Hi Rui,
Refer to inline:).
On 07/29/2013 10:31 AM, Rui Xiang wrote:
> Add a struct syslog_namespace which contains the necessary
> members for hanlding syslog and realize get_syslog_ns and
> put_syslog_ns API.
>
> Signed-off-by: Rui Xiang <rui.xiang@xxxxxxxxxx>
> ---
> include/linux/syslog.h | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++
> kernel/printk.c | 7 ------
> 2 files changed, 68 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/syslog.h b/include/linux/syslog.h
> index 98a3153..425fafe 100644
> --- a/include/linux/syslog.h
> +++ b/include/linux/syslog.h
> @@ -21,6 +21,9 @@
> #ifndef _LINUX_SYSLOG_H
> #define _LINUX_SYSLOG_H
>
> +#include <linux/slab.h>
> +#include <linux/kref.h>
> +
> /* Close the log. Currently a NOP. */
> #define SYSLOG_ACTION_CLOSE 0
> /* Open the log. Currently a NOP. */
> @@ -47,6 +50,71 @@
> #define SYSLOG_FROM_READER 0
> #define SYSLOG_FROM_PROC 1
>
> +enum log_flags {
> + LOG_NOCONS = 1, /* already flushed, do not print to console */
> + LOG_NEWLINE = 2, /* text ended with a newline */
> + LOG_PREFIX = 4, /* text started with a prefix */
> + LOG_CONT = 8, /* text is a fragment of a continuation line */
> +};
> +
> +struct syslog_namespace {
> + struct kref kref; /* syslog_ns reference count & control */
> +
> + raw_spinlock_t logbuf_lock; /* access conflict locker */
> + /* cpu currently holding logbuf_lock of ns */
> + unsigned int logbuf_cpu;
> +
> + /* index and sequence number of the first record stored in the buffer */
> + u64 log_first_seq;
> + u32 log_first_idx;
> +
> + /* index and sequence number of the next record stored in the buffer */
> + u64 log_next_seq;
> + u32 log_next_idx;
> +
> + /* the next printk record to read after the last 'clear' command */
> + u64 clear_seq;
> + u32 clear_idx;
> +
> + char *log_buf;
> + u32 log_buf_len;
> +
> + /* the next printk record to write to the console */
> + u64 console_seq;
> + u32 console_idx;
> +
> + /* the next printk record to read by syslog(READ) or /proc/kmsg */
> + u64 syslog_seq;
> + u32 syslog_idx;
> + enum log_flags syslog_prev;
> + size_t syslog_partial;
> +
> + int dmesg_restrict;
> +};
> +
> +static inline struct syslog_namespace *get_syslog_ns(
> + struct syslog_namespace *ns)
> +{
> + if (ns)
> + kref_get(&ns->kref);
> + return ns;
> +}
> +
> +static inline void free_syslog_ns(struct kref *kref)
> +{
> + struct syslog_namespace *ns;
> + ns = container_of(kref, struct syslog_namespace, kref);
> +
> + kfree(ns->log_buf);
> + kfree(ns);
> +}
This interface seems a bit ugly, why not use the format like put_syslog_ns()?
static inline void free_syslog_ns(struct syslog_namespace *ns)
> +
> +static inline void put_syslog_ns(struct syslog_namespace *ns)
> +{
> + if (ns)
> + kref_put(&ns->kref, free_syslog_ns);
> +}
> +
> int do_syslog(int type, char __user *buf, int count, bool from_file);
>
> #endif /* _LINUX_SYSLOG_H */
> diff --git a/kernel/printk.c b/kernel/printk.c
> index d37d45c..7e544bf 100644
> --- a/kernel/printk.c
> +++ b/kernel/printk.c
> @@ -193,13 +193,6 @@ static int console_may_schedule;
> * separated by ',', and find the message after the ';' character.
> */
>
> -enum log_flags {
> - LOG_NOCONS = 1, /* already flushed, do not print to console */
> - LOG_NEWLINE = 2, /* text ended with a newline */
> - LOG_PREFIX = 4, /* text started with a prefix */
> - LOG_CONT = 8, /* text is a fragment of a continuation line */
> -};
> -
> struct log {
> u64 ts_nsec; /* timestamp in nanoseconds */
> u16 len; /* length of entire record */
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