2019-08-02 22:11:12

by Chuhong Yuan

Subject: [PATCH] net/mlx4_core: Use refcount_t for refcount

refcount_t is better for reference counters since its
implementation can prevent overflows.
So convert atomic_t ref counters to refcount_t.

Also convert refcount from 0-based to 1-based.

Signed-off-by: Chuhong Yuan <[email protected]>
---
.../ethernet/mellanox/mlx4/resource_tracker.c | 90 +++++++++----------
1 file changed, 45 insertions(+), 45 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
index 4356f3a58002..d7e26935fd76 100644
--- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
+++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
@@ -114,7 +114,7 @@ struct res_qp {
struct list_head mcg_list;
spinlock_t mcg_spl;
int local_qpn;
- atomic_t ref_count;
+ refcount_t ref_count;
u32 qpc_flags;
/* saved qp params before VST enforcement in order to restore on VGT */
u8 sched_queue;
@@ -143,7 +143,7 @@ static inline const char *mtt_states_str(enum res_mtt_states state)
struct res_mtt {
struct res_common com;
int order;
- atomic_t ref_count;
+ refcount_t ref_count;
};

enum res_mpt_states {
@@ -179,7 +179,7 @@ enum res_cq_states {
struct res_cq {
struct res_common com;
struct res_mtt *mtt;
- atomic_t ref_count;
+ refcount_t ref_count;
};

enum res_srq_states {
@@ -192,7 +192,7 @@ struct res_srq {
struct res_common com;
struct res_mtt *mtt;
struct res_cq *cq;
- atomic_t ref_count;
+ refcount_t ref_count;
};

enum res_counter_states {
@@ -1050,7 +1050,7 @@ static struct res_common *alloc_qp_tr(int id)
ret->local_qpn = id;
INIT_LIST_HEAD(&ret->mcg_list);
spin_lock_init(&ret->mcg_spl);
- atomic_set(&ret->ref_count, 0);
+ refcount_set(&ret->ref_count, 1);

return &ret->com;
}
@@ -1066,7 +1066,7 @@ static struct res_common *alloc_mtt_tr(int id, int order)
ret->com.res_id = id;
ret->order = order;
ret->com.state = RES_MTT_ALLOCATED;
- atomic_set(&ret->ref_count, 0);
+ refcount_set(&ret->ref_count, 1);

return &ret->com;
}
@@ -1110,7 +1110,7 @@ static struct res_common *alloc_cq_tr(int id)

ret->com.res_id = id;
ret->com.state = RES_CQ_ALLOCATED;
- atomic_set(&ret->ref_count, 0);
+ refcount_set(&ret->ref_count, 1);

return &ret->com;
}
@@ -1125,7 +1125,7 @@ static struct res_common *alloc_srq_tr(int id)

ret->com.res_id = id;
ret->com.state = RES_SRQ_ALLOCATED;
- atomic_set(&ret->ref_count, 0);
+ refcount_set(&ret->ref_count, 1);

return &ret->com;
}
@@ -1325,10 +1325,10 @@ static int add_res_range(struct mlx4_dev *dev, int slave, u64 base, int count,

static int remove_qp_ok(struct res_qp *res)
{
- if (res->com.state == RES_QP_BUSY || atomic_read(&res->ref_count) ||
+ if (res->com.state == RES_QP_BUSY || refcount_read(&res->ref_count) != 1 ||
!list_empty(&res->mcg_list)) {
pr_err("resource tracker: fail to remove qp, state %d, ref_count %d\n",
- res->com.state, atomic_read(&res->ref_count));
+ res->com.state, refcount_read(&res->ref_count));
return -EBUSY;
} else if (res->com.state != RES_QP_RESERVED) {
return -EPERM;
@@ -1340,11 +1340,11 @@ static int remove_qp_ok(struct res_qp *res)
static int remove_mtt_ok(struct res_mtt *res, int order)
{
if (res->com.state == RES_MTT_BUSY ||
- atomic_read(&res->ref_count)) {
+ refcount_read(&res->ref_count) != 1) {
pr_devel("%s-%d: state %s, ref_count %d\n",
__func__, __LINE__,
mtt_states_str(res->com.state),
- atomic_read(&res->ref_count));
+ refcount_read(&res->ref_count));
return -EBUSY;
} else if (res->com.state != RES_MTT_ALLOCATED)
return -EPERM;
@@ -1675,7 +1675,7 @@ static int cq_res_start_move_to(struct mlx4_dev *dev, int slave, int cqn,
} else if (state == RES_CQ_ALLOCATED) {
if (r->com.state != RES_CQ_HW)
err = -EINVAL;
- else if (atomic_read(&r->ref_count))
+ else if (refcount_read(&r->ref_count) != 1)
err = -EBUSY;
else
err = 0;
@@ -1715,7 +1715,7 @@ static int srq_res_start_move_to(struct mlx4_dev *dev, int slave, int index,
} else if (state == RES_SRQ_ALLOCATED) {
if (r->com.state != RES_SRQ_HW)
err = -EINVAL;
- else if (atomic_read(&r->ref_count))
+ else if (refcount_read(&r->ref_count) != 1)
err = -EBUSY;
} else if (state != RES_SRQ_HW || r->com.state != RES_SRQ_ALLOCATED) {
err = -EINVAL;
@@ -2808,7 +2808,7 @@ int mlx4_SW2HW_MPT_wrapper(struct mlx4_dev *dev, int slave,
goto ex_put;

