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: 87773dd56d54 ("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>

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 9a4e899d94b30a843e54f3a06e975ad632428a26..2b6c9b5160705a95d779b22aec4292904ec3b040 100644 (file)
--- 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 @@ 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);

diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index 23159dd5be184bc5db37f4d34a30653afe8b97fd..a1fd63871d17289ee61ac1e22e7f2aeed42d82cf 100644 (file)
--- 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;