[PATCH] HID: hidraw: enforce minors_lock locking via lockdep

[PATCH] HID: hidraw: enforce minors_lock locking via lockdep

[Jiri Kosina]

From: Jiri Kosina <jkosina@suse.cz>

lockdep is much more powerful enforcing the locking rules than code comments,
so let's switch to it.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
 drivers/hid/hidraw.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 4a44e48e08b2..cf2af069204f 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -107,8 +107,6 @@ static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count,
 
 /*
  * The first byte of the report buffer is expected to be a report number.
- *
- * This function is to be called with the minors_lock mutex held.
  */
 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
 {
@@ -117,6 +115,8 @@ static ssize_t hidraw_send_report(struct file *file, const char __user *buffer,
 	__u8 *buf;
 	int ret = 0;
 
+	lockdep_assert_held(&minors_lock);
+
 	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 		ret = -ENODEV;
 		goto out;
@@ -192,6 +192,8 @@ static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t
 	int ret = 0, len;
 	unsigned char report_number;
 
+	lockdep_assert_held(&minors_lock);
+
 	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 		ret = -ENODEV;
 		goto out;
-- 
Jiri Kosina
SUSE Labs

Re: [PATCH] HID: hidraw: enforce minors_lock locking via lockdep

[Benjamin Tissoires]

On Thu, Nov 8, 2018 at 10:38 PM Jiri Kosina <jikos@kernel.org> wrote:
>
> From: Jiri Kosina <jkosina@suse.cz>
>
> lockdep is much more powerful enforcing the locking rules than code comments,
> so let's switch to it.
>
> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
> ---

Looks good to me.

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Cheers,
Benjamin

>  drivers/hid/hidraw.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
> index 4a44e48e08b2..cf2af069204f 100644
> --- a/drivers/hid/hidraw.c
> +++ b/drivers/hid/hidraw.c
> @@ -107,8 +107,6 @@ static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count,
>
>  /*
>   * The first byte of the report buffer is expected to be a report number.
> - *
> - * This function is to be called with the minors_lock mutex held.
>   */
>  static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
>  {
> @@ -117,6 +115,8 @@ static ssize_t hidraw_send_report(struct file *file, const char __user *buffer,
>         __u8 *buf;
>         int ret = 0;
>
> +       lockdep_assert_held(&minors_lock);
> +
>         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
>                 ret = -ENODEV;
>                 goto out;
> @@ -192,6 +192,8 @@ static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t
>         int ret = 0, len;
>         unsigned char report_number;
>
> +       lockdep_assert_held(&minors_lock);
> +
>         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
>                 ret = -ENODEV;
>                 goto out;
> --
> Jiri Kosina
> SUSE Labs
>

Re: [PATCH] HID: hidraw: enforce minors_lock locking via lockdep

[Jiri Kosina]

On Fri, 9 Nov 2018, Benjamin Tissoires wrote:

> On Thu, Nov 8, 2018 at 10:38 PM Jiri Kosina <jikos@kernel.org> wrote:
> >
> > From: Jiri Kosina <jkosina@suse.cz>
> >
> > lockdep is much more powerful enforcing the locking rules than code comments,
> > so let's switch to it.
> >
> > Signed-off-by: Jiri Kosina <jkosina@suse.cz>
> > ---
> 
> Looks good to me.
> 
> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

I actually missed the comment removal for hidraw_get_report(). I've 
ammeded the patch and comitted, keeping your tag, please shout if you 
disagree :)

Thanks.

-- 
Jiri Kosina
SUSE Labs