if (!phys) {
- atomic_inc(&mtt->ref_count);
+ refcount_inc(&mtt->ref_count);
put_res(dev, slave, mtt->com.res_id, RES_MTT);
}

@@ -2845,7 +2845,7 @@ int mlx4_HW2SW_MPT_wrapper(struct mlx4_dev *dev, int slave,
goto ex_abort;

if (mpt->mtt)
- atomic_dec(&mpt->mtt->ref_count);
+ refcount_dec(&mpt->mtt->ref_count);

res_end_move(dev, slave, RES_MPT, id);
return 0;
@@ -3007,18 +3007,18 @@ int mlx4_RST2INIT_QP_wrapper(struct mlx4_dev *dev, int slave,
err = mlx4_DMA_wrapper(dev, slave, vhcr, inbox, outbox, cmd);
if (err)
goto ex_put_srq;
- atomic_inc(&mtt->ref_count);
+ refcount_inc(&mtt->ref_count);
qp->mtt = mtt;
- atomic_inc(&rcq->ref_count);
+ refcount_inc(&rcq->ref_count);
qp->rcq = rcq;
- atomic_inc(&scq->ref_count);
+ refcount_inc(&scq->ref_count);
qp->scq = scq;

if (scqn != rcqn)
put_res(dev, slave, scqn, RES_CQ);

if (use_srq) {
- atomic_inc(&srq->ref_count);
+ refcount_inc(&srq->ref_count);
put_res(dev, slave, srqn, RES_SRQ);
qp->srq = srq;
}
@@ -3113,7 +3113,7 @@ int mlx4_SW2HW_EQ_wrapper(struct mlx4_dev *dev, int slave,
if (err)
goto out_put;

- atomic_inc(&mtt->ref_count);
+ refcount_inc(&mtt->ref_count);
eq->mtt = mtt;
put_res(dev, slave, mtt->com.res_id, RES_MTT);
res_end_move(dev, slave, RES_EQ, res_id);
@@ -3310,7 +3310,7 @@ int mlx4_HW2SW_EQ_wrapper(struct mlx4_dev *dev, int slave,
if (err)
goto ex_put;

- atomic_dec(&eq->mtt->ref_count);
+ refcount_dec(&eq->mtt->ref_count);
put_res(dev, slave, eq->mtt->com.res_id, RES_MTT);
res_end_move(dev, slave, RES_EQ, res_id);
rem_res_range(dev, slave, res_id, 1, RES_EQ, 0);
@@ -3445,7 +3445,7 @@ int mlx4_SW2HW_CQ_wrapper(struct mlx4_dev *dev, int slave,
err = mlx4_DMA_wrapper(dev, slave, vhcr, inbox, outbox, cmd);
if (err)
goto out_put;
- atomic_inc(&mtt->ref_count);
+ refcount_inc(&mtt->ref_count);
cq->mtt = mtt;
put_res(dev, slave, mtt->com.res_id, RES_MTT);
res_end_move(dev, slave, RES_CQ, cqn);
@@ -3474,7 +3474,7 @@ int mlx4_HW2SW_CQ_wrapper(struct mlx4_dev *dev, int slave,
err = mlx4_DMA_wrapper(dev, slave, vhcr, inbox, outbox, cmd);
if (err)
goto out_move;
- atomic_dec(&cq->mtt->ref_count);
+ refcount_dec(&cq->mtt->ref_count);
res_end_move(dev, slave, RES_CQ, cqn);
return 0;

