevent important messages from being overwritten by less important messages. When pstore backend module specifies the number of instances (num_pmsg) in pstore_info, multiple /dev/pmsg[ID] appear. (ID is an integer starting at 0. It corresponds to minor number of the each char device.) Writes to each /dev/pmsg[ID] are isolated each other. After reboot, the contents are available in /sys/fs/pstore/pmsg-[backend]-[ID]. Signed-off-by: Hiraku Toyooka Signed-off-by: Nobuhiro Iwamatsu Cc: Anton Vorontsov Cc: Colin Cross Cc: Kees Cook Cc: Mark Salyzyn Cc: Seiji Aguchi Cc: Tony Luck V4: Rebase. V3: rebase. merged device_create(). --- fs/pstore/pmsg.c | 23 ++++++++++++++++------- include/linux/pstore.h | 1 + 2 files changed, 17 insertions(+), 7 deletions(-) diff --git a/fs/pstore/pmsg.c b/fs/pstore/pmsg.c index 78f6176c020f..5da5cba4b387 100644 --- a/fs/pstore/pmsg.c +++ b/fs/pstore/pmsg.c @@ -34,7 +34,8 @@ static ssize_t write_pmsg(struct file *file, const char __user *buf, return -EFAULT; mutex_lock(&pmsg_lock); - ret = psinfo->write_buf_user(PSTORE_TYPE_PMSG, 0, &id, 0, buf, 0, count, + ret = psinfo->write_buf_user(PSTORE_TYPE_PMSG, 0, &id, + iminor(file->f_inode), buf, 0, count, psinfo); mutex_unlock(&pmsg_lock); return ret ? ret : count; @@ -61,7 +62,7 @@ static char *pmsg_devnode(struct device *dev, umode_t *mode) void pstore_register_pmsg(void) { - struct device *pmsg_device; + int i; pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops); if (pmsg_major < 0) { @@ -76,15 +77,23 @@ void pstore_register_pmsg(void) } pmsg_class->devnode = pmsg_devnode; - pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0), - NULL, "%s%d", PMSG_NAME, 0); - if (IS_ERR(pmsg_device)) { - pr_err("failed to create device\n"); - goto err_device; + /* allocate additional /dev/pmsg[ID] */ + for (i = 0; i < psinfo->num_pmsg; i++) { + struct device *pmsg_device; + + pmsg_device = device_create(pmsg_class, NULL, + MKDEV(pmsg_major, i), NULL, "%s%d", + PMSG_NAME, i); + if (IS_ERR(pmsg_device)) { + pr_err("failed to create device\n"); + goto err_device; + } } return; err_device: + for (i--; i >= 0; i--) + device_destroy(pmsg_class, MKDEV(pmsg_major, i)); class_destroy(pmsg_class); err_class: unregister_chrdev(pmsg_major, PMSG_NAME); diff --git a/include/linux/pstore.h b/include/linux/pstore.h index 0da29cae009b..7a5db4833b8a 100644 --- a/include/linux/pstore.h +++ b/include/linux/pstore.h @@ -55,6 +55,7 @@ struct pstore_info { size_t bufsize; struct mutex read_mutex; /* serialize open/read/close */ int flags; + unsigned int num_pmsg; int (*open)(struct pstore_info *psi); int (*close)(struct pstore_info *psi); ssize_t (*read)(u64 *id, enum pstore_type_id *type, -- 2.11.0