From: Jason Gunthorpe <jgg@mellanox.com>
Date: Wed, 6 May 2020 10:46:55 +0300
Subject: RDMA/cm: Pull duplicated code into cm_queue_work_unlock()
Patch-mainline: v5.8-rc1
Git-commit: e83f195aa45c1ffd73b3a950a887e41c260cf194
References: jsc#SLE-15176
While unlocking a spinlock held by the caller is a disturbing pattern,
this extensively duplicated code is even worse. Pull all the duplicates
into a function and explain the purpose of the algorithm.
The on creation side call in cm_req_handler() which is different has been
micro-optimized on the basis that the work_count == -1 during creation,
remove that and just use the normal function.
Link: https://lore.kernel.org/r/20200506074701.9775-5-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/infiniband/core/cm.c | 146 ++++++++++++-------------------------------
1 file changed, 44 insertions(+), 102 deletions(-)
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -81,8 +81,11 @@ const char *__attribute_const__ ibcm_rej
EXPORT_SYMBOL(ibcm_reject_msg);
struct cm_id_private;
+struct cm_work;
static int cm_add_one(struct ib_device *device);
static void cm_remove_one(struct ib_device *device, void *client_data);
+static void cm_process_work(struct cm_id_private *cm_id_priv,
+ struct cm_work *work);
static int cm_send_sidr_rep_locked(struct cm_id_private *cm_id_priv,
struct ib_cm_sidr_rep_param *param);
static int cm_send_dreq_locked(struct cm_id_private *cm_id_priv,
@@ -907,6 +910,35 @@ static void cm_free_work(struct cm_work
kfree(work);
}
+static void cm_queue_work_unlock(struct cm_id_private *cm_id_priv,
+ struct cm_work *work)
+{
+ bool immediate;
+
+ /*
+ * To deliver the event to the user callback we have the drop the
+ * spinlock, however, we need to ensure that the user callback is single
+ * threaded and receives events in the temporal order. If there are
+ * already events being processed then thread new events onto a list,
+ * the thread currently processing will pick them up.
+ */
+ immediate = atomic_inc_and_test(&cm_id_priv->work_count);
+ if (!immediate) {
+ list_add_tail(&work->list, &cm_id_priv->work_list);
+ /*
+ * This routine always consumes incoming reference. Once queued
+ * to the work_list then a reference is held by the thread
+ * currently running cm_process_work() and this reference is not
+ * needed.
+ */
+ cm_deref_id(cm_id_priv);
+ }
+ spin_unlock_irq(&cm_id_priv->lock);
+
+ if (immediate)
+ cm_process_work(cm_id_priv, work);
+}
+
static inline int cm_convert_to_ms(int iba_time)
{
/* approximate conversion to ms from 4.096us x 2^iba_time */
@@ -2143,9 +2175,7 @@ static int cm_req_handler(struct cm_work
/* Refcount belongs to the event, pairs with cm_process_work() */
refcount_inc(&cm_id_priv->refcount);
- atomic_inc(&cm_id_priv->work_count);
- spin_unlock_irq(&cm_id_priv->lock);
- cm_process_work(cm_id_priv, work);
+ cm_queue_work_unlock(cm_id_priv, work);
/*
* Since this ID was just created and was not made visible to other MAD
* handlers until the cm_finalize_id() above we know that the
@@ -2491,15 +2521,7 @@ static int cm_rep_handler(struct cm_work
cm_id_priv->alt_av.timeout - 1);
ib_cancel_mad(cm_id_priv->av.port->mad_agent, cm_id_priv->msg);
- ret = atomic_inc_and_test(&cm_id_priv->work_count);