@@ -3539,9 +3539,9 @@ static int handle_resize(struct mlx4_dev *dev, int slave,
err = mlx4_DMA_wrapper(dev, slave, vhcr, inbox, outbox, cmd);
if (err)
goto ex_put1;
- atomic_dec(&orig_mtt->ref_count);
+ refcount_dec(&orig_mtt->ref_count);
put_res(dev, slave, orig_mtt->com.res_id, RES_MTT);
- atomic_inc(&mtt->ref_count);
+ refcount_inc(&mtt->ref_count);
cq->mtt = mtt;
put_res(dev, slave, mtt->com.res_id, RES_MTT);
return 0;
@@ -3627,7 +3627,7 @@ int mlx4_SW2HW_SRQ_wrapper(struct mlx4_dev *dev, int slave,
if (err)
goto ex_put_mtt;

- atomic_inc(&mtt->ref_count);
+ refcount_inc(&mtt->ref_count);
srq->mtt = mtt;
put_res(dev, slave, mtt->com.res_id, RES_MTT);
res_end_move(dev, slave, RES_SRQ, srqn);
@@ -3657,9 +3657,9 @@ int mlx4_HW2SW_SRQ_wrapper(struct mlx4_dev *dev, int slave,
err = mlx4_DMA_wrapper(dev, slave, vhcr, inbox, outbox, cmd);
if (err)
goto ex_abort;
- atomic_dec(&srq->mtt->ref_count);
+ refcount_dec(&srq->mtt->ref_count);
if (srq->cq)
- atomic_dec(&srq->cq->ref_count);
+ refcount_dec(&srq->cq->ref_count);
res_end_move(dev, slave, RES_SRQ, srqn);

return 0;
@@ -3988,11 +3988,11 @@ int mlx4_2RST_QP_wrapper(struct mlx4_dev *dev, int slave,
if (err)
goto ex_abort;

- atomic_dec(&qp->mtt->ref_count);
- atomic_dec(&qp->rcq->ref_count);
- atomic_dec(&qp->scq->ref_count);
+ refcount_dec(&qp->mtt->ref_count);
+ refcount_dec(&qp->rcq->ref_count);
+ refcount_dec(&qp->scq->ref_count);
if (qp->srq)
- atomic_dec(&qp->srq->ref_count);
+ refcount_dec(&qp->srq->ref_count);
res_end_move(dev, slave, RES_QP, qpn);
return 0;

@@ -4456,7 +4456,7 @@ int mlx4_QP_FLOW_STEERING_ATTACH_wrapper(struct mlx4_dev *dev, int slave,
if (mlx4_is_bonded(dev))
mlx4_do_mirror_rule(dev, rrule);

- atomic_inc(&rqp->ref_count);
+ refcount_inc(&rqp->ref_count);

err_put_rule:
put_res(dev, slave, vhcr->out_param, RES_FS_RULE);
@@ -4540,7 +4540,7 @@ int mlx4_QP_FLOW_STEERING_DETACH_wrapper(struct mlx4_dev *dev, int slave,
MLX4_QP_FLOW_STEERING_DETACH, MLX4_CMD_TIME_CLASS_A,
MLX4_CMD_NATIVE);
if (!err)
- atomic_dec(&rqp->ref_count);
+ refcount_dec(&rqp->ref_count);
out:
put_res(dev, slave, qpn, RES_QP);
return err;
@@ -4702,11 +4702,11 @@ static void rem_slave_qps(struct mlx4_dev *dev, int slave)
if (err)
mlx4_dbg(dev, "rem_slave_qps: failed to move slave %d qpn %d to reset\n",
slave, qp->local_qpn);
- atomic_dec(&qp->rcq->ref_count);
- atomic_dec(&qp->scq->ref_count);
- atomic_dec(&qp->mtt->ref_count);
+ refcount_dec(&qp->rcq->ref_count);
+ refcount_dec(&qp->scq->ref_count);
+ refcount_dec(&qp->mtt->ref_count);
if (qp->srq)
- atomic_dec(&qp->srq->ref_count);
+ refcount_dec(&qp->srq->ref_count);
state = RES_QP_MAPPED;
break;
default:
@@ -4768,9 +4768,9 @@ static void rem_slave_srqs(struct mlx4_dev *dev, int slave)
mlx4_dbg(dev, "rem_slave_srqs: failed to move slave %d srq %d to SW ownership\n",
slave, srqn);

