RE: [PATCH 2/2] multipathd: set rport port_state to marginal for NVMe devices

[Muneendra Kumar M <muneendra.kumar@broadcom.com>]

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Hi Benjamin,
Thanks for the changes.
But below is the reason why we didn't add support to set the rport
port_state to marginal for NVMe devices

In the case of SCSI  once rport-state is set to Marginal ,
If any pending I/O's on the marginal path hit's the scsi-timeout (after
abort success) the scsi-layer checks the rport-state  and If the
rport-state is set to Marginal it will not do any retries on the Marginal
path instead the I/O
Will be retried on the other Active paths.


This particular functionality(checking the rport-state and acting
accordingly) we didn't add( as far I know) in the case of NVME and we need
to check how we can handle this in the case of NVME .
That's the reason we didn't set the port state to Marginal in the case of
NVMe.


In a brief SCSI layer handles the case when the rport-state is set to
Marginal whereas in NVMe it doesn't(AFIK).

Atleast with the below changes we make sure that once we get the FPIN-LI
notification we will set the affected path , as well as the rport-state to
Marginal irrespective of SCSI and NVMe.

I am just thinking that until we have some changes in the NVME driver to
handle (the rport-state to marginal) this changes doesn't show any impact
in the case of NVMe
 other then keeping it  on par with SCSI implementation.

Please let me know your opinion on the same.


Regards,
Muneendra.



-----Original Message-----
From: Benjamin Marzinski <bmarzins@redhat.com>
Sent: Friday, December 20, 2024 7:33 AM
To: Christophe Varoqui <christophe.varoqui@opensvc.com>
Cc: device-mapper development <dm-devel@lists.linux.dev>; Martin Wilck
<Martin.Wilck@suse.com>; Muneendra Kumar <muneendra.kumar@broadcom.com>
Subject: [PATCH 2/2] multipathd: set rport port_state to marginal for NVMe
devices

When a scsi path device is set to marginal, it updates the rport state.
Do this for NVMe devices as well.

Fixes: 1cada778 ("multipathd: Added support to handle FPIN-Li events for
FC-NVMe")
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 multipathd/fpin_handlers.c | 74 ++++++++++++++++++++++++++++++++++----
 1 file changed, 68 insertions(+), 6 deletions(-)

diff --git a/multipathd/fpin_handlers.c b/multipathd/fpin_handlers.c index
6b56f9b7..8b436067 100644
--- a/multipathd/fpin_handlers.c
+++ b/multipathd/fpin_handlers.c
@@ -15,6 +15,7 @@
 #include "debug.h"
 #include "util.h"
 #include "sysfs.h"
+#include "discovery.h"