- if (!ret)
- list_add_tail(&work->list, &cm_id_priv->work_list);
- spin_unlock_irq(&cm_id_priv->lock);
-
- if (ret)
- cm_process_work(cm_id_priv, work);
- else
- cm_deref_id(cm_id_priv);
+ cm_queue_work_unlock(cm_id_priv, work);
return 0;
error:
@@ -2510,7 +2532,6 @@ error:
static int cm_establish_handler(struct cm_work *work)
{
struct cm_id_private *cm_id_priv;
- int ret;
/* See comment in cm_establish about lookup. */
cm_id_priv = cm_acquire_id(work->local_id, work->remote_id);
@@ -2524,15 +2545,7 @@ static int cm_establish_handler(struct c
}
ib_cancel_mad(cm_id_priv->av.port->mad_agent, cm_id_priv->msg);
- ret = atomic_inc_and_test(&cm_id_priv->work_count);
- if (!ret)
- list_add_tail(&work->list, &cm_id_priv->work_list);
- spin_unlock_irq(&cm_id_priv->lock);
-
- if (ret)
- cm_process_work(cm_id_priv, work);
- else
- cm_deref_id(cm_id_priv);
+ cm_queue_work_unlock(cm_id_priv, work);
return 0;
out:
cm_deref_id(cm_id_priv);
@@ -2543,7 +2556,6 @@ static int cm_rtu_handler(struct cm_work
{
struct cm_id_private *cm_id_priv;
struct cm_rtu_msg *rtu_msg;
- int ret;
rtu_msg = (struct cm_rtu_msg *)work->mad_recv_wc->recv_buf.mad;
cm_id_priv = cm_acquire_id(
@@ -2566,15 +2578,7 @@ static int cm_rtu_handler(struct cm_work
cm_id_priv->id.state = IB_CM_ESTABLISHED;
ib_cancel_mad(cm_id_priv->av.port->mad_agent, cm_id_priv->msg);
- ret = atomic_inc_and_test(&cm_id_priv->work_count);
- if (!ret)
- list_add_tail(&work->list, &cm_id_priv->work_list);
- spin_unlock_irq(&cm_id_priv->lock);
-
- if (ret)
- cm_process_work(cm_id_priv, work);
- else
- cm_deref_id(cm_id_priv);
+ cm_queue_work_unlock(cm_id_priv, work);
return 0;
out:
cm_deref_id(cm_id_priv);
@@ -2767,7 +2771,6 @@ static int cm_dreq_handler(struct cm_wor
struct cm_id_private *cm_id_priv;
struct cm_dreq_msg *dreq_msg;
struct ib_mad_send_buf *msg = NULL;
- int ret;
dreq_msg = (struct cm_dreq_msg *)work->mad_recv_wc->recv_buf.mad;
cm_id_priv = cm_acquire_id(
@@ -2832,15 +2835,7 @@ static int cm_dreq_handler(struct cm_wor
}
cm_id_priv->id.state = IB_CM_DREQ_RCVD;
cm_id_priv->tid = dreq_msg->hdr.tid;
- ret = atomic_inc_and_test(&cm_id_priv->work_count);
- if (!ret)
- list_add_tail(&work->list, &cm_id_priv->work_list);
- spin_unlock_irq(&cm_id_priv->lock);
-
- if (ret)
- cm_process_work(cm_id_priv, work);
- else
- cm_deref_id(cm_id_priv);
+ cm_queue_work_unlock(cm_id_priv, work);
return 0;
unlock: spin_unlock_irq(&cm_id_priv->lock);
@@ -2852,7 +2847,6 @@ static int cm_drep_handler(struct cm_wor
{
struct cm_id_private *cm_id_priv;
struct cm_drep_msg *drep_msg;
- int ret;
drep_msg = (struct cm_drep_msg *)work->mad_recv_wc->recv_buf.mad;
cm_id_priv = cm_acquire_id(
@@ -2873,15 +2867,7 @@ static int cm_drep_handler(struct cm_wor
cm_enter_timewait(cm_id_priv);
ib_cancel_mad(cm_id_priv->av.port->mad_agent, cm_id_priv->msg);
- ret = atomic_inc_and_test(&cm_id_priv->work_count);
- if (!ret)
- list_add_tail(&work->list, &cm_id_priv->work_list);
- spin_unlock_irq(&cm_id_priv->lock);
-
- if (ret)
- cm_process_work(cm_id_priv, work);
- else
- cm_deref_id(cm_id_priv);
+ cm_queue_work_unlock(cm_id_priv, work);
return 0;
out:
cm_deref_id(cm_id_priv);
@@ -3012,7 +2998,6 @@ static int cm_rej_handler(struct cm_work
{