- atomic_dec(&srq->mtt->ref_count);
+ refcount_dec(&srq->mtt->ref_count);
if (srq->cq)
- atomic_dec(&srq->cq->ref_count);
+ refcount_dec(&srq->cq->ref_count);
state = RES_SRQ_ALLOCATED;
break;

@@ -4805,7 +4805,7 @@ static void rem_slave_cqs(struct mlx4_dev *dev, int slave)
spin_lock_irq(mlx4_tlock(dev));
list_for_each_entry_safe(cq, tmp, cq_list, com.list) {
spin_unlock_irq(mlx4_tlock(dev));
- if (cq->com.owner == slave && !atomic_read(&cq->ref_count)) {
+ if (cq->com.owner == slave && refcount_read(&cq->ref_count) == 1) {
cqn = cq->com.res_id;
state = cq->com.from_state;
while (state != 0) {
@@ -4832,7 +4832,7 @@ static void rem_slave_cqs(struct mlx4_dev *dev, int slave)
if (err)
mlx4_dbg(dev, "rem_slave_cqs: failed to move slave %d cq %d to SW ownership\n",
slave, cqn);
- atomic_dec(&cq->mtt->ref_count);
+ refcount_dec(&cq->mtt->ref_count);
state = RES_CQ_ALLOCATED;
break;

@@ -4900,7 +4900,7 @@ static void rem_slave_mrs(struct mlx4_dev *dev, int slave)
mlx4_dbg(dev, "rem_slave_mrs: failed to move slave %d mpt %d to SW ownership\n",
slave, mptn);
if (mpt->mtt)
- atomic_dec(&mpt->mtt->ref_count);
+ refcount_dec(&mpt->mtt->ref_count);
state = RES_MPT_MAPPED;
break;
default:
@@ -5144,7 +5144,7 @@ static void rem_slave_eqs(struct mlx4_dev *dev, int slave)
if (err)
mlx4_dbg(dev, "rem_slave_eqs: failed to move slave %d eqs %d to SW ownership\n",
slave, eqn & 0x3ff);
- atomic_dec(&eq->mtt->ref_count);
+ refcount_dec(&eq->mtt->ref_count);
state = RES_EQ_RESERVED;
break;

--
2.20.1

2019-08-03 15:10:58

by Chuhong Yuan

Subject: Re: [PATCH] net/mlx4_core: Use refcount_t for refcount

Chuhong Yuan <[email protected]> 于2019年8月2日周五 下午8:10写道：
>
> refcount_t is better for reference counters since its
> implementation can prevent overflows.
> So convert atomic_t ref counters to refcount_t.
>
> Also convert refcount from 0-based to 1-based.
>

It seems that directly converting refcount from 0-based
to 1-based is infeasible.
I am sorry for this mistake.

