From 951d01b96f174ded6180e7e4e14929ef22e7da7e Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <jgg@mellanox.com>
Date: Fri, 11 Jan 2019 19:31:24 -0700
Subject: [PATCH] IB/mlx5: Fix how advise_mr() launches async work
Work must hold a kref on the ib_device otherwise the dev pointer can
become free before the work runs. This can happen because the work is
being pushed onto the system work queue which is not flushed during driver
unregister.
Remove the bogus use of 'reg_state':
- While in uverbs the reg_state is guaranteed to always be
REGISTERED
- Testing reg_state with no locking is bogus. Use ib_device_try_get()
to get back into a region that prevents unregistration.
For now continue with a flow that is similar to the existing code.
Fixes: 813e90b1aeaa ("IB/mlx5: Add advise_mr() support")
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Moni Shoua <monis@mellanox.com>
---
drivers/infiniband/hw/mlx5/odp.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index 01e0f62006314..4ee32964e1dd9 100644
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -1595,10 +1595,12 @@ static void mlx5_ib_prefetch_mr_work(struct work_struct *work)
struct prefetch_mr_work *w =
container_of(work, struct prefetch_mr_work, work);
- if (w->dev->ib_dev.reg_state == IB_DEV_REGISTERED)
+ if (ib_device_try_get(&w->dev->ib_dev)) {
mlx5_ib_prefetch_sg_list(w->dev, w->pf_flags, w->sg_list,
w->num_sge);
-
+ ib_device_put(&w->dev->ib_dev);
+ }
+ put_device(&w->dev->ib_dev.dev);
kfree(w);
}
@@ -1617,15 +1619,13 @@ int mlx5_ib_advise_mr_prefetch(struct ib_pd *pd,
return mlx5_ib_prefetch_sg_list(dev, pf_flags, sg_list,
num_sge);
- if (dev->ib_dev.reg_state != IB_DEV_REGISTERED)
- return -ENODEV;
-
work = kvzalloc(struct_size(work, sg_list, num_sge), GFP_KERNEL);
if (!work)
return -ENOMEM;
memcpy(work->sg_list, sg_list, num_sge * sizeof(struct ib_sge));
+ get_device(&dev->ib_dev.dev);
work->dev = dev;
work->pf_flags = pf_flags;
work->num_sge = num_sge;