idr: add ida_is_empty

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@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Konstantin Khlebnikov <koct9i@gmail.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index 7abd70b..3151d2a 100644 (file)
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -905,7 +905,7 @@ 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);
@@ -931,7 +931,7 @@ 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);
@@ -944,7 +944,7 @@ 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 0de36cd..8054da9 100644 (file)
--- a/drivers/usb/gadget/function/f_printer.c
+++ b/drivers/usb/gadget/function/f_printer.c
@@ -1265,7 +1265,7 @@ 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);
@@ -1289,7 +1289,7 @@ 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);
@@ -1302,7 +1302,7 @@ 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 083d61e..3639a28 100644 (file)
--- 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__ */