 #include "fpin.h"
 #include "devmapper.h"
@@ -253,7 +254,7 @@ static int  extract_nvme_addresses_chk_path_pwwn(const
char *address,
  * with the els wwpn ,attached_wwpn and sets the path state to
  * Marginal
  */
-static void fpin_check_set_nvme_path_marginal(uint16_t host_num, struct
path *pp,
+static bool fpin_check_set_nvme_path_marginal(uint16_t host_num, struct
+path *pp,
 		uint64_t els_wwpn, uint64_t attached_wwpn)  {
 	struct udev_device *ctl = NULL;
@@ -263,21 +264,79 @@ static void
fpin_check_set_nvme_path_marginal(uint16_t host_num, struct path *pp
 	ctl = udev_device_get_parent_with_subsystem_devtype(pp->udev,
"nvme", NULL);
 	if (ctl == NULL) {
 		condlog(2, "%s: No parent device for ", pp->dev);
-		return;
+		return false;
 	}
 	address = udev_device_get_sysattr_value(ctl, "address");
 	if (!address) {
 		condlog(2, "%s: unable to get the address ", pp->dev);
-		return;
+		return false;
 	}
 	condlog(4, "\n address %s: dev :%s\n", address, pp->dev);
 	ret = extract_nvme_addresses_chk_path_pwwn(address, els_wwpn,
attached_wwpn);
 	if (ret <= 0)
-		return;
+		return false;
 	ret = fpin_add_marginal_dev_info(host_num, pp->dev);
 	if (ret < 0)
-		return;
+		return false;
 	fpin_path_setmarginal(pp);
+	return true;
+}
+
+static void fpin_nvme_set_rport_marginal(uint16_t host_num, uint64_t
+els_wwpn) {
+	struct udev_enumerate *udev_enum = NULL;
+	struct udev_list_entry *entry;
+
+	pthread_cleanup_push(cleanup_udev_enumerate_ptr, &udev_enum);
+	udev_enum = udev_enumerate_new(udev);
+	if (!udev_enum) {
+		condlog(0, "fpin: rport udev_enumerate_new() failed: %m");
+		goto out;
+	}
+	if (udev_enumerate_add_match_subsystem(udev_enum,
"fc_remote_ports") < 0 ||
+	    udev_enumerate_add_match_is_initialized(udev_enum) < 0 ||
+	    udev_enumerate_scan_devices(udev_enum) < 0) {
+		condlog(0, "fpin: error setting up rport enumeration:
%m");
+		goto out;
+	}
+	udev_list_entry_foreach(entry,
+				udev_enumerate_get_list_entry(udev_enum))
{
+		const char *devpath;
+		const char *rport_id, *value;
+		struct udev_device *rport_dev = NULL;
+		uint16_t rport_hostnum;
+		uint64_t rport_wwpn;
+		unsigned int unused;
+
+		pthread_cleanup_push(cleanup_udev_device_ptr, &rport_dev);
+		devpath = udev_list_entry_get_name(entry);
+		if (!devpath)
+			goto next;
+		rport_id = libmp_basename(devpath);
+		if (sscanf(rport_id, "rport-%hu:%u-%u", &rport_hostnum,
&unused,
+			   &unused) != 3 || rport_hostnum != host_num)
+			goto next;
+
+		rport_dev = udev_device_new_from_syspath(udev, devpath);
+		if (!rport_dev) {
+			condlog(0, "%s: error getting rport dev: %m",
rport_id);
+			goto next;
+		}
+		value = udev_device_get_sysattr_value(rport_dev,
"port_name");
+		if (!value) {
+			condlog(0, "%s: error getting port_name: %m",
rport_id);
+			goto next;
+		}
+
+		rport_wwpn = strtol(value, NULL, 16);
+		/* If the rport wwpn matches, set the port state to
marginal */
+		if (rport_wwpn == els_wwpn)
+			fpin_set_rport_marginal(rport_dev);
+next:
+		pthread_cleanup_pop(1);
+	}
+out:
+	pthread_cleanup_pop(1);
 }

 /*
@@ -338,6 +397,7 @@ static int  fpin_chk_wwn_setpath_marginal(uint16_t
host_num,  struct vectors *ve
 	struct multipath *mpp;
 	int i, k;
 	int ret = 0;
+	bool found_nvme = false;

 	pthread_cleanup_push(cleanup_lock, &vecs->lock);
 	lock(&vecs->lock);
@@ -348,7 +408,7 @@ static int  fpin_chk_wwn_setpath_marginal(uint16_t
host_num,  struct vectors *ve
 			continue;
 		/*checks if the bus type is nvme  and the protocol is
FC-NVMe*/
 		if ((pp->bus == SYSFS_BUS_NVME) && (pp->sg_id.proto_id ==
NVME_PROTOCOL_FC)) {
-			fpin_check_set_nvme_path_marginal(host_num, pp,
els_wwpn, attached_wwpn);
+			found_nvme =
fpin_check_set_nvme_path_marginal(host_num, pp,
+els_wwpn, attached_wwpn) || found_nvme;
 		} else if ((pp->bus == SYSFS_BUS_SCSI) &&
 			(pp->sg_id.proto_id == SCSI_PROTOCOL_FCP) &&
 			(host_num ==  pp->sg_id.host_no)) {
@@ -356,6 +416,8 @@ static int  fpin_chk_wwn_setpath_marginal(uint16_t
host_num,  struct vectors *ve
 			fpin_check_set_scsi_path_marginal(host_num, pp,
els_wwpn);
 		}
 	}
+	if (found_nvme)
+		fpin_nvme_set_rport_marginal(host_num, els_wwpn);
 	/* walk backwards because reload_and_sync_map() can remove mpp */
 	vector_foreach_slot_backwards(vecs->mpvec, mpp, i) {
 		if (mpp->fpin_must_reload) {
--
2.46.2

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