Commit 42a45274 authored by Sagi Grimberg's avatar Sagi Grimberg Committed by Jens Axboe
Browse files

nvme-fabrics: Allow ctrl loss timeout configuration 



When a host sense that its controller session is damaged,
it tries to re-establish it periodically (reconnect every
reconnect_delay). It may very well be that the controller
is gone and never coming back, in this case the host will
try to reconnect forever.

Add a ctrl_loss_tmo to bound the number of reconnect attempts
to a specific controller (default to a reasonable 10 minutes).
The timeout configuration is actually translated into number of
reconnect attempts and not a schedule on its own but rather
divided with reconnect_delay. This is useful to prevent
racing flows of remove and reconnect, and it doesn't really
matter if we remove slightly sooner than what the user requested.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarSagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 7777bded

drivers/nvme/host/fabrics.c

+28 −0
Original line number Diff line number Diff line
@@ -471,6 +471,16 @@ int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid) 
}

EXPORT_SYMBOL_GPL(nvmf_connect_io_queue);



bool nvmf_should_reconnect(struct nvme_ctrl *ctrl)

{

	if (ctrl->opts->max_reconnects != -1 &&

	    ctrl->opts->nr_reconnects < ctrl->opts->max_reconnects)

		return true;



	return false;

}

EXPORT_SYMBOL_GPL(nvmf_should_reconnect);



/**

 * nvmf_register_transport() - NVMe Fabrics Library registration function.

 * @ops:	Transport ops instance to be registered to the
@@ -533,6 +543,7 @@ static const match_table_t opt_tokens = { 
	{ NVMF_OPT_QUEUE_SIZE,		"queue_size=%d"		},

	{ NVMF_OPT_NR_IO_QUEUES,	"nr_io_queues=%d"	},

	{ NVMF_OPT_RECONNECT_DELAY,	"reconnect_delay=%d"	},

	{ NVMF_OPT_CTRL_LOSS_TMO,	"ctrl_loss_tmo=%d"	},

	{ NVMF_OPT_KATO,		"keep_alive_tmo=%d"	},

	{ NVMF_OPT_HOSTNQN,		"hostnqn=%s"		},

	{ NVMF_OPT_HOST_TRADDR,		"host_traddr=%s"	},
@@ -546,6 +557,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts, 
	char *options, *o, *p;

	int token, ret = 0;

	size_t nqnlen  = 0;

	int ctrl_loss_tmo = NVMF_DEF_CTRL_LOSS_TMO;



	/* Set defaults */

	opts->queue_size = NVMF_DEF_QUEUE_SIZE;
@@ -655,6 +667,16 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts, 
			}

			opts->kato = token;

			break;

		case NVMF_OPT_CTRL_LOSS_TMO:

			if (match_int(args, &token)) {

				ret = -EINVAL;

				goto out;

			}



			if (token < 0)

				pr_warn("ctrl_loss_tmo < 0 will reconnect forever\n");

			ctrl_loss_tmo = token;

			break;

		case NVMF_OPT_HOSTNQN:

			if (opts->host) {

				pr_err("hostnqn already user-assigned: %s\n",
@@ -710,6 +732,12 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts, 
		}

	}



	if (ctrl_loss_tmo < 0)

		opts->max_reconnects = -1;

	else

		opts->max_reconnects = DIV_ROUND_UP(ctrl_loss_tmo,

						opts->reconnect_delay);



	if (!opts->host) {

		kref_get(&nvmf_default_host->ref);

		opts->host = nvmf_default_host;

drivers/nvme/host/fabrics.h

+10 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
#define NVMF_MAX_QUEUE_SIZE	1024

#define NVMF_DEF_QUEUE_SIZE	128

#define NVMF_DEF_RECONNECT_DELAY	10

/* default to 600 seconds of reconnect attempts before giving up */

#define NVMF_DEF_CTRL_LOSS_TMO		600



/*

 * Define a host as seen by the target.  We allocate one at boot, but also
@@ -53,6 +55,7 @@ enum { 
	NVMF_OPT_HOSTNQN	= 1 << 8,

	NVMF_OPT_RECONNECT_DELAY = 1 << 9,

	NVMF_OPT_HOST_TRADDR	= 1 << 10,

	NVMF_OPT_CTRL_LOSS_TMO	= 1 << 11,

};



/**
@@ -77,6 +80,10 @@ enum { 
 * @discovery_nqn: indicates if the subsysnqn is the well-known discovery NQN.

 * @kato:	Keep-alive timeout.

 * @host:	Virtual NVMe host, contains the NQN and Host ID.

 * @nr_reconnects: number of reconnect attempted since the last ctrl failure

 * @max_reconnects: maximum number of allowed reconnect attempts before removing

 *              the controller, (-1) means reconnect forever, zero means remove

 *              immediately;

 */

struct nvmf_ctrl_options {

	unsigned		mask;
@@ -91,6 +98,8 @@ struct nvmf_ctrl_options { 
	bool			discovery_nqn;

	unsigned int		kato;

	struct nvmf_host	*host;

	int			nr_reconnects;

	int			max_reconnects;

};



/*
@@ -133,5 +142,6 @@ void nvmf_unregister_transport(struct nvmf_transport_ops *ops); 
void nvmf_free_options(struct nvmf_ctrl_options *opts);

const char *nvmf_get_subsysnqn(struct nvme_ctrl *ctrl);

int nvmf_get_address(struct nvme_ctrl *ctrl, char *buf, int size);

bool nvmf_should_reconnect(struct nvme_ctrl *ctrl);



#endif /* _NVME_FABRICS_H */

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