| Message ID | 20211123001555.505546-2-elder@linaro.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 33a153100bb3459479bd95d3259c2915b53fefa8 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: ipa: prevent shutdown during setup | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for net |
| netdev/fixes_present | success | Fixes tag present in non-next series |
| netdev/subject_prefix | success | Link |
| netdev/cover_letter | success | Series has a cover letter |
| netdev/patch_count | success | Link |
| netdev/header_inline | success | No static functions without inline keyword in header files |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/cc_maintainers | success | CCed 4 of 4 maintainers |
| netdev/build_clang | success | Errors and warnings before: 0 this patch: 0 |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/verify_fixes | success | Fixes tag looks correct |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 49 lines checked |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
On Mon, Nov 22, 2021 at 06:15:54PM -0600, Alex Elder wrote: > We currently maintain a "disabled" Boolean flag to determine whether > the "ipa-setup-ready" SMP2P IRQ handler does anything. That flag > must be accessed under protection of a mutex. > > Instead, disable the SMP2P interrupt when requested, which prevents > the interrupt handler from ever being called. More importantly, it > synchronizes a thread disabling the interrupt with the completion of > the interrupt handler in case they run concurrently. > > Use the IPA setup_complete flag rather than the disabled flag in the > handler to determine whether to ignore any interrupts arriving after > the first. > > Rename the "disabled" flag to be "setup_disabled", to be specific > about its purpose. > > Fixes: 530f9216a953 ("soc: qcom: ipa: AP/modem communications") > Signed-off-by: Alex Elder <elder@linaro.org> I don't claim to know much about IPA, but this looks reasonable to me. Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
diff --git a/drivers/net/ipa/ipa_smp2p.c b/drivers/net/ipa/ipa_smp2p.c index df7639c39d716..24bc112a072c6 100644 --- a/drivers/net/ipa/ipa_smp2p.c +++ b/drivers/net/ipa/ipa_smp2p.c @@ -53,7 +53,7 @@ * @setup_ready_irq: IPA interrupt triggered by modem to signal GSI ready * @power_on: Whether IPA power is on * @notified: Whether modem has been notified of power state - * @disabled: Whether setup ready interrupt handling is disabled + * @setup_disabled: Whether setup ready interrupt handler is disabled * @mutex: Mutex protecting ready-interrupt/shutdown interlock * @panic_notifier: Panic notifier structure */ @@ -67,7 +67,7 @@ struct ipa_smp2p { u32 setup_ready_irq; bool power_on; bool notified; - bool disabled; + bool setup_disabled; struct mutex mutex; struct notifier_block panic_notifier; }; @@ -155,11 +155,9 @@ static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id) struct device *dev; int ret; - mutex_lock(&smp2p->mutex); - - if (smp2p->disabled) - goto out_mutex_unlock; - smp2p->disabled = true; /* If any others arrive, ignore them */ + /* Ignore any (spurious) interrupts received after the first */ + if (smp2p->ipa->setup_complete) + return IRQ_HANDLED; /* Power needs to be active for setup */ dev = &smp2p->ipa->pdev->dev; @@ -176,8 +174,6 @@ static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id) out_power_put: pm_runtime_mark_last_busy(dev); (void)pm_runtime_put_autosuspend(dev); -out_mutex_unlock: - mutex_unlock(&smp2p->mutex); return IRQ_HANDLED; } @@ -322,7 +318,10 @@ void ipa_smp2p_disable(struct ipa *ipa) mutex_lock(&smp2p->mutex); - smp2p->disabled = true; + if (!smp2p->setup_disabled) { + disable_irq(smp2p->setup_ready_irq); + smp2p->setup_disabled = true; + } mutex_unlock(&smp2p->mutex); }
We currently maintain a "disabled" Boolean flag to determine whether the "ipa-setup-ready" SMP2P IRQ handler does anything. That flag must be accessed under protection of a mutex. Instead, disable the SMP2P interrupt when requested, which prevents the interrupt handler from ever being called. More importantly, it synchronizes a thread disabling the interrupt with the completion of the interrupt handler in case they run concurrently. Use the IPA setup_complete flag rather than the disabled flag in the handler to determine whether to ignore any interrupts arriving after the first. Rename the "disabled" flag to be "setup_disabled", to be specific about its purpose. Fixes: 530f9216a953 ("soc: qcom: ipa: AP/modem communications") Signed-off-by: Alex Elder <elder@linaro.org> --- drivers/net/ipa/ipa_smp2p.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-)