mmc: fix for old MMCs (below version 4)

The ext_csd is allocated only for MMC above version 4. The compare will
crash or fail for older MMCs.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 0ebcc45516621c542dabaa2ca632f8e593f3d156..2a58031c198421725a1be32f32bd024a4fefd24e 100644 (file)
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1657,6 +1657,9 @@ static int mmc_read_and_compare_ext_csd(struct mmc *mmc)
        const u8 *ext_csd = mmc->ext_csd;
        ALLOC_CACHE_ALIGN_BUFFER(u8, test_csd, MMC_MAX_BLOCK_LEN);
 
+       if (mmc->version < MMC_VERSION_4)
+               return 0;
+
        err = mmc_send_ext_csd(mmc, test_csd);
        if (err)
                return err;