nvme_fc: add module to ops template to allow module references

[ Upstream commit 863fbae929c7a5b64e96b8a3ffb34a29eefb9f8f ]

In nvme-fc: it's possible to have connected active controllers
and as no references are taken on the LLDD, the LLDD can be
unloaded.  The controller would enter a reconnect state and as
long as the LLDD resumed within the reconnect timeout, the
controller would resume.  But if a namespace on the controller
is the root device, allowing the driver to unload can be problematic.
To reload the driver, it may require new io to the boot device,
and as it's no longer connected we get into a catch-22 that
eventually fails, and the system locks up.

Fix this issue by taking a module reference for every connected
controller (which is what the core layer did to the transport
module). Reference is cleared when the controller is removed.

Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 565bddcfd130d5aac3ac1057956fbe4fa6d686f5..d567035571bf2e563cf556a0ca27a03a51e68392 100644 (file)
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -342,7 +342,8 @@ nvme_fc_register_localport(struct nvme_fc_port_info *pinfo,
            !template->ls_req || !template->fcp_io ||
            !template->ls_abort || !template->fcp_abort ||
            !template->max_hw_queues || !template->max_sgl_segments ||
-           !template->max_dif_sgl_segments || !template->dma_boundary) {
+           !template->max_dif_sgl_segments || !template->dma_boundary ||
+           !template->module) {
                ret = -EINVAL;
                goto out_reghost_failed;
        }
@@ -1986,6 +1987,7 @@ nvme_fc_ctrl_free(struct kref *ref)
 {
        struct nvme_fc_ctrl *ctrl =
                container_of(ref, struct nvme_fc_ctrl, ref);
+       struct nvme_fc_lport *lport = ctrl->lport;
        unsigned long flags;
 
        if (ctrl->ctrl.tagset) {
@@ -2011,6 +2013,7 @@ nvme_fc_ctrl_free(struct kref *ref)
        if (ctrl->ctrl.opts)
                nvmf_free_options(ctrl->ctrl.opts);
        kfree(ctrl);
+       module_put(lport->ops->module);
 }
 
 static void
@@ -3040,10 +3043,15 @@ nvme_fc_init_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
                goto out_fail;
        }
 
+       if (!try_module_get(lport->ops->module)) {
+               ret = -EUNATCH;
+               goto out_free_ctrl;
+       }
+
        idx = ida_simple_get(&nvme_fc_ctrl_cnt, 0, 0, GFP_KERNEL);
        if (idx < 0) {
                ret = -ENOSPC;
-               goto out_free_ctrl;
+               goto out_mod_put;
        }
 
        ctrl->ctrl.opts = opts;
@@ -3185,6 +3193,8 @@ out_free_queues:
 out_free_ida:
        put_device(ctrl->dev);
        ida_simple_remove(&nvme_fc_ctrl_cnt, ctrl->cnum);
+out_mod_put:
+       module_put(lport->ops->module);
 out_free_ctrl:
        kfree(ctrl);
 out_fail:

diff --git a/drivers/nvme/target/fcloop.c b/drivers/nvme/target/fcloop.c
index 291f4121f516ad887f7f842761e92d3ab486196b..f0536d341f2f2a347c54216c971e824d8472648a 100644 (file)
--- a/drivers/nvme/target/fcloop.c
+++ b/drivers/nvme/target/fcloop.c
@@ -825,6 +825,7 @@ fcloop_targetport_delete(struct nvmet_fc_target_port *targetport)
 #define FCLOOP_DMABOUND_4G             0xFFFFFFFF
 
 static struct nvme_fc_port_template fctemplate = {
+       .module                 = THIS_MODULE,
        .localport_delete       = fcloop_localport_delete,
        .remoteport_delete      = fcloop_remoteport_delete,
        .create_queue           = fcloop_create_queue,

diff --git a/drivers/scsi/lpfc/lpfc_nvme.c b/drivers/scsi/lpfc/lpfc_nvme.c
index f73726e55e44d257a8f4e41a92e8325b892af5bc..6c355d87c709d19074e850f2c6eaad0d4bc6298d 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_nvme.c
+++ b/drivers/scsi/lpfc/lpfc_nvme.c
@@ -1903,6 +1903,8 @@ lpfc_nvme_fcp_abort(struct nvme_fc_local_port *pnvme_lport,
 
 /* Declare and initialization an instance of the FC NVME template. */
 static struct nvme_fc_port_template lpfc_nvme_template = {
+       .module = THIS_MODULE,
+
        /* initiator-based functions */
        .localport_delete  = lpfc_nvme_localport_delete,
        .remoteport_delete = lpfc_nvme_remoteport_delete,

diff --git a/drivers/scsi/qla2xxx/qla_nvme.c b/drivers/scsi/qla2xxx/qla_nvme.c
index 5590d6e8b57624404df0cb481ab134f2e3374a5d..db367e428095da84334b93e7e5c267003d026e87 100644 (file)
--- a/drivers/scsi/qla2xxx/qla_nvme.c
+++ b/drivers/scsi/qla2xxx/qla_nvme.c
@@ -560,6 +560,7 @@ static void qla_nvme_remoteport_delete(struct nvme_fc_remote_port *rport)
 }
 
 static struct nvme_fc_port_template qla_nvme_fc_transport = {
+       .module = THIS_MODULE,
        .localport_delete = qla_nvme_localport_delete,
        .remoteport_delete = qla_nvme_remoteport_delete,
        .create_queue   = qla_nvme_alloc_queue,

diff --git a/include/linux/nvme-fc-driver.h b/include/linux/nvme-fc-driver.h
index 496ff759f84c69c8216315570c6ef78ae347582b..2f3ae41c212dccbcfb3e31d3d21b8121228546db 100644 (file)
--- a/include/linux/nvme-fc-driver.h
+++ b/include/linux/nvme-fc-driver.h
@@ -282,6 +282,8 @@ struct nvme_fc_remote_port {
  *
  * Host/Initiator Transport Entrypoints/Parameters:
  *
+ * @module:  The LLDD module using the interface
+ *
  * @localport_delete:  The LLDD initiates deletion of a localport via
  *       nvme_fc_deregister_localport(). However, the teardown is
  *       asynchronous. This routine is called upon the completion of the
@@ -395,6 +397,8 @@ struct nvme_fc_remote_port {
  *       Value is Mandatory. Allowed to be zero.
  */
 struct nvme_fc_port_template {
+       struct module   *module;
+
        /* initiator-based functions */
        void    (*localport_delete)(struct nvme_fc_local_port *);
        void    (*remoteport_delete)(struct nvme_fc_remote_port *);