Re: [RFC v3 4/9] kmsg: add additional buffers support to memory class

2015-10-19 Thread kbuild test robot 
Hi Marcin,

[auto build test ERROR on next-20151016 -- if it's inappropriate base, please 
suggest rules for selecting the more suitable base]

url:
https://github.com/0day-ci/linux/commits/Paul-Osmialowski/Additional-kmsg-devices/20151019-211509
config: x86_64-allnoconfig (attached as .config)
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64 

All errors (new ones prefixed by >>):

   drivers/char/mem.c: In function 'chr_dev_init':
>> drivers/char/mem.c:878:19: error: 'KMSG_MINOR' undeclared (first use in this 
>> function)
 kmsg = init_kmsg(KMSG_MINOR, 0644);
  ^
   drivers/char/mem.c:878:19: note: each undeclared identifier is reported only 
once for each function it appears in

vim +/KMSG_MINOR +878 drivers/char/mem.c

   872  continue;
   873  
   874  device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
   875NULL, devlist[minor].name);
   876  }
   877  
 > 878  kmsg = init_kmsg(KMSG_MINOR, 0644);
   879  if (IS_ERR(kmsg))
   880  return PTR_ERR(kmsg);
   881  

---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all   Intel Corporation


.config.gz
Description: Binary data

[RFC v3 4/9] kmsg: add additional buffers support to memory class

2015-10-19 Thread Paul Osmialowski 
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.