Regards,
Chuhong

> Signed-off-by: Chuhong Yuan <[email protected]>
> ---
> .../ethernet/mellanox/mlx4/resource_tracker.c | 90 +++++++++----------
> 1 file changed, 45 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
> index 4356f3a58002..d7e26935fd76 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
> @@ -114,7 +114,7 @@ struct res_qp {
> struct list_head mcg_list;
> spinlock_t mcg_spl;
> int local_qpn;
> - atomic_t ref_count;
> + refcount_t ref_count;
> u32 qpc_flags;
> /* saved qp params before VST enforcement in order to restore on VGT */
> u8 sched_queue;
> @@ -143,7 +143,7 @@ static inline const char *mtt_states_str(enum res_mtt_states state)
> struct res_mtt {
> struct res_common com;
> int order;
> - atomic_t ref_count;
> + refcount_t ref_count;
> };
>
> enum res_mpt_states {
> @@ -179,7 +179,7 @@ enum res_cq_states {
> struct res_cq {
> struct res_common com;
> struct res_mtt *mtt;
> - atomic_t ref_count;
> + refcount_t ref_count;
> };
>
> enum res_srq_states {
> @@ -192,7 +192,7 @@ struct res_srq {
> struct res_common com;
> struct res_mtt *mtt;
> struct res_cq *cq;
> - atomic_t ref_count;
> + refcount_t ref_count;
> };
>
> enum res_counter_states {
> @@ -1050,7 +1050,7 @@ static struct res_common *alloc_qp_tr(int id)
> ret->local_qpn = id;
> INIT_LIST_HEAD(&ret->mcg_list);
> spin_lock_init(&ret->mcg_spl);
> - atomic_set(&ret->ref_count, 0);
> + refcount_set(&ret->ref_count, 1);
>
> return &ret->com;
> }
> @@ -1066,7 +1066,7 @@ static struct res_common *alloc_mtt_tr(int id, int order)
> ret->com.res_id = id;
> ret->order = order;
> ret->com.state = RES_MTT_ALLOCATED;
> - atomic_set(&ret->ref_count, 0);
> + refcount_set(&ret->ref_count, 1);
>
> return &ret->com;
> }
> @@ -1110,7 +1110,7 @@ static struct res_common *alloc_cq_tr(int id)
>
> ret->com.res_id = id;
> ret->com.state = RES_CQ_ALLOCATED;
> - atomic_set(&ret->ref_count, 0);
> + refcount_set(&ret->ref_count, 1);
>
> return &ret->com;
> }
> @@ -1125,7 +1125,7 @@ static struct res_common *alloc_srq_tr(int id)
>
> ret->com.res_id = id;
> ret->com.state = RES_SRQ_ALLOCATED;
> - atomic_set(&ret->ref_count, 0);
> + refcount_set(&ret->ref_count, 1);
>
> return &ret->com;
> }
> @@ -1325,10 +1325,10 @@ static int add_res_range(struct mlx4_dev *dev, int slave, u64 base, int count,
>
> static int remove_qp_ok(struct res_qp *res)
> {
> - if (res->com.state == RES_QP_BUSY || atomic_read(&res->ref_count) ||
> + if (res->com.state == RES_QP_BUSY || refcount_read(&res->ref_count) != 1 ||
> !list_empty(&res->mcg_list)) {
> pr_err("resource tracker: fail to remove qp, state %d, ref_count %d\n",
> - res->com.state, atomic_read(&res->ref_count));
> + res->com.state, refcount_read(&res->ref_count));
> return -EBUSY;
> } else if (res->com.state != RES_QP_RESERVED) {
> return -EPERM;
> @@ -1340,11 +1340,11 @@ static int remove_qp_ok(struct res_qp *res)
> static int remove_mtt_ok(struct res_mtt *res, int order)
> {
> if (res->com.state == RES_MTT_BUSY ||
> - atomic_read(&res->ref_count)) {
> + refcount_read(&res->ref_count) != 1) {
> pr_devel("%s-%d: state %s, ref_count %d\n",
> __func__, __LINE__,
> mtt_states_str(res->com.state),
> - atomic_read(&res->ref_count));
> + refcount_read(&res->ref_count));
> return -EBUSY;
> } else if (res->com.state != RES_MTT_ALLOCATED)
> return -EPERM;
> @@ -1675,7 +1675,7 @@ static int cq_res_start_move_to(struct mlx4_dev *dev, int slave, int cqn,
> } else if (state == RES_CQ_ALLOCATED) {
> if (r->com.state != RES_CQ_HW)
> err = -EINVAL;
> - else if (atomic_read(&r->ref_count))
> + else if (refcount_read(&r->ref_count) != 1)
> err = -EBUSY;
> else
> err = 0;
> @@ -1715,7 +1715,7 @@ static int srq_res_start_move_to(struct mlx4_dev *dev, int slave, int index,
