[PATCH 4.9 36/53] idr: add ida_is_empty

[Greg Kroah-Hartman]

From: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>

[ Upstream commit 99c494077e2d4282a17120a772eecc00ec3004cc ]

Two of the USB Gadgets were poking around in the internals of struct ida
in order to determine if it is empty.  Add the appropriate abstraction.

Link: http://lkml.kernel.org/r/1480369871-5271-63-git-send-email-mawilcox@xxxxxxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Acked-by: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
Tested-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Felipe Balbi <balbi@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Nazarewicz <mina86@xxxxxxxxxx>
Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/usb/gadget/function/f_hid.c     | 6 +++---
 drivers/usb/gadget/function/f_printer.c | 6 +++---
 include/linux/idr.h                     | 5 +++++
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index 8e83649f77ce..42e5677d932d 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -932,7 +932,7 @@ static void hidg_free_inst(struct usb_function_instance *f)
 	mutex_lock(&hidg_ida_lock);
 
 	hidg_put_minor(opts->minor);
-	if (idr_is_empty(&hidg_ida.idr))
+	if (ida_is_empty(&hidg_ida))
 		ghid_cleanup();
 
 	mutex_unlock(&hidg_ida_lock);
@@ -958,7 +958,7 @@ static struct usb_function_instance *hidg_alloc_inst(void)
 
 	mutex_lock(&hidg_ida_lock);
 
-	if (idr_is_empty(&hidg_ida.idr)) {
+	if (ida_is_empty(&hidg_ida)) {
 		status = ghid_setup(NULL, HIDG_MINORS);
 		if (status)  {
 			ret = ERR_PTR(status);
@@ -971,7 +971,7 @@ static struct usb_function_instance *hidg_alloc_inst(void)
 	if (opts->minor < 0) {
 		ret = ERR_PTR(opts->minor);
 		kfree(opts);
-		if (idr_is_empty(&hidg_ida.idr))
+		if (ida_is_empty(&hidg_ida))
 			ghid_cleanup();
 		goto unlock;
 	}
diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c
index b962f24b500b..b3d036d06553 100644
--- a/drivers/usb/gadget/function/f_printer.c
+++ b/drivers/usb/gadget/function/f_printer.c
@@ -1276,7 +1276,7 @@ static void gprinter_free_inst(struct usb_function_instance *f)
 	mutex_lock(&printer_ida_lock);
 
 	gprinter_put_minor(opts->minor);
-	if (idr_is_empty(&printer_ida.idr))
+	if (ida_is_empty(&printer_ida))
 		gprinter_cleanup();
 
 	mutex_unlock(&printer_ida_lock);
@@ -1300,7 +1300,7 @@ static struct usb_function_instance *gprinter_alloc_inst(void)
 
 	mutex_lock(&printer_ida_lock);
 
-	if (idr_is_empty(&printer_ida.idr)) {
+	if (ida_is_empty(&printer_ida)) {
 		status = gprinter_setup(PRINTER_MINORS);
 		if (status) {
 			ret = ERR_PTR(status);
@@ -1313,7 +1313,7 @@ static struct usb_function_instance *gprinter_alloc_inst(void)
 	if (opts->minor < 0) {
 		ret = ERR_PTR(opts->minor);
 		kfree(opts);
-		if (idr_is_empty(&printer_ida.idr))
+		if (ida_is_empty(&printer_ida))
 			gprinter_cleanup();
 		goto unlock;
 	}
diff --git a/include/linux/idr.h b/include/linux/idr.h
index 083d61e92706..3639a28188c9 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -195,6 +195,11 @@ static inline int ida_get_new(struct ida *ida, int *p_id)
 	return ida_get_new_above(ida, 0, p_id);
 }
 
+static inline bool ida_is_empty(struct ida *ida)
+{
+	return idr_is_empty(&ida->idr);
+}
+
 void __init idr_init_cache(void);
 
 #endif /* __IDR_H__ */
-- 
2.30.1