struct cm_id_private *cm_id_priv;
struct cm_rej_msg *rej_msg;
- int ret;
rej_msg = (struct cm_rej_msg *)work->mad_recv_wc->recv_buf.mad;
cm_id_priv = cm_acquire_rejected_id(rej_msg);
@@ -3061,15 +3046,7 @@ static int cm_rej_handler(struct cm_work
goto out;
}
- ret = atomic_inc_and_test(&cm_id_priv->work_count);
- if (!ret)
- list_add_tail(&work->list, &cm_id_priv->work_list);
- spin_unlock_irq(&cm_id_priv->lock);
-
- if (ret)
- cm_process_work(cm_id_priv, work);
- else
- cm_deref_id(cm_id_priv);
+ cm_queue_work_unlock(cm_id_priv, work);
return 0;
out:
cm_deref_id(cm_id_priv);
@@ -3179,7 +3156,7 @@ static int cm_mra_handler(struct cm_work
{
struct cm_id_private *cm_id_priv;
struct cm_mra_msg *mra_msg;
- int timeout, ret;
+ int timeout;
mra_msg = (struct cm_mra_msg *)work->mad_recv_wc->recv_buf.mad;
cm_id_priv = cm_acquire_mraed_id(mra_msg);
@@ -3239,15 +3216,7 @@ static int cm_mra_handler(struct cm_work
cm_id_priv->msg->context[1] = (void *) (unsigned long)
cm_id_priv->id.state;
- ret = atomic_inc_and_test(&cm_id_priv->work_count);
- if (!ret)
- list_add_tail(&work->list, &cm_id_priv->work_list);
- spin_unlock_irq(&cm_id_priv->lock);
-
- if (ret)
- cm_process_work(cm_id_priv, work);
- else
- cm_deref_id(cm_id_priv);
+ cm_queue_work_unlock(cm_id_priv, work);
return 0;
out:
spin_unlock_irq(&cm_id_priv->lock);
@@ -3382,15 +3351,7 @@ static int cm_lap_handler(struct cm_work
cm_id_priv->id.lap_state = IB_CM_LAP_RCVD;
cm_id_priv->tid = lap_msg->hdr.tid;
- ret = atomic_inc_and_test(&cm_id_priv->work_count);
- if (!ret)
- list_add_tail(&work->list, &cm_id_priv->work_list);
- spin_unlock_irq(&cm_id_priv->lock);
-
- if (ret)
- cm_process_work(cm_id_priv, work);
- else
- cm_deref_id(cm_id_priv);
+ cm_queue_work_unlock(cm_id_priv, work);
return 0;
unlock: spin_unlock_irq(&cm_id_priv->lock);
@@ -3402,7 +3363,6 @@ static int cm_apr_handler(struct cm_work
{
struct cm_id_private *cm_id_priv;
struct cm_apr_msg *apr_msg;
- int ret;
/* Currently Alternate path messages are not supported for
* RoCE link layer.
@@ -3437,16 +3397,7 @@ static int cm_apr_handler(struct cm_work
cm_id_priv->id.lap_state = IB_CM_LAP_IDLE;
ib_cancel_mad(cm_id_priv->av.port->mad_agent, cm_id_priv->msg);
cm_id_priv->msg = NULL;
-
- ret = atomic_inc_and_test(&cm_id_priv->work_count);
- if (!ret)
- list_add_tail(&work->list, &cm_id_priv->work_list);
- spin_unlock_irq(&cm_id_priv->lock);
-
- if (ret)
- cm_process_work(cm_id_priv, work);
- else
- cm_deref_id(cm_id_priv);
+ cm_queue_work_unlock(cm_id_priv, work);
return 0;
out:
cm_deref_id(cm_id_priv);
@@ -3457,7 +3408,6 @@ static int cm_timewait_handler(struct cm
{
struct cm_timewait_info *timewait_info;
struct cm_id_private *cm_id_priv;
- int ret;
timewait_info = container_of(work, struct cm_timewait_info, work);
spin_lock_irq(&cm.lock);
@@ -3476,15 +3426,7 @@ static int cm_timewait_handler(struct cm
goto out;
}
cm_id_priv->id.state = IB_CM_IDLE;
- ret = atomic_inc_and_test(&cm_id_priv->work_count);
- if (!ret)
- list_add_tail(&work->list, &cm_id_priv->work_list);
- spin_unlock_irq(&cm_id_priv->lock);
-
- if (ret)
- cm_process_work(cm_id_priv, work);
- else
- cm_deref_id(cm_id_priv);
+ cm_queue_work_unlock(cm_id_priv, work);
return 0;
out:
cm_deref_id(cm_id_priv);