> } else if (state == RES_SRQ_ALLOCATED) {
> if (r->com.state != RES_SRQ_HW)
> err = -EINVAL;
> - else if (atomic_read(&r->ref_count))
> + else if (refcount_read(&r->ref_count) != 1)
> err = -EBUSY;
> } else if (state != RES_SRQ_HW || r->com.state != RES_SRQ_ALLOCATED) {
> err = -EINVAL;
> @@ -2808,7 +2808,7 @@ int mlx4_SW2HW_MPT_wrapper(struct mlx4_dev *dev, int slave,
> goto ex_put;
>
> if (!phys) {
> - atomic_inc(&mtt->ref_count);
> + refcount_inc(&mtt->ref_count);
> put_res(dev, slave, mtt->com.res_id, RES_MTT);
> }
>
> @@ -2845,7 +2845,7 @@ int mlx4_HW2SW_MPT_wrapper(struct mlx4_dev *dev, int slave,
> goto ex_abort;
>
> if (mpt->mtt)
> - atomic_dec(&mpt->mtt->ref_count);
> + refcount_dec(&mpt->mtt->ref_count);
>
> res_end_move(dev, slave, RES_MPT, id);
> return 0;
> @@ -3007,18 +3007,18 @@ int mlx4_RST2INIT_QP_wrapper(struct mlx4_dev *dev, int slave,
> err = mlx4_DMA_wrapper(dev, slave, vhcr, inbox, outbox, cmd);
> if (err)
> goto ex_put_srq;
> - atomic_inc(&mtt->ref_count);
> + refcount_inc(&mtt->ref_count);
> qp->mtt = mtt;
> - atomic_inc(&rcq->ref_count);
> + refcount_inc(&rcq->ref_count);
> qp->rcq = rcq;
> - atomic_inc(&scq->ref_count);
> + refcount_inc(&scq->ref_count);
> qp->scq = scq;
>
> if (scqn != rcqn)
> put_res(dev, slave, scqn, RES_CQ);
>
> if (use_srq) {
> - atomic_inc(&srq->ref_count);
> + refcount_inc(&srq->ref_count);
> put_res(dev, slave, srqn, RES_SRQ);
> qp->srq = srq;
> }
> @@ -3113,7 +3113,7 @@ int mlx4_SW2HW_EQ_wrapper(struct mlx4_dev *dev, int slave,
> if (err)
> goto out_put;
>
> - atomic_inc(&mtt->ref_count);
> + refcount_inc(&mtt->ref_count);
> eq->mtt = mtt;
> put_res(dev, slave, mtt->com.res_id, RES_MTT);
> res_end_move(dev, slave, RES_EQ, res_id);
> @@ -3310,7 +3310,7 @@ int mlx4_HW2SW_EQ_wrapper(struct mlx4_dev *dev, int slave,
> if (err)
> goto ex_put;
>
> - atomic_dec(&eq->mtt->ref_count);
> + refcount_dec(&eq->mtt->ref_count);
> put_res(dev, slave, eq->mtt->com.res_id, RES_MTT);
> res_end_move(dev, slave, RES_EQ, res_id);
> rem_res_range(dev, slave, res_id, 1, RES_EQ, 0);
> @@ -3445,7 +3445,7 @@ int mlx4_SW2HW_CQ_wrapper(struct mlx4_dev *dev, int slave,
> err = mlx4_DMA_wrapper(dev, slave, vhcr, inbox, outbox, cmd);
> if (err)
> goto out_put;
> - atomic_inc(&mtt->ref_count);
> + refcount_inc(&mtt->ref_count);
> cq->mtt = mtt;
> put_res(dev, slave, mtt->com.res_id, RES_MTT);
> res_end_move(dev, slave, RES_CQ, cqn);
> @@ -3474,7 +3474,7 @@ int mlx4_HW2SW_CQ_wrapper(struct mlx4_dev *dev, int slave,
> err = mlx4_DMA_wrapper(dev, slave, vhcr, inbox, outbox, cmd);
> if (err)
> goto out_move;
> - atomic_dec(&cq->mtt->ref_count);
> + refcount_dec(&cq->mtt->ref_count);
> res_end_move(dev, slave, RES_CQ, cqn);
> return 0;
>
> @@ -3539,9 +3539,9 @@ static int handle_resize(struct mlx4_dev *dev, int slave,
> err = mlx4_DMA_wrapper(dev, slave, vhcr, inbox, outbox, cmd);
> if (err)
> goto ex_put1;
> - atomic_dec(&orig_mtt->ref_count);
> + refcount_dec(&orig_mtt->ref_count);
> put_res(dev, slave, orig_mtt->com.res_id, RES_MTT);
> - atomic_inc(&mtt->ref_count);
> + refcount_inc(&mtt->ref_count);
> cq->mtt = mtt;
> put_res(dev, slave, mtt->com.res_id, RES_MTT);
> return 0;
> @@ -3627,7 +3627,7 @@ int mlx4_SW2HW_SRQ_wrapper(struct mlx4_dev *dev, int slave,
> if (err)
> goto ex_put_mtt;
>
> - atomic_inc(&mtt->ref_count);
> + refcount_inc(&mtt->ref_count);
> srq->mtt = mtt;
> put_res(dev, slave, mtt->com.res_id, RES_MTT);
> res_end_move(dev, slave, RES_SRQ, srqn);
> @@ -3657,9 +3657,9 @@ int mlx4_HW2SW_SRQ_wrapper(struct mlx4_dev *dev, int slave,
> err = mlx4_DMA_wrapper(dev, slave, vhcr, inbox, outbox, cmd);
> if (err)
> goto ex_abort;
