diff options
| author | Jack Morgenstein <jackm@dev.mellanox.co.il> | 2016-09-20 14:39:42 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-09-21 21:52:43 -0400 |
| commit | a7e1f04905e5b2b90251974dddde781301b6be37 (patch) | |
| tree | 5008a3d346e4d8b8e5aff19b8b3ab2667e1f95e7 /drivers/net/ethernet/mellanox/mlx4/mlx4.h | |
| parent | 30353bfc43a1602c020f31d95cf27182ffd23824 (diff) | |
| download | linux-a7e1f04905e5b2b90251974dddde781301b6be37.tar.bz2 | |
net/mlx4_core: Fix deadlock when switching between polling and event fw commands
When switching from polling-based fw commands to event-based fw
commands, there is a race condition which could cause a fw command
in another task to hang: that task will keep waiting for the polling
sempahore, but may never be able to acquire it. This is due to
mlx4_cmd_use_events, which "down"s the sempahore back to 0.
During driver initialization, this is not a problem, since no other
tasks which invoke FW commands are active.
However, there is a problem if the driver switches to polling mode
and then back to event mode during normal operation.
The "test_interrupts" feature does exactly that.
Running "ethtool -t <eth device> offline" causes the PF driver to
temporarily switch to polling mode, and then back to event mode.
(Note that for VF drivers, such switching is not performed).
Fix this by adding a read-write semaphore for protection when
switching between modes.
Fixes: 225c7b1feef1 ("IB/mlx4: Add a driver Mellanox ConnectX InfiniBand adapters")
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/mellanox/mlx4/mlx4.h')
| -rw-r--r-- | drivers/net/ethernet/mellanox/mlx4/mlx4.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4.h b/drivers/net/ethernet/mellanox/mlx4/mlx4.h index c9d7fc5159f2..c128ba3ef014 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4.h @@ -46,6 +46,7 @@ #include <linux/interrupt.h> #include <linux/spinlock.h> #include <net/devlink.h> +#include <linux/rwsem.h> #include <linux/mlx4/device.h> #include <linux/mlx4/driver.h> @@ -627,6 +628,7 @@ struct mlx4_cmd { struct mutex slave_cmd_mutex; struct semaphore poll_sem; struct semaphore event_sem; + struct rw_semaphore switch_sem; int max_cmds; spinlock_t context_lock; int free_head; |