From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932072AbbJSM6x (ORCPT ); Mon, 19 Oct 2015 08:58:53 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:59984 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753387AbbJSM6r (ORCPT ); Mon, 19 Oct 2015 08:58:47 -0400 X-AuditID: cbfec7f4-f79c56d0000012ee-98-5624e9044ee5 From: Paul Osmialowski To: Jonathan Corbet , Arnd Bergmann , Andrew Morton , Petr Mladek , Greg Kroah-Hartman , Daniel Mack , Kay Sievers , Joe Perches , Tejun Heo , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-api@vger.kernel.org Cc: Marcin Niesluchowski , Karol Lewandowski , Paul Osmialowski , Bartlomiej Zolnierkiewicz , Shuah Khan Subject: [RFC v3 4/9] kmsg: add additional buffers support to memory class Date: Mon, 19 Oct 2015 14:58:18 +0200 Message-id: <1445259503-18158-5-git-send-email-p.osmialowsk@samsung.com> X-Mailer: git-send-email 1.9.1 In-reply-to: <1445259503-18158-1-git-send-email-p.osmialowsk@samsung.com> References: <1445259503-18158-1-git-send-email-p.osmialowsk@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrGLMWRmVeSWpSXmKPExsVy+t/xa7osL1XCDLrf61rMWb+GzeLvpGPs FhtnrGe1eHKgndGi6e8rFovmxevZLGbff8xi0fhpLrPF5Q3n2Cw2f+9gs1jYtoTF4vKuOWwW h87+YLGY8OYAs8XC/5uZLKZ++cBi8Wv5UUYHQY/fvyYxemxa1cnmcWLGbxaP/XPXsHss7pvM 6rGl/y67x5dV15g9+rasYvQ4s+AIu8fnTXIeH9d7emzfvZwlgCeKyyYlNSezLLVI3y6BK+Nm 20u2gmeaFed+HWRpYLyt2MXIySEhYCIxf8YERghbTOLCvfVsILaQwFJGiZbd0l2MXEB2I5PE kcMfmUASbAKGEjf/H2YESYgIzGWWaP61gBXEYRb4xCjxY+1ydpAqYQEviYf7+4E62DlYBFQl DjKDRHkFPCRufF7BBLFMTuLkscmsIDangKfEvE8TgTo5gJZ5SPyf6TiBkXcBI8MqRtHU0uSC 4qT0XEO94sTc4tK8dL3k/NxNjJDQ/7KDcfExq0OMAhyMSjy8N+pVwoRYE8uKK3MPMUpwMCuJ 8F6+ARTiTUmsrEotyo8vKs1JLT7EKM3BoiTOO3fX+xAhgfTEktTs1NSC1CKYLBMHp1QDI+uW dyZn58TkB2lW7z7wnn+PXdCDF58DPtg/ffX4Qc/XGxKHH6Q2T7hbevHFqcAYk70bDx4//JvF 5urnHVEdKhfnHZrlo5159dMa9dAblxd/jf76X/psA+PrBQetviisUrvJMbHvFFORYXDZzYBb 3v7pBQKFF+VPbtx3VYhFjeuwwHW3V+kp0j1KLMUZiYZazEXFiQC/tdgheQIAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marcin Niesluchowski Memory class does not support additional kmsg buffers. Add additional kmsg buffers support to: * devnode() callback of "mem" class * file operations of major "mem" character device Signed-off-by: Marcin Niesluchowski Signed-off-by: Paul Osmialowski --- drivers/char/mem.c | 27 ++++++++++++++++++++------- include/linux/printk.h | 32 ++++++++++++++++++++++++++++++++ kernel/printk/kmsg.c | 42 ++++++++++++++++++++++++++++++++++++++++++ kernel/printk/printk.c | 1 + kernel/printk/printk.h | 1 + 5 files changed, 96 insertions(+), 7 deletions(-) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 6b1721f..7d46234 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -799,9 +799,6 @@ static const struct memdev { [7] = { "full", 0666, &full_fops, 0 }, [8] = { "random", 0666, &random_fops, 0 }, [9] = { "urandom", 0666, &urandom_fops, 0 }, -#ifdef CONFIG_PRINTK - [11] = { "kmsg", 0644, &kmsg_fops, 0 }, -#endif }; static int memory_open(struct inode *inode, struct file *filp) @@ -811,7 +808,7 @@ static int memory_open(struct inode *inode, struct file *filp) minor = iminor(inode); if (minor >= ARRAY_SIZE(devlist)) - return -ENXIO; + return kmsg_memory_open(inode, filp); dev = &devlist[minor]; if (!dev->fops) @@ -833,16 +830,28 @@ static const struct file_operations memory_fops = { static char *mem_devnode(struct device *dev, umode_t *mode) { - if (mode && devlist[MINOR(dev->devt)].mode) - *mode = devlist[MINOR(dev->devt)].mode; + int minor = MINOR(dev->devt); + + if (!mode) + goto out; + + if (minor >= ARRAY_SIZE(devlist)) { + kmsg_mode(minor, mode); + goto out; + } + + if (devlist[minor].mode) + *mode = devlist[minor].mode; +out: return NULL; } -static struct class *mem_class; +struct class *mem_class; static int __init chr_dev_init(void) { int minor; + struct device *kmsg; if (register_chrdev(MEM_MAJOR, "mem", &memory_fops)) printk("unable to get major %d for memory devs\n", MEM_MAJOR); @@ -866,6 +875,10 @@ static int __init chr_dev_init(void) NULL, devlist[minor].name); } + kmsg = init_kmsg(KMSG_MINOR, 0644); + if (IS_ERR(kmsg)) + return PTR_ERR(kmsg); + return tty_init(); } diff --git a/include/linux/printk.h b/include/linux/printk.h index 9729565..67840e0 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -417,8 +417,40 @@ do { \ no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) #endif +struct file; +struct inode; + +#ifdef CONFIG_PRINTK + +extern struct class *mem_class; + +#define KMSG_MINOR 11 + extern const struct file_operations kmsg_fops; +extern struct device *init_kmsg(int minor, umode_t mode); +extern int kmsg_memory_open(struct inode *inode, struct file *filp); +extern int kmsg_mode(int minor, umode_t *mode); + +#else + +static inline struct device *init_kmsg(int minor, umode_t mode) +{ + return NULL; +} + +static inline int kmsg_memory_open(struct inode *inode, struct file *filp) +{ + return -ENXIO; +} + +static inline int kmsg_mode(int minor, umode_t *mode) +{ + return -ENXIO; +} + +#endif + enum { DUMP_PREFIX_NONE, DUMP_PREFIX_ADDRESS, diff --git a/kernel/printk/kmsg.c b/kernel/printk/kmsg.c index 23d4160..7fcd628 100644 --- a/kernel/printk/kmsg.c +++ b/kernel/printk/kmsg.c @@ -15,6 +15,9 @@ #include #include #include +#include +#include +#include #include @@ -385,6 +388,45 @@ const struct file_operations kmsg_fops = { .release = devkmsg_release, }; +/* Should be used for device registration */ +struct device *init_kmsg(int minor, umode_t mode) +{ + log_buf.minor = minor; + log_buf.mode = mode; + return device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), + NULL, "kmsg"); +} + +int kmsg_memory_open(struct inode *inode, struct file *filp) +{ + filp->f_op = &kmsg_fops; + + return kmsg_fops.open(inode, filp); +} + +int kmsg_mode(int minor, umode_t *mode) +{ + int ret = -ENXIO; + struct log_buffer *log_b; + + if (minor == log_buf.minor) { + *mode = log_buf.mode; + return 0; + } + + rcu_read_lock(); + list_for_each_entry_rcu(log_b, &log_buf.list, list) { + if (log_b->minor == minor) { + *mode = log_b->mode; + ret = 0; + break; + } + } + rcu_read_unlock(); + + return ret; +} + static DEFINE_SPINLOCK(dump_list_lock); static LIST_HEAD(dump_list); diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index e9ac4ba..beabebb 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -179,6 +179,7 @@ struct log_buffer log_buf = { .next_idx = 0, .clear_seq = 0, .clear_idx = 0, + .mode = 0, .minor = 0, }; diff --git a/kernel/printk/printk.h b/kernel/printk/printk.h index 38c9278..0755100 100644 --- a/kernel/printk/printk.h +++ b/kernel/printk/printk.h @@ -118,6 +118,7 @@ struct log_buffer { u64 clear_seq; u32 clear_idx; + int mode; /* mode of device */ int minor; /* minor representing buffer device */ #endif }; -- 1.9.1