atmel-mci causes kernel panic when CONFIG_DEBUG_VM is set

Hello,

There is a bug with the atmel-mci driver when the debug feature 
CONFIG_DEBUG_VM is set.

Into the atmci_read_data_pio function we use flush_dcache_page (do we 
really need it?) which call the page_mapping function where we can find 
VM_BUG_ON(PageSlab(Page)). Then a kernel panic happens.

I don't understand the purpose of the VM_BUG_ON(PageSlab(Page)) (the 
page comes from a scatter list). How could I correct this problem?

Thanks for your help

Regards,

Ludovic