From: Parav Pandit <parav@mellanox.com>
Date: Thu, 21 Jun 2018 15:31:25 +0300
Subject: IB/core: Free GID table entry during GID deletion
Patch-mainline: v4.19-rc1
Git-commit: 59d40813328f405976774662ddb530c6e9e9df52
References: bsc#1103992 FATE#326009

If we already hold the table->lock when doing the kref_put it means we are
in a context where it is safe to do the deletion synchronously, with no
need for the work queue.

This helps to eliminate issues when GID change is requested as part of MAC
address change or bonding event change where expectation is to replace the
GID almost immediately.

Fixes: b150c3862d21 ("IB/core: Introduce GID entry reference counts")
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Parav Pandit <parav@mellanox.com>
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/cache.c |   28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

--- a/drivers/infiniband/core/cache.c
+++ b/drivers/infiniband/core/cache.c
@@ -206,7 +206,7 @@ static void schedule_free_gid(struct kre
 	queue_work(ib_wq, &entry->del_work);
 }
 
-static void free_gid_entry(struct ib_gid_table_entry *entry)
+static void free_gid_entry_locked(struct ib_gid_table_entry *entry)
 {
 	struct ib_device *device = entry->attr.device;
 	u8 port_num = entry->attr.port_num;
@@ -216,10 +216,10 @@ static void free_gid_entry(struct ib_gid
 		 device->name, port_num, entry->attr.index,
 		 entry->attr.gid.raw);
 
-	mutex_lock(&table->lock);
 	if (rdma_cap_roce_gid_table(device, port_num) &&
 	    entry->state != GID_TABLE_ENTRY_INVALID)
 		device->del_gid(&entry->attr, &entry->context);
+
 	write_lock_irq(&table->rwlock);
 
 	/*
@@ -232,13 +232,20 @@ static void free_gid_entry(struct ib_gid
 		table->data_vec[entry->attr.index] = NULL;
 	/* Now this index is ready to be allocated */
 	write_unlock_irq(&table->rwlock);
-	mutex_unlock(&table->lock);
 
 	if (entry->attr.ndev)
 		dev_put(entry->attr.ndev);
 	kfree(entry);
 }
 
+static void free_gid_entry(struct kref *kref)
+{
+	struct ib_gid_table_entry *entry =
+			container_of(kref, struct ib_gid_table_entry, kref);
+
+	free_gid_entry_locked(entry);
+}
+
 /**
  * free_gid_work - Release reference to the GID entry
  * @work: Work structure to refer to GID entry which needs to be
@@ -251,7 +258,13 @@ static void free_gid_work(struct work_st
 {
 	struct ib_gid_table_entry *entry =
 		container_of(work, struct ib_gid_table_entry, del_work);
-	free_gid_entry(entry);
+	struct ib_device *device = entry->attr.device;
+	u8 port_num = entry->attr.port_num;
+	struct ib_gid_table *table = rdma_gid_table(device, port_num);
+
+	mutex_lock(&table->lock);
+	free_gid_entry_locked(entry);
+	mutex_unlock(&table->lock);
 }
 
 static struct ib_gid_table_entry *
@@ -296,6 +309,11 @@ static void put_gid_entry(struct ib_gid_
 	kref_put(&entry->kref, schedule_free_gid);
 }
 
+static void put_gid_entry_locked(struct ib_gid_table_entry *entry)
+{
+	kref_put(&entry->kref, free_gid_entry);
+}
+
 static int add_roce_gid(struct ib_gid_table_entry *entry)
 {
 	const struct ib_gid_attr *attr = &entry->attr;
@@ -398,7 +416,7 @@ static void del_gid(struct ib_device *ib
 		table->data_vec[ix] = NULL;
 	write_unlock_irq(&table->rwlock);
 
-	put_gid_entry(entry);
+	put_gid_entry_locked(entry);
 }
 
 /* rwlock should be read locked, or lock should be held */