blk-cgroup: move blkcg_{get,set}_fc_appid out of line

No need to have these helpers inline.  Also remove the stubs and just use
an IS_ENABLED for the get side (the set side already is only built
conditionlly).

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_BLK_DEV_BSG_COMMON) += bsg.o
 obj-$(CONFIG_BLK_DEV_BSGLIB)	+= bsg-lib.o
 obj-$(CONFIG_BLK_CGROUP)	+= blk-cgroup.o
 obj-$(CONFIG_BLK_CGROUP_RWSTAT)	+= blk-cgroup-rwstat.o
+obj-$(CONFIG_BLK_CGROUP_FC_APPID) += blk-cgroup-fc-appid.o
 obj-$(CONFIG_BLK_DEV_THROTTLING)	+= blk-throttle.o
 obj-$(CONFIG_BLK_CGROUP_IOPRIO)	+= blk-ioprio.o
 obj-$(CONFIG_BLK_CGROUP_IOLATENCY)	+= blk-iolatency.o

block/blk-cgroup-fc-appid.c

@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "blk-cgroup.h"
+
+/**
+ * blkcg_set_fc_appid - set the fc_app_id field associted to blkcg
+ * @app_id: application identifier
+ * @cgrp_id: cgroup id
+ * @app_id_len: size of application identifier
+ */
+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;
+}
+EXPORT_SYMBOL_GPL(blkcg_set_fc_appid);
+
+/**
+ * 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
+ */
+char *blkcg_get_fc_appid(struct bio *bio)
+{
+	if (!bio->bi_blkg || bio->bi_blkg->blkcg->fc_app_id[0] == '\0')
+		return NULL;
+	return bio->bi_blkg->blkcg->fc_app_id;
+}
+EXPORT_SYMBOL_GPL(blkcg_get_fc_appid);

drivers/scsi/lpfc/lpfc_scsi.c

@@ -5528,7 +5528,9 @@ static char *lpfc_is_command_vm_io(struct scsi_cmnd *cmd)
 {
 	struct bio *bio = scsi_cmd_to_rq(cmd)->bio;
 
-	return bio ? blkcg_get_fc_appid(bio) : NULL;
+	if (!IS_ENABLED(CONFIG_BLK_CGROUP_FC_APPID) || !bio)
+		return NULL;
+	return blkcg_get_fc_appid(bio);
 }
 
 /**

include/linux/blk-cgroup.h

@@ -218,61 +218,7 @@ static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
 
 #endif	/* CONFIG_BLK_CGROUP */
 
-#ifdef CONFIG_BLK_CGROUP_FC_APPID
+int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len);
-/*
+char *blkcg_get_fc_appid(struct bio *bio);
- * 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 */