Merge: nvme: fix reconnection fail due to reserved tag allocation

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4443

# Merge Request Required Information

JIRA: https://issues.redhat.com/browse/RHEL-36896

CVE: CVE-2024-27435

## Summary of Changes


## Approved Development Ticket
All submissions to CentOS Stream must reference an approved ticket in [Red Hat Jira](https://issues.redhat.com/). Please follow the CentOS Stream [contribution documentation](https://docs.centos.org/en-US/stream-contrib/quickstart/) for how to file this ticket and have it approved.

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>

Approved-by: John Meneghini <jmeneghi@redhat.com>
Approved-by: Chris Leech <cleech@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>
Approved-by: Tomas Henzl <thenzl@redhat.com>

Merged-by: Lucas Zampieri <lzampier@redhat.com>

Author: zampierilucas

drivers/nvme/host/core.c

@@ -4384,7 +4384,8 @@ int nvme_alloc_admin_tag_set(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set,
 	set->ops = ops;
 	set->queue_depth = NVME_AQ_MQ_TAG_DEPTH;
 	if (ctrl->ops->flags & NVME_F_FABRICS)
-		set->reserved_tags = NVMF_RESERVED_TAGS;
+		/* Reserved for fabric connect and keep alive */
+		set->reserved_tags = 2;
 	set->numa_node = ctrl->numa_node;
 	set->flags = BLK_MQ_F_NO_SCHED;
 	if (ctrl->ops->flags & NVME_F_BLOCKING)
@@ -4453,7 +4454,8 @@ int nvme_alloc_io_tag_set(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set,
 	if (ctrl->quirks & NVME_QUIRK_SHARED_TAGS)
 		set->reserved_tags = NVME_AQ_DEPTH;
 	else if (ctrl->ops->flags & NVME_F_FABRICS)
-		set->reserved_tags = NVMF_RESERVED_TAGS;
+		/* Reserved for fabric connect */
+		set->reserved_tags = 1;
 	set->numa_node = ctrl->numa_node;
 	set->flags = BLK_MQ_F_SHOULD_MERGE;
 	if (ctrl->ops->flags & NVME_F_BLOCKING)

drivers/nvme/host/fabrics.h

@@ -18,13 +18,6 @@
 /* default is -1: the fail fast mechanism is disabled  */
 #define NVMF_DEF_FAIL_FAST_TMO		-1
 
-/*
- * Reserved one command for internal usage.  This command is used for sending
- * the connect command, as well as for the keep alive command on the admin
- * queue once live.
- */
-#define NVMF_RESERVED_TAGS	1
-
 /*
  * Define a host as seen by the target.  We allocate one at boot, but also
  * allow the override it when creating controllers.  This is both to provide