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SubjectRe: [PATCH rdma-next 1/5] RDMA/hns: Implement the disassociate_ucontext API
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On 2018/5/23 4:21, Jason Gunthorpe wrote:
> On Sat, May 19, 2018 at 04:24:40PM +0800, Wei Hu (Xavier) wrote:
>>
>> On 2018/5/17 23:00, Jason Gunthorpe wrote:
>>> On Thu, May 17, 2018 at 04:02:49PM +0800, Wei Hu (Xavier) wrote:
>>>> This patch Implements the IB core disassociate_ucontext API.
>>>>
>>>> Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
>>>> drivers/infiniband/hw/hns/hns_roce_main.c | 36 +++++++++++++++++++++++++++++++
>>>> 1 file changed, 36 insertions(+)
>>>>
>>>> diff --git a/drivers/infiniband/hw/hns/hns_roce_main.c b/drivers/infiniband/hw/hns/hns_roce_main.c
>>>> index 96fb6a9..7fafe9d 100644
>>>> +++ b/drivers/infiniband/hw/hns/hns_roce_main.c
>>>> @@ -33,6 +33,9 @@
>>>> #include <linux/acpi.h>
>>>> #include <linux/of_platform.h>
>>>> #include <linux/module.h>
>>>> +#include <linux/sched.h>
>>>> +#include <linux/sched/mm.h>
>>>> +#include <linux/sched/task.h>
>>>> #include <rdma/ib_addr.h>
>>>> #include <rdma/ib_smi.h>
>>>> #include <rdma/ib_user_verbs.h>
>>>> @@ -422,6 +425,38 @@ static int hns_roce_port_immutable(struct ib_device *ib_dev, u8 port_num,
>>>> return 0;
>>>> }
>>>>
>>>> +static void hns_roce_disassociate_ucontext(struct ib_ucontext *ibcontext)
>>>> +{
>>>> + struct task_struct *process;
>>>> + struct mm_struct *mm;
>>>> +
>>>> + process = get_pid_task(ibcontext->tgid, PIDTYPE_PID);
>>>> + if (!process)
>>>> + return;
>>>> +
>>>> + mm = get_task_mm(process);
>>>> + if (!mm) {
>>>> + pr_info("no mm, disassociate ucontext is pending task termination\n");
>>>> + while (1) {
>>>> + put_task_struct(process);
>>>> + usleep_range(1000, 2000);
>>>> + process = get_pid_task(ibcontext->tgid, PIDTYPE_PID);
>>>> + if (!process || process->state == TASK_DEAD) {
>>>> + pr_info("disassociate ucontext done, task was terminated\n");
>>>> + /* if task was dead, need to release the task
>>>> + * struct.
>>>> + */
>>>> + if (process)
>>>> + put_task_struct(process);
>>>> + return;
>>>> + }
>>>> + }
>>>> + }
>>> I don't want to see this boilerplate code copied into every
>>> driver. Hoist it into the core code, have the disassociate driver callback
>>> accept a mm_struct parameter, and refactor the other drivers using this.
>> When the userspace RDMA application process is suspended for some reason
>> without executing ibv_close_device function,
>> There will be calltrace as follows when rmmod roce kernel driver ko in
>> the current version.
>> It looks like a common problem to every driver and the code segment
>> above is suitable for every driver.
>> Pardon me for asking, but if you have any plan to do this?
> My plan is to ask you to do it :)
Hi, Jason
I will pull this patch out of the series and send V2.
We will think how to hoist it into the core code later.
Thanks

Regards
Wei Hu
> Jason
>
> .
>


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