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Subject[PATCH 3/6] USB: gadget: f_hid: find f_hidg by IDR lookup on open
Date
As a step towards decoupling the cdev lifetime from f_hidg, lookup the
f_hidg structure by minor number from IDR when opening the device.

Signed-off-by: John Keeping <john@metanate.com>
---
drivers/usb/gadget/function/f_hid.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index 838256086bd2..4d20347fe908 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -441,8 +441,14 @@ static int f_hidg_release(struct inode *inode, struct file *fd)

static int f_hidg_open(struct inode *inode, struct file *fd)
{
- struct f_hidg *hidg =
- container_of(inode->i_cdev, struct f_hidg, cdev);
+ struct f_hidg *hidg;
+
+ mutex_lock(&hidg_idr_lock);
+ hidg = idr_find(&hidg_idr, iminor(inode));
+ mutex_unlock(&hidg_idr_lock);
+
+ if (!hidg)
+ return -ENODEV;

fd->private_data = hidg;

@@ -827,6 +833,10 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
if (status)
goto fail_free_descs;

+ mutex_lock(&hidg_idr_lock);
+ idr_replace(&hidg_idr, hidg, hidg->minor);
+ mutex_unlock(&hidg_idr_lock);
+
device = device_create(hidg_class, NULL, dev, NULL,
"%s%d", "hidg", hidg->minor);
if (IS_ERR(device)) {
--
2.23.0
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