On 18/04/2018 4:31 PM, Zhu Yanjun wrote:
While a faulty cable is used or HCA firmware error, HCA device will be offline. When the driver is accessing this offline device, the following call trace will pop out. " ... [<ffffffff816e4842>] dump_stack+0x63/0x81 [<ffffffff816e459e>] panic+0xcc/0x21b [<ffffffffa03e5f8a>] mlx4_enter_error_state+0xba/0xf0 [mlx4_core] [<ffffffffa03e7298>] mlx4_cmd_reset_flow+0x38/0x60 [mlx4_core] [<ffffffffa03e7381>] mlx4_cmd_poll+0xc1/0x2e0 [mlx4_core] [<ffffffffa03e9f00>] __mlx4_cmd+0xb0/0x160 [mlx4_core] [<ffffffffa0406934>] mlx4_SENSE_PORT+0x54/0xd0 [mlx4_core] [<ffffffffa03f5f54>] mlx4_dev_cap+0x4a4/0xb50 [mlx4_core] ... " In the above call trace, the function mlx4_cmd_poll calls the function mlx4_cmd_post to access the HCA while HCA is offline. Then mlx4_cmd_post returns an error -EIO. Per -EIO, the function mlx4_cmd_poll calls mlx4_cmd_reset_flow to reset HCA. And the above call trace pops out. This is not reasonable. Since HCA device is offline when it is being accessed, it should not be reset again. In this patch, since HCA is offline, the function mlx4_cmd_post returns an error -EINVAL. Per -EINVAL, the function mlx4_cmd_poll directly returns instead of resetting HCA. CC: Srinivas Eeda <srinivas.eeda@xxxxxxxxxx> CC: Junxiao Bi <junxiao.bi@xxxxxxxxxx> Suggested-by: Håkon Bugge <haakon.bugge@xxxxxxxxxx> Suggested-by: Tariq Toukan <tariqt@xxxxxxxxxxxx> Signed-off-by: Zhu Yanjun <yanjun.zhu@xxxxxxxxxx> --- V1->V2: Follow Tariq's advice, avoid the disturbance from other returned errors. Since the returned values from the function mlx4_cmd_post are -EIO and -EINVAL, to -EIO, the HCA device should be reset. To -EINVAL, that means that the function mlx4_cmd_post is accessing an offline device. It is not necessary to reset HCA. Go to label out directly. --- drivers/net/ethernet/mellanox/mlx4/cmd.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
Reviewed-by: Tariq Toukan <tariqt@xxxxxxxxxxxx> Thanks Zhu. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
