Re: [RFC 3/8] kmsg: introduce additional kmsg devices support
From: Petr Mladek <pmladek@suse.com>
Date: 2015-07-08 11:11:10
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On Fri 2015-07-03 12:49:50, Marcin Niesluchowski wrote:
kmsg device provides operations on cyclic logging buffer used mainly by kernel but also in userspace by privileged processes. Additional kmsg devices keep the same log format but may be added dynamically with custom size. Signed-off-by: Marcin Niesluchowski <redacted>
quoted hunk ↗ jump to hunk
--- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c@@ -234,29 +234,37 @@ struct printk_log { u8 level:3; /* syslog level */ };
Just in case, this is accepted. If you already touch the API, I would suggest to rename struct printk_log to printk_msg. The current name is pretty misleading.
+struct log_buffer {
+#ifdef CONFIG_PRINTK
+ struct list_head list; /* kmsg as head of the list */
+ char *buf; /* cyclic log buffer */
+ u32 len; /* buffer length */
+ wait_queue_head_t wait; /* wait queue for kmsg buffer */
+#endif
/*
- * The logbuf_lock protects kmsg buffer, indices, counters. This can be taken
- * within the scheduler's rq lock. It must be released before calling
- * console_unlock() or anything else that might wake up a process.
+ * The lock protects kmsg buffer, indices, counters. This can be taken within
+ * the scheduler's rq lock. It must be released before calling console_unlock()
+ * or anything else that might wake up a process.
*/
-static DEFINE_RAW_SPINLOCK(logbuf_lock);
+ raw_spinlock_t lock;
+ u64 first_seq; /* sequence number of the first record stored */
+ u32 first_idx; /* index of the first record stored */
+/* sequence number of the next record to store */
+ u64 next_seq;
+#ifdef CONFIG_PRINTK
+ u32 next_idx; /* index of the next record to store */
+ int mode; /* mode of device (kmsg_sys only) */
+ int minor; /* minor representing buffer device */
+#endif
+};quoted hunk ↗ jump to hunk
@@ -1069,10 +1253,10 @@ const struct file_operations kmsg_fops = { */ void log_buf_kexec_setup(void) { - VMCOREINFO_SYMBOL(log_buf); - VMCOREINFO_SYMBOL(log_buf_len); - VMCOREINFO_SYMBOL(log_first_idx); - VMCOREINFO_SYMBOL(log_next_idx); + VMCOREINFO_SYMBOL(log_buf.buf); + VMCOREINFO_SYMBOL(log_buf.len); + VMCOREINFO_SYMBOL(log_buf.first_idx); + VMCOREINFO_SYMBOL(log_buf.next_idx);
Have you tried to use this in crash or some other utility, please? I guess that it will need to be exported a similar way like struct printk_log, something like: VMCOREINFO_SYMBOL(log_buf); VMCOREINFO_STRUCT_SIZE(log_buffer); VMCOREINFO_OFFSET(log_buffer, buf); VMCOREINFO_OFFSET(log_buffer, len); VMCOREINFO_OFFSET(log_buffer, first_idx); VMCOREINFO_OFFSET(log_buffer, next_idx); Best Regards, Petr