linux-kernel - [PATCH v4 3/5] lib: logic_pio: Add logic_pio_unregister

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Date:   Tue, 30 Jul 2019 21:29:54 +0800
From:   John Garry <john.garry@...wei.com>
To:     <xuwei5@...wei.com>
CC:     <bhelgaas@...gle.com>, <linuxarm@...wei.com>,
        <linux-kernel@...r.kernel.org>, <arnd@...db.de>, <olof@...om.net>,
        <stable@...r.kernel.org>, John Garry <john.garry@...wei.com>
Subject: [PATCH v4 3/5] lib: logic_pio: Add logic_pio_unregister_range()

Add a function to unregister a logical PIO range.

Logical PIO space can still be leaked when unregistering certain
LOGIC_PIO_CPU_MMIO regions, but this acceptable for now since there are no
callers to unregister LOGIC_PIO_CPU_MMIO regions, and the logical PIO
region allocation scheme would need significant work to improve this.

Cc: stable@...r.kernel.org
Signed-off-by: John Garry <john.garry@...wei.com>
---
 include/linux/logic_pio.h |  1 +
 lib/logic_pio.c           | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/logic_pio.h b/include/linux/logic_pio.h
index cbd9d8495690..88e1e6304a71 100644
--- a/include/linux/logic_pio.h
+++ b/include/linux/logic_pio.h
@@ -117,6 +117,7 @@ struct logic_pio_hwaddr *find_io_range_by_fwnode(struct fwnode_handle *fwnode);
 unsigned long logic_pio_trans_hwaddr(struct fwnode_handle *fwnode,
 			resource_size_t hw_addr, resource_size_t size);
 int logic_pio_register_range(struct logic_pio_hwaddr *newrange);
+void logic_pio_unregister_range(struct logic_pio_hwaddr *range);
 resource_size_t logic_pio_to_hwaddr(unsigned long pio);
 unsigned long logic_pio_trans_cpuaddr(resource_size_t hw_addr);
 
diff --git a/lib/logic_pio.c b/lib/logic_pio.c
index d0165c88f705..905027574e5d 100644
--- a/lib/logic_pio.c
+++ b/lib/logic_pio.c
@@ -98,6 +98,20 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
 	return ret;
 }
 
+/**
+ * logic_pio_unregister_range - unregister a logical PIO range for a host
+ * @range: pointer to the IO range which has been already registered.
+ *
+ * Unregister a previously-registered IO range node.
+ */
+void logic_pio_unregister_range(struct logic_pio_hwaddr *range)
+{
+	mutex_lock(&io_range_mutex);
+	list_del_rcu(&range->list);
+	mutex_unlock(&io_range_mutex);
+	synchronize_rcu();
+}
+
 /**
  * find_io_range_by_fwnode - find logical PIO range for given FW node
  * @fwnode: FW node handle associated with logical PIO range
-- 
2.17.1