From: Matthew Wilcox <willy@infradead.org>
Date: Mon, 18 Feb 2019 20:20:22 +0000 (-0500)
Subject: ocxl: Convert minors_idr to XArray
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=35fda36a0cab840e033b3c15ca03cdf3e2ca840c;p=users%2Fwilly%2Fxarray.git

ocxl: Convert minors_idr to XArray

Signed-off-by: Matthew Wilcox <willy@infradead.org>
---

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index 2870c25da166f..1edbb7ddb3e1b 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -15,39 +15,34 @@
 
 static dev_t ocxl_dev;
 static struct class *ocxl_class;
-static struct mutex minors_idr_lock;
-static struct idr minors_idr;
+static DEFINE_XARRAY_ALLOC(ocxl_devs);
 
 static struct ocxl_file_info *find_file_info(dev_t devno)
 {
-	struct ocxl_file_info *info;
-
 	/*
 	 * We don't declare an RCU critical section here, as our AFU
 	 * is protected by a reference counter on the device. By the time the
-	 * info reference is removed from the idr, the ref count of
+	 * info reference is removed from the array, the ref count of
 	 * the device is already at 0, so no user API will access that AFU and
 	 * this function can't return it.
 	 */
-	info = idr_find(&minors_idr, MINOR(devno));
-	return info;
+	return xa_load(&ocxl_devs, MINOR(devno));
 }
 
 static int allocate_minor(struct ocxl_file_info *info)
 {
-	int minor;
+	int err, minor;
 
-	mutex_lock(&minors_idr_lock);
-	minor = idr_alloc(&minors_idr, info, 0, OCXL_NUM_MINORS, GFP_KERNEL);
-	mutex_unlock(&minors_idr_lock);
+	err = xa_alloc(&ocxl_devs, &minor, info,
+			XA_LIMIT(0, OCXL_NUM_MINORS - 1), GFP_KERNEL);
+	if (err < 0)
+		return err;
 	return minor;
 }
 
 static void free_minor(struct ocxl_file_info *info)
 {
-	mutex_lock(&minors_idr_lock);
-	idr_remove(&minors_idr, MINOR(info->dev.devt));
-	mutex_unlock(&minors_idr_lock);
+	xa_erase(&ocxl_devs, MINOR(info->dev.devt));
 }
 
 static int afu_open(struct inode *inode, struct file *file)
@@ -589,9 +584,6 @@ int ocxl_file_init(void)
 {
 	int rc;
 
-	mutex_init(&minors_idr_lock);
-	idr_init(&minors_idr);
-
 	rc = alloc_chrdev_region(&ocxl_dev, 0, OCXL_NUM_MINORS, "ocxl");
 	if (rc) {
 		pr_err("Unable to allocate ocxl major number: %d\n", rc);
@@ -613,5 +605,4 @@ void ocxl_file_exit(void)
 {
 	class_destroy(ocxl_class);
 	unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
-	idr_destroy(&minors_idr);
 }