On 11/05/17 15:39, Ulf Hansson wrote: > In a step to simplify the use of the lock, mmc_claim|release_host(), let's > change the SDIO IRQ thread to move away from using the abort-able claim > host method. > > In the SDIO IRQ thread case, we can instead check the numbers of SDIO IRQs > that are currently claimed via host->sdio_irqs, as this field is protected > from updates unless the host is claimed. When host->sdio_irqs has become > zero, it means the SDIO func driver(s) has released the SDIO IRQ, then we > can bail out and stop running the SDIO IRQ thread.
Does that work? It looks a like kthread_stop() will wait on the thread, which is waiting to claim the host, which is claimed by the caller of sdio_card_irq_put() which called kthread_stop() i.e. deadlock. > > Signed-off-by: Ulf Hansson <[email protected]> > --- > drivers/mmc/core/sdio_irq.c | 10 ++++++---- > include/linux/mmc/host.h | 1 - > 2 files changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c > index 6d4b720..95f7a09 100644 > --- a/drivers/mmc/core/sdio_irq.c > +++ b/drivers/mmc/core/sdio_irq.c > @@ -137,9 +137,13 @@ static int sdio_irq_thread(void *_host) > * holding of the host lock does not cover too much work > * that doesn't require that lock to be held. > */ > - ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort); > - if (ret) > + mmc_claim_host(host); > + if (!host->sdio_irqs) { > + ret = 1; > + mmc_release_host(host); > break; > + } > + > ret = process_sdio_pending_irqs(host); > host->sdio_irq_pending = false; > mmc_release_host(host); > @@ -195,7 +199,6 @@ static int sdio_card_irq_get(struct mmc_card *card) > > if (!host->sdio_irqs++) { > if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) { > - atomic_set(&host->sdio_irq_thread_abort, 0); > host->sdio_irq_thread = > kthread_run(sdio_irq_thread, host, > "ksdioirqd/%s", mmc_hostname(host)); > @@ -223,7 +226,6 @@ static int sdio_card_irq_put(struct mmc_card *card) > > if (!--host->sdio_irqs) { > if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) { > - atomic_set(&host->sdio_irq_thread_abort, 1); > kthread_stop(host->sdio_irq_thread); > } else if (host->caps & MMC_CAP_SDIO_IRQ) { > host->ops->enable_sdio_irq(host, 0); > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h > index 21385ac..8a4131f 100644 > --- a/include/linux/mmc/host.h > +++ b/include/linux/mmc/host.h > @@ -359,7 +359,6 @@ struct mmc_host { > unsigned int sdio_irqs; > struct task_struct *sdio_irq_thread; > bool sdio_irq_pending; > - atomic_t sdio_irq_thread_abort; > > mmc_pm_flag_t pm_flags; /* requested pm features */ > >
