nvme: expand nvmf_check_if_ready checks

The nvmf_check_if_ready() checks that were added are very simplistic.
As such, the routine allows a lot of cases to fail ios during windows
of reset or re-connection. In cases where there are not multi-path
options present, the error goes back to the callee - the filesystem
or application. Not good.

The common routine was rewritten and calling syntax slightly expanded
so that per-transport is_ready routines don't need to be present.
The transports now call the routine directly. The routine is now a
fabrics routine rather than an inline function.

The routine now looks at controller state to decide the action to
take. Some states mandate io failure. Others define the condition where
a command can be accepted.  When the decision is unclear, a generic
queue-or-reject check is made to look for failfast or multipath ios and
only fails the io if it is so marked. Otherwise, the io will be queued
and wait for the controller state to resolve.

Admin commands issued via ioctl share a live admin queue with commands
from the transport for controller init. The ioctls could be intermixed
with the initialization commands. It's possible for the ioctl cmd to
be issued prior to the controller being enabled. To block this, the
ioctl admin commands need to be distinguished from admin commands used
for controller init. Added a USERCMD nvme_req(req)->rq_flags bit to
reflect this division and set it on ioctls requests.  As the
nvmf_check_if_ready() routine is called prior to nvme_setup_cmd(),
ensure that commands allocated by the ioctl path (actually anything
in core.c) preps the nvme_req(req) before starting the io. This will
preserve the USERCMD flag during execution and/or retry.

Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.e>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 79 insertions, 0 deletions

diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 3583f9492a45..124c458806df 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -536,6 +536,85 @@ static struct nvmf_transport_ops *nvmf_lookup_transport(
 	return NULL;
 }
 
+blk_status_t nvmf_check_if_ready(struct nvme_ctrl *ctrl, struct request *rq,
+		bool queue_live, bool is_connected)
+{
+	struct nvme_command *cmd = nvme_req(rq)->cmd;
+
+	if (likely(ctrl->state == NVME_CTRL_LIVE && is_connected))
+		return BLK_STS_OK;
+
+	switch (ctrl->state) {
+	case NVME_CTRL_DELETING:
+		goto reject_io;
+
+	case NVME_CTRL_NEW:
+	case NVME_CTRL_CONNECTING:
+		if (!is_connected)
+			/*
+			 * This is the case of starting a new
+			 * association but connectivity was lost
+			 * before it was fully created. We need to
+			 * error the commands used to initialize the
+			 * controller so the reconnect can go into a
+			 * retry attempt. The commands should all be
+			 * marked REQ_FAILFAST_DRIVER, which will hit
+			 * the reject path below. Anything else will
+			 * be queued while the state settles.
+			 */
+			goto reject_or_queue_io;
+
+		if ((queue_live &&
+		     !(nvme_req(rq)->flags & NVME_REQ_USERCMD)) ||
+		    (!queue_live && blk_rq_is_passthrough(rq) &&
+		     cmd->common.opcode == nvme_fabrics_command &&
+		     cmd->fabrics.fctype == nvme_fabrics_type_connect))
+			/*
+			 * If queue is live, allow only commands that
+			 * are internally generated pass through. These
+			 * are commands on the admin queue to initialize
+			 * the controller. This will reject any ioctl
+			 * admin cmds received while initializing.
+			 *
+			 * If the queue is not live, allow only a
+			 * connect command. This will reject any ioctl
+			 * admin cmd as well as initialization commands
+			 * if the controller reverted the queue to non-live.
+			 */
+			return BLK_STS_OK;
+
+		/*
+		 * fall-thru to the reject_or_queue_io clause
+		 */
+		break;
+
+	/* these cases fall-thru
+	 * case NVME_CTRL_LIVE:
+	 * case NVME_CTRL_RESETTING:
+	 */
+	default:
+		break;
+	}
+
+reject_or_queue_io:
+	/*
+	 * Any other new io is something we're not in a state to send
+	 * to the device. Default action is to busy it and retry it
+	 * after the controller state is recovered. However, anything
+	 * marked for failfast or nvme multipath is immediately failed.
+	 * Note: commands used to initialize the controller will be
+	 *  marked for failfast.
+	 * Note: nvme cli/ioctl commands are marked for failfast.
+	 */
+	if (!blk_noretry_request(rq) && !(rq->cmd_flags & REQ_NVME_MPATH))
+		return BLK_STS_RESOURCE;
+
+reject_io:
+	nvme_req(rq)->status = NVME_SC_ABORT_REQ;
+	return BLK_STS_IOERR;
+}
+EXPORT_SYMBOL_GPL(nvmf_check_if_ready);
+
 static const match_table_t opt_tokens = {
 	{ NVMF_OPT_TRANSPORT,		"transport=%s"		},
 	{ NVMF_OPT_TRADDR,		"traddr=%s"		},