Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031768AbbKECg6 (ORCPT ); Wed, 4 Nov 2015 21:36:58 -0500 Received: from mail9.hitachi.co.jp ([133.145.228.44]:42406 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031712AbbKECgy (ORCPT ); Wed, 4 Nov 2015 21:36:54 -0500 Subject: [PATCH 3/5] pstore: support multiple pmsg instances From: Hiraku Toyooka To: linux-kernel@vger.kernel.org Cc: Tony Luck , Kees Cook , Seiji Aguchi , Mark Salyzyn , Anton Vorontsov , Colin Cross Date: Thu, 05 Nov 2015 11:36:51 +0900 Message-ID: <20151105023651.3367.63082.stgit@arietta> In-Reply-To: <20151105023644.3367.94795.stgit@arietta> References: <20151105023644.3367.94795.stgit@arietta> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3099 Lines: 90 This patch 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 a 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 Cc: Anton Vorontsov Cc: Colin Cross Cc: Kees Cook Cc: Mark Salyzyn Cc: Seiji Aguchi Cc: Tony Luck Cc: linux-kernel@vger.kernel.org --- fs/pstore/pmsg.c | 20 ++++++++++++++++++-- include/linux/pstore.h | 1 + 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/fs/pstore/pmsg.c b/fs/pstore/pmsg.c index feb5dd2..3467d63 100644 --- a/fs/pstore/pmsg.c +++ b/fs/pstore/pmsg.c @@ -50,8 +50,8 @@ static ssize_t write_pmsg(struct file *file, const char __user *buf, vfree(buffer); return -EFAULT; } - psinfo->write_buf(PSTORE_TYPE_PMSG, 0, &id, 0, buffer, 0, c, - psinfo); + psinfo->write_buf(PSTORE_TYPE_PMSG, 0, &id, + iminor(file->f_inode), buffer, 0, c, psinfo); i += c; } @@ -83,6 +83,7 @@ static char *pmsg_devnode(struct device *dev, umode_t *mode) void pstore_register_pmsg(void) { struct device *pmsg_device; + int i = 0; pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops); if (pmsg_major < 0) { @@ -103,9 +104,24 @@ void pstore_register_pmsg(void) pr_err("failed to create device\n"); goto err_device; } + + /* allocate additional /dev/pmsg[ID] */ + for (i = 1; 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 8e7a25b..7cffc9d 100644 --- a/include/linux/pstore.h +++ b/include/linux/pstore.h @@ -54,6 +54,7 @@ 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, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/