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IB/umem: Use the correct mm during ib_umem_release 

User-space may invoke ibv_reg_mr and ibv_dereg_mr in different threads.

If ibv_dereg_mr is called after the thread which invoked ibv_reg_mr has
exited, get_pid_task will return NULL and ib_umem_release will not
decrease mm->pinned_vm.

Instead of using threads to locate the mm, use the overall tgid from the
ib_ucontext struct instead. This matches the behavior of ODP and
disassociate in handling the mm of the process that called ibv_reg_mr.

Cc: <stable@vger.kernel.org>
Fixes: 87773dd56d ("IB: ib_umem_release() should decrement mm->pinned_vm from ib_umem_get")
Signed-off-by: Lidong Chen <lidongchen@tencent.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
zero-colors
Lidong Chen 2018-05-08 16:50:16 +08:00 committed by Jason Gunthorpe
parent 3d69191086
commit 8e907ed488
2 changed files with 1 additions and 7 deletions
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7
drivers/infiniband/core/umem.c
View File

@ -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 @@ out:
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);

1
include/rdma/ib_umem.h
View File

@ -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;