On 6/15/2011 6:58 PM, Guennadi Liakhovetski wrote:
MMC host drivers have three main asynchronous event types, that they
report to the MMC core: request completions, SDIO interrupts and card
hotplug events. Avoid processing these calls during driver removal.
Signed-off-by: Guennadi Liakhovetski<g.liakhovetski@xxxxxx>
---
This is my attempt to answer my own question:
http://article.gmane.org/gmane.linux.kernel.mmc/8280
All these races are very unlikely, but can be triggered artificially by
inserting a delay in host drivers after mmc_remove_host().
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 68091dd..c11e47b 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -95,6 +95,9 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
struct mmc_command *cmd = mrq->cmd;
int err = cmd->error;
+ if (host->bus_dead)
+ return;
+
host->bus_dead is set when there are no interesting cards left on the
bus. It doesn't mean host driver being removed. Probably, you should use
host->removed instead.
if (err&& cmd->retries&& mmc_host_is_spi(host)) {
if (cmd->resp[0]& R1_SPI_ILLEGAL_COMMAND)
cmd->retries = 0;
@@ -1162,7 +1165,8 @@ void mmc_detect_change(struct mmc_host *host, unsigned long delay)
spin_unlock_irqrestore(&host->lock, flags);
#endif
- mmc_schedule_delayed_work(&host->detect, delay);
+ if (!host->bus_dead)
+ mmc_schedule_delayed_work(&host->detect, delay);
}
EXPORT_SYMBOL(mmc_detect_change);
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 1ee4424..1a1f2a4 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -311,6 +311,9 @@ extern void mmc_request_done(struct mmc_host *, struct mmc_request *);
static inline void mmc_signal_sdio_irq(struct mmc_host *host)
{
+ if (host->bus_dead)
+ return;
+
host->ops->enable_sdio_irq(host, 0);
wake_up_process(host->sdio_irq_thread);
}
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Thanks
Sujit
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