Commit d2bcbeab authored by Muneendra Kumar's avatar Muneendra Kumar Committed by Martin K. Petersen
Browse files

scsi: blkcg: Add app identifier support for blkcg 

Add a unique application identifier (i.e fc_app_id member) in blkcg. This
allows identification of traffic belonging to an specific both on the host
and in the fabric infrastructure. As an example, this allows the storage
stack to uniquely identify traffic belong to particular virtual machine.

Link: https://lore.kernel.org/r/20210608043556.274139-3-muneendra.kumar@broadcom.com


Reviewed-by: default avatarHimanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarMuneendra Kumar <muneendra.kumar@broadcom.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 6b658c48

block/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -144,6 +144,15 @@ config BLK_CGROUP_IOLATENCY 


	Note, this is an experimental interface and could be changed someday.



config BLK_CGROUP_FC_APPID

	bool "Enable support to track FC I/O Traffic across cgroup applications"

	depends on BLK_CGROUP=y

	help

	  Enabling this option enables the support to track FC I/O traffic across

	  cgroup applications. It enables the Fabric and the storage targets to

	  identify, monitor, and handle FC traffic based on VM tags by inserting

	  application specific identification into the FC frame.



config BLK_CGROUP_IOCOST

	bool "Enable support for cost model based cgroup IO controller"

	depends on BLK_CGROUP=y

drivers/scsi/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -235,6 +235,19 @@ config SCSI_FC_ATTRS 
	  each attached FiberChannel device to sysfs, say Y.

	  Otherwise, say N.



config FC_APPID

	bool "Enable support to track FC I/O Traffic"

	depends on BLOCK && BLK_CGROUP

	depends on SCSI

	select BLK_CGROUP_FC_APPID

	default y

	help

	  If you say Y here, it enables the support to track

	  FC I/O traffic over fabric. It enables the Fabric and the

	  storage targets to identify, monitor, and handle FC traffic

	  based on VM tags by inserting application specific

	  identification into the FC frame.



config SCSI_ISCSI_ATTRS

	tristate "iSCSI Transport Attributes"

	depends on SCSI && NET

include/linux/blk-cgroup.h

+63 −0
Original line number Diff line number Diff line
@@ -30,6 +30,8 @@ 


/* Max limits for throttle policy */

#define THROTL_IOPS_MAX		UINT_MAX

#define FC_APPID_LEN              129





#ifdef CONFIG_BLK_CGROUP
@@ -55,6 +57,9 @@ struct blkcg { 
	struct blkcg_policy_data	*cpd[BLKCG_MAX_POLS];



	struct list_head		all_blkcgs_node;

#ifdef CONFIG_BLK_CGROUP_FC_APPID

	char                            fc_app_id[FC_APPID_LEN];

#endif

#ifdef CONFIG_CGROUP_WRITEBACK

	struct list_head		cgwb_list;

#endif
@@ -660,4 +665,62 @@ static inline void blk_cgroup_bio_start(struct bio *bio) { } 


#endif	/* CONFIG_BLOCK */

#endif	/* CONFIG_BLK_CGROUP */



#ifdef CONFIG_BLK_CGROUP_FC_APPID

/*

 * Sets the fc_app_id field associted to blkcg

 * @app_id: application identifier

 * @cgrp_id: cgroup id

 * @app_id_len: size of application identifier

 */

static inline int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len)

{

	struct cgroup *cgrp;

	struct cgroup_subsys_state *css;

	struct blkcg *blkcg;

	int ret  = 0;



	if (app_id_len > FC_APPID_LEN)

		return -EINVAL;



	cgrp = cgroup_get_from_id(cgrp_id);

	if (!cgrp)

		return -ENOENT;

	css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);

	if (!css) {

		ret = -ENOENT;

		goto out_cgrp_put;

	}

	blkcg = css_to_blkcg(css);

	/*

	 * There is a slight race condition on setting the appid.

	 * Worst case an I/O may not find the right id.

	 * This is no different from the I/O we let pass while obtaining

	 * the vmid from the fabric.

	 * Adding the overhead of a lock is not necessary.

	 */

	strlcpy(blkcg->fc_app_id, app_id, app_id_len);

	css_put(css);

out_cgrp_put:

	cgroup_put(cgrp);

	return ret;

}



/**

 * blkcg_get_fc_appid - get the fc app identifier associated with a bio

 * @bio: target bio

 *

 * On success return the fc_app_id, on failure return NULL

 */

static inline char *blkcg_get_fc_appid(struct bio *bio)

{

	if (bio && bio->bi_blkg &&

		(bio->bi_blkg->blkcg->fc_app_id[0] != '\0'))

		return bio->bi_blkg->blkcg->fc_app_id;

	return NULL;

}

#else

static inline int blkcg_set_fc_appid(char *buf, u64 id, size_t len) { return -EINVAL; }

static inline char *blkcg_get_fc_appid(struct bio *bio) { return NULL; }

#endif /*CONFIG_BLK_CGROUP_FC_APPID*/

#endif	/* _BLK_CGROUP_H */