From 84e5acb76dacb8ebd648a86a53907ce0dd616534 Mon Sep 17 00:00:00 2001
From: Matthew Wilcox <willy@infradead.org>
Date: Fri, 26 Oct 2018 14:41:29 -0400
Subject: [PATCH] XArray: Add xa_store_bh() and xa_store_irq()

These convenience wrappers disable interrupts while taking the spinlock.
A number of drivers would otherwise have to open-code these functions.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
---
 Documentation/core-api/xarray.rst |  5 ++-
 include/linux/xarray.h            | 52 +++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst
index 65c77a81b689..8a6e2087de77 100644
--- a/Documentation/core-api/xarray.rst
+++ b/Documentation/core-api/xarray.rst
@@ -167,6 +167,8 @@ Takes RCU read lock:
 
 Takes xa_lock internally:
  * :c:func:`xa_store`
+ * :c:func:`xa_store_bh`
+ * :c:func:`xa_store_irq`
  * :c:func:`xa_insert`
  * :c:func:`xa_erase`
  * :c:func:`xa_erase_bh`
@@ -247,7 +249,8 @@ Sharing the XArray with interrupt context is also possible, either
 using :c:func:`xa_lock_irqsave` in both the interrupt handler and process
 context, or :c:func:`xa_lock_irq` in process context and :c:func:`xa_lock`
 in the interrupt handler.  Some of the more common patterns have helper
-functions such as :c:func:`xa_erase_bh` and :c:func:`xa_erase_irq`.
+functions such as :c:func:`xa_store_bh`, :c:func:`xa_store_irq`,
+:c:func:`xa_erase_bh` and :c:func:`xa_erase_irq`.
 
 Sometimes you need to protect access to the XArray with a mutex because
 that lock sits above another mutex in the locking hierarchy.  That does
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index 4c839c17a99b..52d9732e4ec4 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -426,6 +426,58 @@ static inline int __xa_insert(struct xarray *xa, unsigned long index,
 	return -EEXIST;
 }
 
+/**
+ * xa_store_bh() - Store this entry in the XArray.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * This function is like calling xa_store() except it disables softirqs
+ * while holding the array lock.
+ *
+ * Context: Any context.  Takes and releases the xa_lock while
+ * disabling softirqs.
+ * Return: The entry which used to be at this index.
+ */
+static inline void *xa_store_bh(struct xarray *xa, unsigned long index,
+		void *entry, gfp_t gfp)
+{
+	void *curr;
+
+	xa_lock_bh(xa);
+	curr = __xa_store(xa, index, entry, gfp);
+	xa_unlock_bh(xa);
+
+	return curr;
+}
+
+/**
+ * xa_store_irq() - Erase this entry from the XArray.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * This function is like calling xa_store() except it disables interrupts
+ * while holding the array lock.
+ *
+ * Context: Process context.  Takes and releases the xa_lock while
+ * disabling interrupts.
+ * Return: The entry which used to be at this index.
+ */
+static inline void *xa_store_irq(struct xarray *xa, unsigned long index,
+		void *entry, gfp_t gfp)
+{
+	void *curr;
+
+	xa_lock_irq(xa);
+	curr = __xa_store(xa, index, entry, gfp);
+	xa_unlock_irq(xa);
+
+	return curr;
+}
+
 /**
  * xa_erase_bh() - Erase this entry from the XArray.
  * @xa: XArray.