From: Guenter Roeck <linux@roeck-us.net>
To: Hans de Goede <hdegoede@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: linux-usb@vger.kernel.org
Subject: Re: [PATCH v2 2/6] usb: typec: tcpm: Add tcpm_queue_vdm_unlocked() helper
Date: Sat, 25 Jul 2020 07:37:50 -0700 [thread overview]
Message-ID: <1e91918e-accc-532a-d44a-681a9374f92b@roeck-us.net> (raw)
In-Reply-To: <20200724174702.61754-2-hdegoede@redhat.com>
On 7/24/20 10:46 AM, Hans de Goede wrote:
> Various callers (all the typec_altmode_ops) take the port-lock just for
> the tcpm_queue_vdm() call.
>
> Add a new tcpm_queue_vdm_unlocked() helper which takes the lock, so that
> its callers don't have to do this themselves.
>
> This is a preparation patch for fixing an AB BA lock inversion between
> the tcpm code and some altmode drivers.
>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Changes in v2:
> - Name the new helper tcpm_queue_vdm_unlocked() instead of renaming the
> original function to this
> ---
> drivers/usb/typec/tcpm/tcpm.c | 25 +++++++++++++------------
> 1 file changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index fc6455a29c74..862c474b3ebd 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -961,6 +961,8 @@ static void tcpm_queue_message(struct tcpm_port *port,
> static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header,
> const u32 *data, int cnt)
> {
> + WARN_ON(!mutex_is_locked(&port->lock));
> +
> port->vdo_count = cnt + 1;
> port->vdo_data[0] = header;
> memcpy(&port->vdo_data[1], data, sizeof(u32) * cnt);
> @@ -971,6 +973,14 @@ static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header,
> mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> }
>
> +static void tcpm_queue_vdm_unlocked(struct tcpm_port *port, const u32 header,
> + const u32 *data, int cnt)
> +{
> + mutex_lock(&port->lock);
> + tcpm_queue_vdm(port, header, data, cnt);
> + mutex_unlock(&port->lock);
> +}
> +
> static void svdm_consume_identity(struct tcpm_port *port, const __le32 *payload,
> int cnt)
> {
> @@ -1506,13 +1516,10 @@ static int tcpm_altmode_enter(struct typec_altmode *altmode, u32 *vdo)
> struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> u32 header;
>
> - mutex_lock(&port->lock);
> header = VDO(altmode->svid, vdo ? 2 : 1, CMD_ENTER_MODE);
> header |= VDO_OPOS(altmode->mode);
>
> - tcpm_queue_vdm(port, header, vdo, vdo ? 1 : 0);
> - mutex_unlock(&port->lock);
> -
> + tcpm_queue_vdm_unlocked(port, header, vdo, vdo ? 1 : 0);
> return 0;
> }
>
> @@ -1521,13 +1528,10 @@ static int tcpm_altmode_exit(struct typec_altmode *altmode)
> struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> u32 header;
>
> - mutex_lock(&port->lock);
> header = VDO(altmode->svid, 1, CMD_EXIT_MODE);
> header |= VDO_OPOS(altmode->mode);
>
> - tcpm_queue_vdm(port, header, NULL, 0);
> - mutex_unlock(&port->lock);
> -
> + tcpm_queue_vdm_unlocked(port, header, NULL, 0);
> return 0;
> }
>
> @@ -1536,10 +1540,7 @@ static int tcpm_altmode_vdm(struct typec_altmode *altmode,
> {
> struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
>
> - mutex_lock(&port->lock);
> - tcpm_queue_vdm(port, header, data, count - 1);
> - mutex_unlock(&port->lock);
> -
> + tcpm_queue_vdm_unlocked(port, header, data, count - 1);
> return 0;
> }
>
>
next prev parent reply other threads:[~2020-07-25 14:37 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-24 17:46 [PATCH v2 1/6] usb: typec: tcpm: Move mod_delayed_work(&port->vdm_state_machine) call into tcpm_queue_vdm() Hans de Goede
2020-07-24 17:46 ` [PATCH v2 2/6] usb: typec: tcpm: Add tcpm_queue_vdm_unlocked() helper Hans de Goede
2020-07-25 14:37 ` Guenter Roeck [this message]
2020-07-28 12:44 ` Heikki Krogerus
2020-07-24 17:46 ` [PATCH v2 3/6] usb: typec: tcpm: Refactor tcpm_handle_vdm_request payload handling Hans de Goede
2020-07-28 12:59 ` Heikki Krogerus
2020-07-24 17:47 ` [PATCH v2 4/6] usb: typec: tcpm: Refactor tcpm_handle_vdm_request Hans de Goede
2020-07-25 14:45 ` Guenter Roeck
2020-07-26 10:58 ` Hans de Goede
2020-07-26 13:22 ` Guenter Roeck
2020-07-28 13:06 ` Heikki Krogerus
2020-07-24 17:47 ` [PATCH v2 5/6] usb: typec: tcpm: Fix AB BA lock inversion between tcpm code and the alt-mode drivers Hans de Goede
2020-07-25 14:46 ` Guenter Roeck
2020-07-28 13:08 ` Heikki Krogerus
2020-07-24 17:47 ` [PATCH v2 6/6] usb: typec: tcpm: Add WARN_ON ensure we are not trying to send 2 VDM packets at the same time Hans de Goede
2020-07-24 17:57 ` Sergei Shtylyov
2020-07-24 19:09 ` Hans de Goede
2020-07-25 14:53 ` Guenter Roeck
2020-07-28 13:10 ` Heikki Krogerus
2020-07-28 12:43 ` [PATCH v2 1/6] usb: typec: tcpm: Move mod_delayed_work(&port->vdm_state_machine) call into tcpm_queue_vdm() Heikki Krogerus
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