| From 2bc48abaadf785fe514254db6425f350565f6848 Mon Sep 17 00:00:00 2001 |
| From: Dmitry Torokhov <dmitry.torokhov@gmail.com> |
| Date: Tue, 17 Dec 2019 14:50:21 -0800 |
| Subject: [PATCH] HID: hiddev: fix mess in hiddev_open() |
| |
| commit 18a1b06e5b91d47dc86c0a66a762646ea7c5d141 upstream. |
| |
| The open method of hiddev handler fails to bring the device out of |
| autosuspend state as was promised in 0361a28d3f9a, as it actually has 2 |
| blocks that try to start the transport (call hid_hw_open()) with both |
| being guarded by the "open" counter, so the 2nd block is never executed as |
| the first block increments the counter so it is never at 0 when we check |
| it for the second block. |
| |
| Additionally hiddev_open() was leaving counter incremented on errors, |
| causing the device to never be reopened properly if there was ever an |
| error. |
| |
| Let's fix all of this by factoring out code that creates client structure |
| and powers up the device into a separate function that is being called |
| from usbhid_open() with the "existancelock" being held. |
| |
| Fixes: 0361a28d3f9a ("HID: autosuspend support for USB HID") |
| Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> |
| Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c |
| index 4e11cc6fc34b..4aac11d8535a 100644 |
| --- a/drivers/hid/usbhid/hiddev.c |
| +++ b/drivers/hid/usbhid/hiddev.c |
| @@ -241,12 +241,51 @@ static int hiddev_release(struct inode * inode, struct file * file) |
| return 0; |
| } |
| |
| +static int __hiddev_open(struct hiddev *hiddev, struct file *file) |
| +{ |
| + struct hiddev_list *list; |
| + int error; |
| + |
| + lockdep_assert_held(&hiddev->existancelock); |
| + |
| + list = vzalloc(sizeof(*list)); |
| + if (!list) |
| + return -ENOMEM; |
| + |
| + mutex_init(&list->thread_lock); |
| + list->hiddev = hiddev; |
| + |
| + if (!hiddev->open++) { |
| + error = hid_hw_power(hiddev->hid, PM_HINT_FULLON); |
| + if (error < 0) |
| + goto err_drop_count; |
| + |
| + error = hid_hw_open(hiddev->hid); |
| + if (error < 0) |
| + goto err_normal_power; |
| + } |
| + |
| + spin_lock_irq(&hiddev->list_lock); |
| + list_add_tail(&list->node, &hiddev->list); |
| + spin_unlock_irq(&hiddev->list_lock); |
| + |
| + file->private_data = list; |
| + |
| + return 0; |
| + |
| +err_normal_power: |
| + hid_hw_power(hiddev->hid, PM_HINT_NORMAL); |
| +err_drop_count: |
| + hiddev->open--; |
| + vfree(list); |
| + return error; |
| +} |
| + |
| /* |
| * open file op |
| */ |
| static int hiddev_open(struct inode *inode, struct file *file) |
| { |
| - struct hiddev_list *list; |
| struct usb_interface *intf; |
| struct hid_device *hid; |
| struct hiddev *hiddev; |
| @@ -255,66 +294,14 @@ static int hiddev_open(struct inode *inode, struct file *file) |
| intf = usbhid_find_interface(iminor(inode)); |
| if (!intf) |
| return -ENODEV; |
| + |
| hid = usb_get_intfdata(intf); |
| hiddev = hid->hiddev; |
| |
| - if (!(list = vzalloc(sizeof(struct hiddev_list)))) |
| - return -ENOMEM; |
| - mutex_init(&list->thread_lock); |
| - list->hiddev = hiddev; |
| - file->private_data = list; |
| - |
| - /* |
| - * no need for locking because the USB major number |
| - * is shared which usbcore guards against disconnect |
| - */ |
| - if (list->hiddev->exist) { |
| - if (!list->hiddev->open++) { |
| - res = hid_hw_open(hiddev->hid); |
| - if (res < 0) |
| - goto bail; |
| - } |
| - } else { |
| - res = -ENODEV; |
| - goto bail; |
| - } |
| - |
| - spin_lock_irq(&list->hiddev->list_lock); |
| - list_add_tail(&list->node, &hiddev->list); |
| - spin_unlock_irq(&list->hiddev->list_lock); |
| - |
| mutex_lock(&hiddev->existancelock); |
| - /* |
| - * recheck exist with existance lock held to |
| - * avoid opening a disconnected device |
| - */ |
| - if (!list->hiddev->exist) { |
| - res = -ENODEV; |
| - goto bail_unlock; |
| - } |
| - if (!list->hiddev->open++) |
| - if (list->hiddev->exist) { |
| - struct hid_device *hid = hiddev->hid; |
| - res = hid_hw_power(hid, PM_HINT_FULLON); |
| - if (res < 0) |
| - goto bail_unlock; |
| - res = hid_hw_open(hid); |
| - if (res < 0) |
| - goto bail_normal_power; |
| - } |
| - mutex_unlock(&hiddev->existancelock); |
| - return 0; |
| -bail_normal_power: |
| - hid_hw_power(hid, PM_HINT_NORMAL); |
| -bail_unlock: |
| + res = hiddev->exist ? __hiddev_open(hiddev, file) : -ENODEV; |
| mutex_unlock(&hiddev->existancelock); |
| |
| - spin_lock_irq(&list->hiddev->list_lock); |
| - list_del(&list->node); |
| - spin_unlock_irq(&list->hiddev->list_lock); |
| -bail: |
| - file->private_data = NULL; |
| - vfree(list); |
| return res; |
| } |
| |
| -- |
| 2.7.4 |
| |