linux-kernel - [PATCH 2/6] USB: gadget: f_hid: switch to IDR for tracking minors

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Message-Id: <20191024164538.3161474-3-john@metanate.com>
Date:   Thu, 24 Oct 2019 17:45:34 +0100
From:   John Keeping <john@...anate.com>
To:     linux-usb@...r.kernel.org
Cc:     Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, John Keeping <john@...anate.com>
Subject: [PATCH 2/6] USB: gadget: f_hid: switch to IDR for tracking minors

In the following commits, we are going to move the cdev allocation up to
the module initialisation, and will look up the associated f_hidg
structure from the open operation.

Start preparing for this by switching from IDA to IDR.

Signed-off-by: John Keeping <john@...anate.com>
---
 drivers/usb/gadget/function/f_hid.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index e9e45f9eae80..838256086bd2 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -24,8 +24,8 @@
 
 static int major, minors;
 static struct class *hidg_class;
-static DEFINE_IDA(hidg_ida);
-static DEFINE_MUTEX(hidg_ida_lock); /* protects access to hidg_ida */
+static DEFINE_IDR(hidg_idr);
+static DEFINE_MUTEX(hidg_idr_lock); /* protects access to hidg_idr */
 
 /*-------------------------------------------------------------------------*/
 /*                            HID gadget struct                            */
@@ -851,9 +851,9 @@ static inline int hidg_get_minor(void)
 {
 	int ret;
 
-	ret = ida_simple_get(&hidg_ida, 0, 0, GFP_KERNEL);
+	ret = idr_alloc(&hidg_idr, NULL, 0, 0, GFP_KERNEL);
 	if (ret >= HIDG_MINORS) {
-		ida_simple_remove(&hidg_ida, ret);
+		idr_remove(&hidg_idr, ret);
 		ret = -ENODEV;
 	}
 
@@ -996,7 +996,7 @@ static const struct config_item_type hid_func_type = {
 
 static inline void hidg_put_minor(int minor)
 {
-	ida_simple_remove(&hidg_ida, minor);
+	idr_remove(&hidg_idr, minor);
 }
 
 static void hidg_free_inst(struct usb_function_instance *f)
@@ -1005,9 +1005,9 @@ static void hidg_free_inst(struct usb_function_instance *f)
 
 	opts = container_of(f, struct f_hid_opts, func_inst);
 
-	mutex_lock(&hidg_ida_lock);
+	mutex_lock(&hidg_idr_lock);
 	hidg_put_minor(opts->minor);
-	mutex_unlock(&hidg_ida_lock);
+	mutex_unlock(&hidg_idr_lock);
 
 	if (opts->report_desc_alloc)
 		kfree(opts->report_desc);
@@ -1027,7 +1027,7 @@ static struct usb_function_instance *hidg_alloc_inst(void)
 	opts->func_inst.free_func_inst = hidg_free_inst;
 	ret = &opts->func_inst;
 
-	mutex_lock(&hidg_ida_lock);
+	mutex_lock(&hidg_idr_lock);
 
 	opts->minor = hidg_get_minor();
 	if (opts->minor < 0) {
@@ -1038,7 +1038,7 @@ static struct usb_function_instance *hidg_alloc_inst(void)
 	config_group_init_type_name(&opts->func_inst.group, "", &hid_func_type);
 
 unlock:
-	mutex_unlock(&hidg_ida_lock);
+	mutex_unlock(&hidg_idr_lock);
 	return ret;
 }
 
-- 
2.23.0