nvme: Revert: Fix controller creation races with teardown flow

commit b63de8400a6e1001b5732286cf6f5ec27799b7b4 upstream.

The indicated patch introduced a barrier in the sysfs_delete attribute
for the controller that rejects the request if the controller isn't
created. "Created" is defined as at least 1 call to nvme_start_ctrl().

This is problematic in error-injection testing.  If an error occurs on
the initial attempt to create an association and the controller enters
reconnect(s) attempts, the admin cannot delete the controller until
either there is a successful association created or ctrl_loss_tmo
times out.

Where this issue is particularly hurtful is when the "admin" is the
nvme-cli, it is performing a connection to a discovery controller, and
it is initiated via auto-connect scripts.  With the FC transport, if the
first connection attempt fails, the controller enters a normal reconnect
state but returns control to the cli thread that created the controller.
In this scenario, the cli attempts to read the discovery log via ioctl,
which fails, causing the cli to see it as an empty log and then proceeds
to delete the discovery controller. The delete is rejected and the
controller is left live. If the discovery controller reconnect then
succeeds, there is no action to delete it, and it sits live doing nothing.

Cc: <stable@vger.kernel.org> # v5.7+
Fixes: ce1518139e69 ("nvme: Fix controller creation races with teardown flow")
Signed-off-by: James Smart <james.smart@broadcom.com>
CC: Israel Rukshin <israelr@mellanox.com>
CC: Max Gurtovoy <maxg@mellanox.com>
CC: Christoph Hellwig <hch@lst.de>
CC: Keith Busch <kbusch@kernel.org>
CC: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index da82ba1896d8d9d982912b8e57ebfa9b14a7f197..f2556f0ea20dcb78ed8ab657c84f3f09ee8c924d 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3324,10 +3324,6 @@ static ssize_t nvme_sysfs_delete(struct device *dev,
 {
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
-       /* Can't delete non-created controllers */
-       if (!ctrl->created)
-               return -EBUSY;
-
        if (device_remove_file_self(dev, attr))
                nvme_delete_ctrl_sync(ctrl);
        return count;
@@ -4129,7 +4125,6 @@ void nvme_start_ctrl(struct nvme_ctrl *ctrl)
                nvme_queue_scan(ctrl);
                nvme_start_queues(ctrl);
        }
-       ctrl->created = true;
 }
 EXPORT_SYMBOL_GPL(nvme_start_ctrl);
 

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index c053aedbc55dbd573f3bd9eb061f0f3b833c8808..1db144eb74ff170092f3d1b21adc2d60d5a03d8b 100644 (file)
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -271,7 +271,6 @@ struct nvme_ctrl {
        struct nvme_command ka_cmd;
        struct work_struct fw_act_work;
        unsigned long events;
-       bool created;
 
 #ifdef CONFIG_NVME_MULTIPATH
        /* asymmetric namespace access: */