> - atomic_dec(&srq->mtt->ref_count);
> + refcount_dec(&srq->mtt->ref_count);
> if (srq->cq)
> - atomic_dec(&srq->cq->ref_count);
> + refcount_dec(&srq->cq->ref_count);
> res_end_move(dev, slave, RES_SRQ, srqn);
>
> return 0;
> @@ -3988,11 +3988,11 @@ int mlx4_2RST_QP_wrapper(struct mlx4_dev *dev, int slave,
> if (err)
> goto ex_abort;
>
> - atomic_dec(&qp->mtt->ref_count);
> - atomic_dec(&qp->rcq->ref_count);
> - atomic_dec(&qp->scq->ref_count);
> + refcount_dec(&qp->mtt->ref_count);
> + refcount_dec(&qp->rcq->ref_count);
> + refcount_dec(&qp->scq->ref_count);
> if (qp->srq)
> - atomic_dec(&qp->srq->ref_count);
> + refcount_dec(&qp->srq->ref_count);
> res_end_move(dev, slave, RES_QP, qpn);
> return 0;
>
> @@ -4456,7 +4456,7 @@ int mlx4_QP_FLOW_STEERING_ATTACH_wrapper(struct mlx4_dev *dev, int slave,
> if (mlx4_is_bonded(dev))
> mlx4_do_mirror_rule(dev, rrule);
>
> - atomic_inc(&rqp->ref_count);
> + refcount_inc(&rqp->ref_count);
>
> err_put_rule:
> put_res(dev, slave, vhcr->out_param, RES_FS_RULE);
> @@ -4540,7 +4540,7 @@ int mlx4_QP_FLOW_STEERING_DETACH_wrapper(struct mlx4_dev *dev, int slave,
> MLX4_QP_FLOW_STEERING_DETACH, MLX4_CMD_TIME_CLASS_A,
> MLX4_CMD_NATIVE);
> if (!err)
> - atomic_dec(&rqp->ref_count);
> + refcount_dec(&rqp->ref_count);
> out:
> put_res(dev, slave, qpn, RES_QP);
> return err;
> @@ -4702,11 +4702,11 @@ static void rem_slave_qps(struct mlx4_dev *dev, int slave)
> if (err)
> mlx4_dbg(dev, "rem_slave_qps: failed to move slave %d qpn %d to reset\n",
> slave, qp->local_qpn);
> - atomic_dec(&qp->rcq->ref_count);
> - atomic_dec(&qp->scq->ref_count);
> - atomic_dec(&qp->mtt->ref_count);
> + refcount_dec(&qp->rcq->ref_count);
> + refcount_dec(&qp->scq->ref_count);
> + refcount_dec(&qp->mtt->ref_count);
> if (qp->srq)
> - atomic_dec(&qp->srq->ref_count);
> + refcount_dec(&qp->srq->ref_count);
> state = RES_QP_MAPPED;
> break;
> default:
> @@ -4768,9 +4768,9 @@ static void rem_slave_srqs(struct mlx4_dev *dev, int slave)
> mlx4_dbg(dev, "rem_slave_srqs: failed to move slave %d srq %d to SW ownership\n",
> slave, srqn);
>
> - atomic_dec(&srq->mtt->ref_count);
> + refcount_dec(&srq->mtt->ref_count);
> if (srq->cq)
> - atomic_dec(&srq->cq->ref_count);
> + refcount_dec(&srq->cq->ref_count);
> state = RES_SRQ_ALLOCATED;
> break;
>
> @@ -4805,7 +4805,7 @@ static void rem_slave_cqs(struct mlx4_dev *dev, int slave)
> spin_lock_irq(mlx4_tlock(dev));
> list_for_each_entry_safe(cq, tmp, cq_list, com.list) {
> spin_unlock_irq(mlx4_tlock(dev));
> - if (cq->com.owner == slave && !atomic_read(&cq->ref_count)) {
> + if (cq->com.owner == slave && refcount_read(&cq->ref_count) == 1) {
> cqn = cq->com.res_id;
> state = cq->com.from_state;
> while (state != 0) {
> @@ -4832,7 +4832,7 @@ static void rem_slave_cqs(struct mlx4_dev *dev, int slave)
> if (err)
> mlx4_dbg(dev, "rem_slave_cqs: failed to move slave %d cq %d to SW ownership\n",
> slave, cqn);
> - atomic_dec(&cq->mtt->ref_count);
> + refcount_dec(&cq->mtt->ref_count);
> state = RES_CQ_ALLOCATED;
> break;
>
> @@ -4900,7 +4900,7 @@ static void rem_slave_mrs(struct mlx4_dev *dev, int slave)
> mlx4_dbg(dev, "rem_slave_mrs: failed to move slave %d mpt %d to SW ownership\n",
> slave, mptn);
> if (mpt->mtt)
> - atomic_dec(&mpt->mtt->ref_count);
> + refcount_dec(&mpt->mtt->ref_count);
> state = RES_MPT_MAPPED;
> break;
> default:
> @@ -5144,7 +5144,7 @@ static void rem_slave_eqs(struct mlx4_dev *dev, int slave)
> if (err)
> mlx4_dbg(dev, "rem_slave_eqs: failed to move slave %d eqs %d to SW ownership\n",
> slave, eqn & 0x3ff);
> - atomic_dec(&eq->mtt->ref_count);
> + refcount_dec(&eq->mtt->ref_count);
> state = RES_EQ_RESERVED;
> break;
>
> --
> 2.20.1
>

