Merge: Revert "nvme_core: scan namespaces asynchronously"

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/699

# Merge Request Required Information

JIRA: https://issues.redhat.com/browse/RHEL-85845

Upstream Status: RHEL-only

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

## Summary of Changes

## Approved Development Ticket(s)
All submissions to CentOS Stream must reference a ticket in [Red Hat Jira](https://issues.redhat.com/).

<details><summary>Click for formatting instructions</summary>
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.

List tickets each on their own line of this description using the format "Resolves: RHEL-76229", "Related: RHEL-76229" or "Reverts: RHEL-76229", as appropriate.
</details>

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>

Merged-by: Julio Faracco <jfaracco@redhat.com>

Author: jcfaracco

drivers/nvme/host/core.c

@@ -4,7 +4,6 @@
  * Copyright (c) 2011-2014, Intel Corporation.
  */
 
-#include <linux/async.h>
 #include <linux/blkdev.h>
 #include <linux/blk-mq.h>
 #include <linux/blk-integrity.h>
@@ -4097,35 +4096,6 @@ static void nvme_scan_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	}
 }
 
-/**
- * struct async_scan_info - keeps track of controller & NSIDs to scan
- * @ctrl:	Controller on which namespaces are being scanned
- * @next_nsid:	Index of next NSID to scan in ns_list
- * @ns_list:	Pointer to list of NSIDs to scan
- *
- * Note: There is a single async_scan_info structure shared by all instances
- * of nvme_scan_ns_async() scanning a given controller, so the atomic
- * operations on next_nsid are critical to ensure each instance scans a unique
- * NSID.
- */
-struct async_scan_info {
-	struct nvme_ctrl *ctrl;
-	atomic_t next_nsid;
-	__le32 *ns_list;
-};
-
-static void nvme_scan_ns_async(void *data, async_cookie_t cookie)
-{
-	struct async_scan_info *scan_info = data;
-	int idx;
-	u32 nsid;
-
-	idx = (u32)atomic_fetch_inc(&scan_info->next_nsid);
-	nsid = le32_to_cpu(scan_info->ns_list[idx]);
-
-	nvme_scan_ns(scan_info->ctrl, nsid);
-}
-
 static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
 					unsigned nsid)
 {
@@ -4152,15 +4122,11 @@ static int nvme_scan_ns_list(struct nvme_ctrl *ctrl)
 	__le32 *ns_list;
 	u32 prev = 0;
 	int ret = 0, i;
-	ASYNC_DOMAIN(domain);
-	struct async_scan_info scan_info;
 
 	ns_list = kzalloc(NVME_IDENTIFY_DATA_SIZE, GFP_KERNEL);
 	if (!ns_list)
 		return -ENOMEM;
 
-	scan_info.ctrl = ctrl;
-	scan_info.ns_list = ns_list;
 	for (;;) {
 		struct nvme_command cmd = {
 			.identify.opcode	= nvme_admin_identify,
@@ -4176,23 +4142,19 @@ static int nvme_scan_ns_list(struct nvme_ctrl *ctrl)
 			goto free;
 		}
 
-		atomic_set(&scan_info.next_nsid, 0);
 		for (i = 0; i < nr_entries; i++) {
 			u32 nsid = le32_to_cpu(ns_list[i]);
 
 			if (!nsid)	/* end of the list? */
 				goto out;
-			async_schedule_domain(nvme_scan_ns_async, &scan_info,
-						&domain);
+			nvme_scan_ns(ctrl, nsid);
 			while (++prev < nsid)
 				nvme_ns_remove_by_nsid(ctrl, prev);
 		}
-		async_synchronize_full_domain(&domain);
 	}
  out:
 	nvme_remove_invalid_namespaces(ctrl, prev);
  free:
-	async_synchronize_full_domain(&domain);
 	kfree(ns_list);
 	return ret;
 }