6.10-stable review patch. If anyone has any objections, please let me know.
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From: Stephen Boyd swboyd@chromium.org
[ Upstream commit e43111f52b9ec5c2d700f89a1d61c8d10dc2d9e9 ]
Dan pointed out that Smatch is concerned about this code because it uses spin_lock_irqsave() and then calls wait_event_lock_irq() which enables irqs before going to sleep. The comment above the function says it should be called with interrupts enabled, but we simply hope that's true without really confirming that. Let's add a might_sleep() here to confirm that interrupts and preemption aren't disabled. Once we do that, we can change the lock to be non-saving, spin_lock_irq(), to clarify that we don't expect irqs to be disabled. If irqs are disabled by callers they're going to be enabled anyway in the wait_event_lock_irq() call which would be bad.
This should make Smatch happier and find bad callers faster with the might_sleep(). We can drop the WARN_ON() in the caller because we have the might_sleep() now, simplifying the code.
Reported-by: Dan Carpenter dan.carpenter@linaro.org Closes: https://lore.kernel.org/r/911181ed-c430-4592-ad26-4dc948834e08@moroto.mounta... Fixes: 2bc20f3c8487 ("soc: qcom: rpmh-rsc: Sleep waiting for tcs slots to be free") Cc: Douglas Anderson dianders@chromium.org Signed-off-by: Stephen Boyd swboyd@chromium.org Reviewed-by: Douglas Anderson dianders@chromium.org Link: https://lore.kernel.org/r/20240509184129.3924422-1-swboyd@chromium.org Signed-off-by: Bjorn Andersson andersson@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/soc/qcom/rpmh-rsc.c | 7 ++++--- drivers/soc/qcom/rpmh.c | 1 - 2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c index 561d8037b50a0..de86009ecd913 100644 --- a/drivers/soc/qcom/rpmh-rsc.c +++ b/drivers/soc/qcom/rpmh-rsc.c @@ -646,13 +646,14 @@ int rpmh_rsc_send_data(struct rsc_drv *drv, const struct tcs_request *msg) { struct tcs_group *tcs; int tcs_id; - unsigned long flags; + + might_sleep();
tcs = get_tcs_for_msg(drv, msg); if (IS_ERR(tcs)) return PTR_ERR(tcs);
- spin_lock_irqsave(&drv->lock, flags); + spin_lock_irq(&drv->lock);
/* Wait forever for a free tcs. It better be there eventually! */ wait_event_lock_irq(drv->tcs_wait, @@ -670,7 +671,7 @@ int rpmh_rsc_send_data(struct rsc_drv *drv, const struct tcs_request *msg) write_tcs_reg_sync(drv, drv->regs[RSC_DRV_CMD_ENABLE], tcs_id, 0); enable_tcs_irq(drv, tcs_id, true); } - spin_unlock_irqrestore(&drv->lock, flags); + spin_unlock_irq(&drv->lock);
/* * These two can be done after the lock is released because: diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c index 9f26d7f9b9dc4..8903ed956312d 100644 --- a/drivers/soc/qcom/rpmh.c +++ b/drivers/soc/qcom/rpmh.c @@ -183,7 +183,6 @@ static int __rpmh_write(const struct device *dev, enum rpmh_state state, }
if (state == RPMH_ACTIVE_ONLY_STATE) { - WARN_ON(irqs_disabled()); ret = rpmh_rsc_send_data(ctrlr_to_drv(ctrlr), &rpm_msg->msg); } else { /* Clean up our call by spoofing tx_done */