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: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Muneendra Kumar <muneendra.kumar@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/block/Kconfig b/block/Kconfig
index a2297edfdde88d1a6390cf22211fe4bbb863105a..03886d1053018e9b0b7bec5c11069ec3f22b5fa3 100644 (file)
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -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

diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 23e015af0e930fd427a7e96591c8bf3cfd97ea48..cd5fbd9d46ba3e9f3df625fffcd45058db219136 100644 (file)
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -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

diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index b9f3c246c3c908b1145e41fb95cc050922c85f2f..37048438872c86f9c52ddc1b31ea30fd89e0b155 100644 (file)
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -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 */