[lttng-dev] [Patch][Lttng Modules] Statedump event for block devices

[Julien Desfossez]

Tested-by: Julien Desfossez <jdesfossez at efficios.com>

On 14-04-15 12:06 PM, Houssem Daoud wrote:
> Signed-off-by: Houssem Daoud <houssemmh at gmail.com>
> ---
>  .../events/lttng-module/lttng-statedump.h          | 15 ++++++
>  lttng-statedump-impl.c                             | 60 ++++++++++++++++++++++
>  2 files changed, 75 insertions(+)
> 
> diff --git a/instrumentation/events/lttng-module/lttng-statedump.h b/instrumentation/events/lttng-module/lttng-statedump.h
> index e4c86d6..07afdd0 100644
> --- a/instrumentation/events/lttng-module/lttng-statedump.h
> +++ b/instrumentation/events/lttng-module/lttng-statedump.h
> @@ -141,6 +141,21 @@ TRACE_EVENT(lttng_statedump_network_interface,
>  	TP_printk("")
>  )
>  
> +TRACE_EVENT(lttng_statedump_block_device,
> +	TP_PROTO(struct lttng_session *session,
> +		int dev, const char *diskname),
> +	TP_ARGS(session, dev, diskname),
> +	TP_STRUCT__entry(
> +		__field(int, dev)
> +		__string(diskname, diskname)
> +	),
> +	TP_fast_assign(
> +		tp_assign(dev, dev)
> +		tp_strcpy(diskname, diskname)
> +	),
> +	TP_printk("")
> +)
> +
>  /* Called with desc->lock held */
>  TRACE_EVENT(lttng_statedump_interrupt,
>  	TP_PROTO(struct lttng_session *session,
> diff --git a/lttng-statedump-impl.c b/lttng-statedump-impl.c
> index 40eab8e..fd0063e 100644
> --- a/lttng-statedump-impl.c
> +++ b/lttng-statedump-impl.c
> @@ -26,6 +26,10 @@
>   *	                                Various updates
>   */
>  
> +#include <linux/ctype.h>
> +#include <linux/string.h>
> +#include <linux/genhd.h>
> +#include <linux/device.h>
>  #include <linux/init.h>
>  #include <linux/module.h>
>  #include <linux/netlink.h>
> @@ -54,6 +58,7 @@
>  #include "wrapper/nsproxy.h"
>  #include "wrapper/irq.h"
>  #include "wrapper/tracepoint.h"
> +#include "wrapper/kallsyms.h"
>  
>  #ifdef CONFIG_LTTNG_HAS_LIST_IRQ
>  #include <linux/irq.h>
> @@ -108,7 +113,61 @@ enum lttng_process_status {
>  	LTTNG_DEAD = 7,
>  };
>  
> +
> +char *disk_name(struct gendisk *hd, int partno, char *buf)
> +{
> +	if (!partno)
> +		snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
> +	else if (isdigit(hd->disk_name[strlen(hd->disk_name) - 1]))
> +		snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
> +	else
> +		snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
> +
> +	return buf;
> +}
> +
> +static
> +int lttng_enumerate_block_devices(struct lttng_session *session) {
> +	struct class *ptr_block_class;
> +	struct device_type *ptr_disk_type;
> +	struct class_dev_iter iter;
> +	struct device *dev;
> +	struct gendisk *disk;
> +	struct disk_part_iter piter;
> +	struct hd_struct *part;
> +	char name_buf[BDEVNAME_SIZE];
> +	int device_devt;
> +
> +	ptr_block_class = (struct class *) kallsyms_lookup_dataptr("block_class");
> +	if (!ptr_block_class){
> +		printk( KERN_WARNING "Lttng: block_class symbol lookup failed.\n");
> +		return 0;
> +	}
> +
> +	ptr_disk_type = (struct device_type*) kallsyms_lookup_dataptr("disk_type");
> +	if (!ptr_disk_type){
> +		printk( KERN_WARNING "Lttng: disk_type symbol lookup failed.\n");
> +		return 0;
> +	}
> +
> +	class_dev_iter_init(&iter, ptr_block_class, NULL, ptr_disk_type);
> +	while ((dev = class_dev_iter_next(&iter))) {
> +		disk = dev_to_disk(dev);
> +		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
> +		while ((part = disk_part_iter_next(&piter))) {
> +			disk_name(disk, part->partno, name_buf);
> +			device_devt = (int) part_devt(part);
> +			trace_lttng_statedump_block_device(session, device_devt, name_buf);
> +		}
> +		disk_part_iter_exit(&piter);
> +	}
> +	class_dev_iter_exit(&iter);
> +
> +	return 0;
> +}
> +
>  #ifdef CONFIG_INET
> +
>  static
>  void lttng_enumerate_device(struct lttng_session *session,
>  		struct net_device *dev)
> @@ -390,6 +449,7 @@ int do_lttng_statedump(struct lttng_session *session)
>  	/* FIXME lttng_enumerate_vm_maps(session); */
>  	lttng_list_interrupts(session);
>  	lttng_enumerate_network_ip_interface(session);
> +	lttng_enumerate_block_devices(session);
>  
>  	/* TODO lttng_dump_idt_table(session); */
>  	/* TODO lttng_dump_softirq_vec(session); */
>