2019-08-03 16:52:19

by Saeed Mahameed

Subject: Re: [PATCH] net/mlx4_core: Use refcount_t for refcount

On Sat, 2019-08-03 at 00:10 +0800, Chuhong Yuan wrote:
> Chuhong Yuan <[email protected]> 于2019年8月2日周五 下午8:10写道：
> > refcount_t is better for reference counters since its
> > implementation can prevent overflows.
> > So convert atomic_t ref counters to refcount_t.
> >
> > Also convert refcount from 0-based to 1-based.
> >
>
> It seems that directly converting refcount from 0-based
> to 1-based is infeasible.
> I am sorry for this mistake.

Just curious, why not keep it 0 based and use refcout_t ?

refcount API should have the same semantics as atomic_t API .. no ?

2019-08-04 03:26:33

by Chuhong Yuan

Subject: Re: [PATCH] net/mlx4_core: Use refcount_t for refcount

Saeed Mahameed <[email protected]> 于2019年8月3日周六 上午2:38写道：
>
> On Sat, 2019-08-03 at 00:10 +0800, Chuhong Yuan wrote:
> > Chuhong Yuan <[email protected]> 于2019年8月2日周五 下午8:10写道：
> > > refcount_t is better for reference counters since its
> > > implementation can prevent overflows.
> > > So convert atomic_t ref counters to refcount_t.
> > >
> > > Also convert refcount from 0-based to 1-based.
> > >
> >
> > It seems that directly converting refcount from 0-based
> > to 1-based is infeasible.
> > I am sorry for this mistake.
>
> Just curious, why not keep it 0 based and use refcout_t ?
>
> refcount API should have the same semantics as atomic_t API .. no ?

refcount API will warn when increase a 0 refcount.
It regards this as a use-after-free.

2019-08-06 18:37:14

by Jason Gunthorpe

Subject: Re: [PATCH] net/mlx4_core: Use refcount_t for refcount

On Sat, Aug 03, 2019 at 10:42:31AM +0800, Chuhong Yuan wrote:
> Saeed Mahameed <[email protected]> 于2019年8月3日周六 上午2:38写道：
> >
> > On Sat, 2019-08-03 at 00:10 +0800, Chuhong Yuan wrote:
> > > Chuhong Yuan <[email protected]> 于2019年8月2日周五 下午8:10写道：
> > > > refcount_t is better for reference counters since its
> > > > implementation can prevent overflows.
> > > > So convert atomic_t ref counters to refcount_t.
> > > >
> > > > Also convert refcount from 0-based to 1-based.
> > > >
> > >
> > > It seems that directly converting refcount from 0-based
> > > to 1-based is infeasible.
> > > I am sorry for this mistake.
> >
> > Just curious, why not keep it 0 based and use refcout_t ?
> >
> > refcount API should have the same semantics as atomic_t API .. no ?
>
> refcount API will warn when increase a 0 refcount.
> It regards this as a use-after-free.

If this causes failures then the code is not doing atomic as a
refcount properly anyhow..

There are some cases where the atomic refcount is just a imprecise
debugging aide.

Jason