mmc: check find_mmc_device return value

find_mmc_device returns NULL if an invalid device number is specified.
Check for this to avoid dereferencing NULL pointers.

Signed-off-by: Rabin Vincent <rabin@rab.in>

diff --git a/common/cmd_mmc.c b/common/cmd_mmc.c
index bd55ff1..039fe59 100644 (file)
--- a/common/cmd_mmc.c
+++ b/common/cmd_mmc.c
@@ -149,6 +149,9 @@ int do_mmcops(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
                        int dev = simple_strtoul(argv[2], NULL, 10);
                        struct mmc *mmc = find_mmc_device(dev);
 
+                       if (!mmc)
+                               return 1;
+
                        mmc_init(mmc);
 
                        return 0;
@@ -175,6 +178,9 @@ int do_mmcops(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
                        u32 blk = simple_strtoul(argv[4], NULL, 16);
                        struct mmc *mmc = find_mmc_device(dev);
 
+                       if (!mmc)
+                               return 1;
+
                        printf("\nMMC read: dev # %d, block # %d, count %d ... ",
                                dev, blk, cnt);
 
@@ -197,6 +203,9 @@ int do_mmcops(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 
                        int blk = simple_strtoul(argv[4], NULL, 16);
 
+                       if (!mmc)
+                               return 1;
+
                        printf("\nMMC write: dev # %d, block # %d, count %d ... ",
                                dev, blk, cnt);
 

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 7791c38..70b4130 100644 (file)
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -846,7 +846,7 @@ block_dev_desc_t *mmc_get_dev(int dev)
 {
        struct mmc *mmc = find_mmc_device(dev);
 
-       return &mmc->block_dev;
+       return mmc ? &mmc->block_dev : NULL;
 }
 
 int mmc_init(struct mmc *mmc)