mmc: block: Update ext_csd.cache_ctrl if it was written

The cache function can be turned ON and OFF by writing to the CACHE_CTRL
byte (EXT_CSD byte [33]).  However,  card->ext_csd.cache_ctrl is only
set on init if cache size > 0.

Fix that by explicitly setting ext_csd.cache_ctrl on ext-csd write.

Signed-off-by: Avri Altman <avri.altman@wdc.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210420134641.57343-3-avri.altman@wdc.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/block.c

@@ -572,6 +572,18 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct mmc_blk_data *md,
 		main_md->part_curr = value & EXT_CSD_PART_CONFIG_ACC_MASK;
 	}
 
+	/*
+	 * Make sure to update CACHE_CTRL in case it was changed. The cache
+	 * will get turned back on if the card is re-initialized, e.g.
+	 * suspend/resume or hw reset in recovery.
+	 */
+	if ((MMC_EXTRACT_INDEX_FROM_ARG(cmd.arg) == EXT_CSD_CACHE_CTRL) &&
+	    (cmd.opcode == MMC_SWITCH)) {
+		u8 value = MMC_EXTRACT_VALUE_FROM_ARG(cmd.arg) & 1;
+
+		card->ext_csd.cache_ctrl = value;
+	}
+
 	/*
 	 * According to the SD specs, some commands require a delay after
 	 * issuing the command.