mmc: core: remove BUG_ONs from sdio

BUG_ONs doesn't help anything except for stop the system from
running. If it occurs, it implies we should deploy proper error
handling for that. So this patch is gonna discard these meaningless
BUG_ONs and deploy error handling if needed.

Signed-off-by: Shawn Lin <[e-mail]>
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/core/sdio.c

···
 	int ret;
 	struct sdio_func *func;
 
-	BUG_ON(fn > SDIO_MAX_FUNCS);
+	if (WARN_ON(fn > SDIO_MAX_FUNCS))
+		return -EINVAL;
 
 	func = sdio_alloc_func(card);
 	if (IS_ERR(func))
···
 	u32 rocr = 0;
 	u32 ocr_card = ocr;
 
-	BUG_ON(!host);
 	WARN_ON(!host->claimed);
 
 	/* to query card if 1.8V signalling is supported */
···
 {
 	int i;
 
-	BUG_ON(!host);
-	BUG_ON(!host->card);
-
 	for (i = 0;i < host->card->sdio_funcs;i++) {
 		if (host->card->sdio_func[i]) {
 			sdio_remove_func(host->card->sdio_func[i]);
···
 static void mmc_sdio_detect(struct mmc_host *host)
 {
 	int err;
-
-	BUG_ON(!host);
-	BUG_ON(!host->card);
 
 	/* Make sure card is powered before detecting it */
 	if (host->caps & MMC_CAP_POWER_OFF_CARD) {
···
 {
 	int err = 0;
 
-	BUG_ON(!host);
-	BUG_ON(!host->card);
-
 	/* Basic card reinitialization. */
 	mmc_claim_host(host);
 
···
 static int mmc_sdio_power_restore(struct mmc_host *host)
 {
 	int ret;
-
-	BUG_ON(!host);
-	BUG_ON(!host->card);
 
 	mmc_claim_host(host);
 
···
 	u32 ocr, rocr;
 	struct mmc_card *card;
 
-	BUG_ON(!host);
 	WARN_ON(!host->claimed);
 
 	err = mmc_send_io_op_cond(host, 0, &ocr);

drivers/mmc/core/sdio_cis.c

···
 	else
 		prev = &card->tuples;
 
-	BUG_ON(*prev);
+	if (*prev)
+		return -EINVAL;
 
 	do {
 		unsigned char tpl_code, tpl_link;

drivers/mmc/core/sdio_irq.c

···
 	struct mmc_host *host = card->host;
 
 	WARN_ON(!host->claimed);
-	BUG_ON(host->sdio_irqs < 1);
+
+	if (host->sdio_irqs < 1)
+		return -EINVAL;
 
 	if (!--host->sdio_irqs) {
 		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
···
 	int ret;
 	unsigned char reg;
 
-	BUG_ON(!func);
-	BUG_ON(!func->card);
+	if (!func)
+		return -EINVAL;
 
 	pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
 
···
 	int ret;
 	unsigned char reg;
 
-	BUG_ON(!func);
-	BUG_ON(!func->card);
+	if (!func)
+		return -EINVAL;
 
 	pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));