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.liakhovet...@gmx.de>
---

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;
+
        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);
 }
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to