mmc: core: Detect card removal on I/O error

To prevent I/O as soon as possible at card removal, a new detect work is
re-scheduled without a delay to let a rescan remove the card device as
soon as possible.

Additionally, MMC_CAP2_DETECT_ON_ERR can now be used to handle "slowly"
removed cards that a scheduled detect work did not detect as removed.
To prevent further I/O requests for these lingering removed cards,
check if card has been removed and then schedule a detect work to
properly remove it.

Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/core/core.c

@@ -2121,18 +2121,36 @@ int _mmc_detect_card_removed(struct mmc_host *host)
 int mmc_detect_card_removed(struct mmc_host *host)
 {
 	struct mmc_card *card = host->card;
+	int ret;
 
 	WARN_ON(!host->claimed);
+
+	if (!card)
+		return 1;
+
+	ret = mmc_card_removed(card);
 	/*
 	 * The card will be considered unchanged unless we have been asked to
 	 * detect a change or host requires polling to provide card detection.
 	 */
-	if (card && !host->detect_change && !(host->caps & MMC_CAP_NEEDS_POLL))
-		return mmc_card_removed(card);
+	if (!host->detect_change && !(host->caps & MMC_CAP_NEEDS_POLL) &&
+	    !(host->caps2 & MMC_CAP2_DETECT_ON_ERR))
+		return ret;
 
 	host->detect_change = 0;
+	if (!ret) {
+		ret = _mmc_detect_card_removed(host);
+		if (ret && (host->caps2 & MMC_CAP2_DETECT_ON_ERR)) {
+			/*
+			 * Schedule a detect work as soon as possible to let a
+			 * rescan handle the card removal.
+			 */
+			cancel_delayed_work(&host->detect);
+			mmc_detect_change(host, 0);
+		}
+	}
 
-	return _mmc_detect_card_removed(host);
+	return ret;
 }
 EXPORT_SYMBOL(mmc_detect_card_removed);
 

include/linux/mmc/host.h

@@ -258,6 +258,7 @@ struct mmc_host {
 #define MMC_CAP2_HS200		(MMC_CAP2_HS200_1_8V_SDR | \
 				 MMC_CAP2_HS200_1_2V_SDR)
 #define MMC_CAP2_BROKEN_VOLTAGE	(1 << 7)	/* Use the broken voltage */
+#define MMC_CAP2_DETECT_ON_ERR	(1 << 8)	/* On I/O err check card removal */
 
 	mmc_pm_flag_t		pm_caps;	/* supported pm features */
 	unsigned int        power_notify_type;