[PATCH v2] IB/umem: ib_ucontext already have tgid, remove pid from ib_umem structure

Lidong Chen
2018-05-08T08:50:29Z

The userspace may invoke ibv_reg_mr and ibv_dereg_mr by different threads.
If when ibv_dereg_mr invoke and the thread which invoked ibv_reg_mr has
exited, get_pid_task will return NULL, ib_umem_release does not decrease
mm->pinned_vm. This patch fixes it by use tgid in ib_ucontext struct.

Signed-off-by: Lidong Chen <lidongchen@tencent.com>
---
[v2]
- use ib_ucontext tgid instread of tgid in ib_umem structure

drivers/infiniband/core/umem.c | 7 +------
include/rdma/ib_umem.h | 1 -
2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 9a4e899..2b6c9b5 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -119,7 +119,6 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
umem->length = size;
umem->address = addr;
umem->page_shift = PAGE_SHIFT;
- umem->pid = get_task_pid(current, PIDTYPE_PID);
/*
* We ask for writable memory if any of the following
* access flags are set. "Local write" and "remote write"
@@ -132,7 +131,6 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));

if (access & IB_ACCESS_ON_DEMAND) {
- put_pid(umem->pid);
ret = ib_umem_odp_get(context, umem, access);
if (ret) {
kfree(umem);
@@ -148,7 +146,6 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,

page_list = (struct page **) __get_free_page(GFP_KERNEL);
if (!page_list) {
- put_pid(umem->pid);
kfree(umem);
return ERR_PTR(-ENOMEM);
}
@@ -231,7 +228,6 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
if (ret < 0) {
if (need_release)
__ib_umem_release(context->device, umem, 0);
- put_pid(umem->pid);
kfree(umem);
} else
current->mm->pinned_vm = locked;
@@ -274,8 +270,7 @@ void ib_umem_release(struct ib_umem *umem)

__ib_umem_release(umem->context->device, umem, 1);

- task = get_pid_task(umem->pid, PIDTYPE_PID);
- put_pid(umem->pid);
+ task = get_pid_task(umem->context->tgid, PIDTYPE_PID);
if (!task)
goto out;
mm = get_task_mm(task);
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index 23159dd..a1fd638 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -48,7 +48,6 @@ struct ib_umem {
int writable;
int hugetlb;
struct work_struct work;
- struct pid *pid;
struct mm_struct *mm;
unsigned long diff;
struct ib_umem_odp *odp_data;
--
1.8.3.1