alistair23-linux/drivers/infiniband/core/restrack.c
Leon Romanovsky 03286030ac RDMA/restrack: Remove ambiguity in resource track clean logic
The restrack clean routine had simple, but powerful WARN_ON check
to see if all resources are cleared prior to releasing device.

The WARN_ON check performed very well, but lack of information
which device caused to resource leak, the object type and origin
made debug to be fun and challenging at the same time.

The fact that all dumps were the same because restrack_clean() is
called in dealloc() didn't help either.

So let's fix spelling error and convert WARN_ON to be more debug
friendly. The dmesg cut below gives example of how the output
will look output for the case fixed in patch [1]

[  438.421372] restrack: ------------[ cut here ]------------
[  438.423448] restrack: BUG: RESTRACK detected leak of resources on mlx5_2
[  438.425600] restrack: Kernel PD object allocated by mlx5_ib is not freed
[  438.427753] restrack: Kernel CQ object allocated by mlx5_ib is not freed
[  438.429660] restrack: ------------[ cut here ]------------

[1] https://patchwork.kernel.org/patch/10298695/

Cc: Michal Kalderon <Michal.Kalderon@cavium.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-03-22 12:42:48 -06:00

223 lines
5.1 KiB
C

/* SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause) */
/*
* Copyright (c) 2017-2018 Mellanox Technologies. All rights reserved.
*/
#include <rdma/rdma_cm.h>
#include <rdma/ib_verbs.h>
#include <rdma/restrack.h>
#include <linux/mutex.h>
#include <linux/sched/task.h>
#include <linux/pid_namespace.h>
#include "cma_priv.h"
void rdma_restrack_init(struct rdma_restrack_root *res)
{
init_rwsem(&res->rwsem);
}
static const char *type2str(enum rdma_restrack_type type)
{
static const char * const names[RDMA_RESTRACK_MAX] = {
[RDMA_RESTRACK_PD] = "PD",
[RDMA_RESTRACK_CQ] = "CQ",
[RDMA_RESTRACK_QP] = "QP",
[RDMA_RESTRACK_CM_ID] = "CM_ID",
[RDMA_RESTRACK_MR] = "MR",
};
return names[type];
};
void rdma_restrack_clean(struct rdma_restrack_root *res)
{
struct rdma_restrack_entry *e;
char buf[TASK_COMM_LEN];
struct ib_device *dev;
const char *owner;
int bkt;
if (hash_empty(res->hash))
return;
dev = container_of(res, struct ib_device, res);
pr_err("restrack: %s", CUT_HERE);
pr_err("restrack: BUG: RESTRACK detected leak of resources on %s\n",
dev->name);
hash_for_each(res->hash, bkt, e, node) {
if (rdma_is_kernel_res(e)) {
owner = e->kern_name;
} else {
/*
* There is no need to call get_task_struct here,
* because we can be here only if there are more
* get_task_struct() call than put_task_struct().
*/
get_task_comm(buf, e->task);
owner = buf;
}
pr_err("restrack: %s %s object allocated by %s is not freed\n",
rdma_is_kernel_res(e) ? "Kernel" : "User",
type2str(e->type), owner);
}
pr_err("restrack: %s", CUT_HERE);
}
int rdma_restrack_count(struct rdma_restrack_root *res,
enum rdma_restrack_type type,
struct pid_namespace *ns)
{
struct rdma_restrack_entry *e;
u32 cnt = 0;
down_read(&res->rwsem);
hash_for_each_possible(res->hash, e, node, type) {
if (ns == &init_pid_ns ||
(!rdma_is_kernel_res(e) &&
ns == task_active_pid_ns(e->task)))
cnt++;
}
up_read(&res->rwsem);
return cnt;
}
EXPORT_SYMBOL(rdma_restrack_count);
static void set_kern_name(struct rdma_restrack_entry *res)
{
struct ib_pd *pd;
switch (res->type) {
case RDMA_RESTRACK_QP:
pd = container_of(res, struct ib_qp, res)->pd;
if (!pd) {
WARN_ONCE(true, "XRC QPs are not supported\n");
/* Survive, despite the programmer's error */
res->kern_name = " ";
}
break;
case RDMA_RESTRACK_MR:
pd = container_of(res, struct ib_mr, res)->pd;
break;
default:
/* Other types set kern_name directly */
pd = NULL;
break;
}
if (pd)
res->kern_name = pd->res.kern_name;
}
static struct ib_device *res_to_dev(struct rdma_restrack_entry *res)
{
switch (res->type) {
case RDMA_RESTRACK_PD:
return container_of(res, struct ib_pd, res)->device;
case RDMA_RESTRACK_CQ:
return container_of(res, struct ib_cq, res)->device;
case RDMA_RESTRACK_QP:
return container_of(res, struct ib_qp, res)->device;
case RDMA_RESTRACK_CM_ID:
return container_of(res, struct rdma_id_private,
res)->id.device;
case RDMA_RESTRACK_MR:
return container_of(res, struct ib_mr, res)->device;
default:
WARN_ONCE(true, "Wrong resource tracking type %u\n", res->type);
return NULL;
}
}
static bool res_is_user(struct rdma_restrack_entry *res)
{
switch (res->type) {
case RDMA_RESTRACK_PD:
return container_of(res, struct ib_pd, res)->uobject;
case RDMA_RESTRACK_CQ:
return container_of(res, struct ib_cq, res)->uobject;
case RDMA_RESTRACK_QP:
return container_of(res, struct ib_qp, res)->uobject;
case RDMA_RESTRACK_CM_ID:
return !res->kern_name;
case RDMA_RESTRACK_MR:
return container_of(res, struct ib_mr, res)->pd->uobject;
default:
WARN_ONCE(true, "Wrong resource tracking type %u\n", res->type);
return false;
}
}
void rdma_restrack_add(struct rdma_restrack_entry *res)
{
struct ib_device *dev = res_to_dev(res);
if (!dev)
return;
if (res->type != RDMA_RESTRACK_CM_ID || !res_is_user(res))
res->task = NULL;
if (res_is_user(res)) {
if (!res->task)
rdma_restrack_set_task(res, current);
res->kern_name = NULL;
} else {
set_kern_name(res);
}
kref_init(&res->kref);
init_completion(&res->comp);
res->valid = true;
down_write(&dev->res.rwsem);
hash_add(dev->res.hash, &res->node, res->type);
up_write(&dev->res.rwsem);
}
EXPORT_SYMBOL(rdma_restrack_add);
int __must_check rdma_restrack_get(struct rdma_restrack_entry *res)
{
return kref_get_unless_zero(&res->kref);
}
EXPORT_SYMBOL(rdma_restrack_get);
static void restrack_release(struct kref *kref)
{
struct rdma_restrack_entry *res;
res = container_of(kref, struct rdma_restrack_entry, kref);
complete(&res->comp);
}
int rdma_restrack_put(struct rdma_restrack_entry *res)
{
return kref_put(&res->kref, restrack_release);
}
EXPORT_SYMBOL(rdma_restrack_put);
void rdma_restrack_del(struct rdma_restrack_entry *res)
{
struct ib_device *dev;
if (!res->valid)
return;
dev = res_to_dev(res);
if (!dev)
return;
rdma_restrack_put(res);
wait_for_completion(&res->comp);
down_write(&dev->res.rwsem);
hash_del(&res->node);
res->valid = false;
if (res->task)
put_task_struct(res->task);
up_write(&dev->res.rwsem);
}
EXPORT_SYMBOL(rdma_restrack_del);