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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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Sagi Grimberg 2017-03-18 20:52:36 +02:00 committed by Jens Axboe
parent 7777bdedf3
commit 42a45274c2
2 changed files with 38 additions and 0 deletions
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28
drivers/nvme/host/fabrics.c
View File

@ -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;

10
drivers/nvme/host/fabrics.h
View File

@ -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 */