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usb: typec: ucsi: Move unregister out of atomic section

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Commit '9329933699b3 ("soc: qcom: pmic_glink: Make client-lock
non-sleeping")' moved the pmic_glink client list under a spinlock, as it
is accessed by the rpmsg/glink callback, which in turn is invoked from
IRQ context.

This means that ucsi_unregister() is now called from atomic context,
which isn't feasible as it's expecting a sleepable context. An effort is
under way to get GLINK to invoke its callbacks in a sleepable context,
but until then lets schedule the unregistration.

A side effect of this is that ucsi_unregister() can now happen
after the remote processor, and thereby the communication link with it, is
gone. pmic_glink_send() is amended with a check to avoid the resulting NULL
pointer dereference.
This does however result in the user being informed about this error by
the following entry in the kernel log:

  ucsi_glink.pmic_glink_ucsi pmic_glink.ucsi.0: failed to send UCSI write request: -5

Fixes: 9329933699 ("soc: qcom: pmic_glink: Make client-lock non-sleeping")
Cc: stable@vger.kernel.org
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Amit Pundir <amit.pundir@linaro.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Link: https://lore.kernel.org/r/20240820-pmic-glink-v6-11-races-v3-2-eec53c750a04@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
This commit is contained in:
Bjorn Andersson 2024-08-20 13:29:31 -07:00 committed by Bjorn Andersson
parent 3568affcdd
commit 11bb2ffb67
2 changed files with 31 additions and 6 deletions
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10
drivers/soc/qcom/pmic_glink.c
View File

@ -112,8 +112,16 @@ EXPORT_SYMBOL_GPL(pmic_glink_client_register);
int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len)
{
struct pmic_glink *pg = client->pg;
int ret;
return rpmsg_send(pg->ept, data, len);
mutex_lock(&pg->state_lock);
if (!pg->ept)
ret = -ECONNRESET;
else
ret = rpmsg_send(pg->ept, data, len);
mutex_unlock(&pg->state_lock);
return ret;
}
EXPORT_SYMBOL_GPL(pmic_glink_send);

27
drivers/usb/typec/ucsi/ucsi_glink.c
View File

@ -68,6 +68,9 @@ struct pmic_glink_ucsi {
struct work_struct notify_work;
struct work_struct register_work;
spinlock_t state_lock;
bool ucsi_registered;
bool pd_running;
u8 read_buf[UCSI_BUF_SIZE];
};
@ -244,8 +247,20 @@ static void pmic_glink_ucsi_notify(struct work_struct *work)
static void pmic_glink_ucsi_register(struct work_struct *work)
{
struct pmic_glink_ucsi *ucsi = container_of(work, struct pmic_glink_ucsi, register_work);
unsigned long flags;
bool pd_running;
ucsi_register(ucsi->ucsi);
spin_lock_irqsave(&ucsi->state_lock, flags);
pd_running = ucsi->pd_running;
spin_unlock_irqrestore(&ucsi->state_lock, flags);
if (!ucsi->ucsi_registered && pd_running) {
ucsi_register(ucsi->ucsi);
ucsi->ucsi_registered = true;
} else if (ucsi->ucsi_registered && !pd_running) {
ucsi_unregister(ucsi->ucsi);
ucsi->ucsi_registered = false;
}
}
static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv)
@ -269,11 +284,12 @@ static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv)
static void pmic_glink_ucsi_pdr_notify(void *priv, int state)
{
struct pmic_glink_ucsi *ucsi = priv;
unsigned long flags;
if (state == SERVREG_SERVICE_STATE_UP)
schedule_work(&ucsi->register_work);
else if (state == SERVREG_SERVICE_STATE_DOWN)
ucsi_unregister(ucsi->ucsi);
spin_lock_irqsave(&ucsi->state_lock, flags);
ucsi->pd_running = (state == SERVREG_SERVICE_STATE_UP);
spin_unlock_irqrestore(&ucsi->state_lock, flags);
schedule_work(&ucsi->register_work);
}
static void pmic_glink_ucsi_destroy(void *data)
@ -320,6 +336,7 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev,
INIT_WORK(&ucsi->register_work, pmic_glink_ucsi_register);
init_completion(&ucsi->read_ack);
init_completion(&ucsi->write_ack);
spin_lock_init(&ucsi->state_lock);
mutex_init(&ucsi->lock);
ucsi->ucsi = ucsi_create(dev, &pmic_glink_ucsi_ops);