BDEV_DIRECT_ACCESS(9)                     The Linux VFS                     BDEV_DIRECT_ACCESS(9)



NAME
       bdev_direct_access - Get the address for directly-accessibly memory

SYNOPSIS
       long bdev_direct_access(struct block_device * bdev, struct blk_dax_ctl * dax);

ARGUMENTS
       bdev
           The device containing the memory

       dax
           control and output parameters for ->direct_access

DESCRIPTION
       If a block device is made up of directly addressable memory, this function will tell the
       caller the PFN and the address of the memory. The address may be directly dereferenced
       within the kernel without the need to call ioremap, kmap or similar. The PFN is suitable
       for inserting into page tables.

RETURN
       negative errno if an error occurs, otherwise the number of bytes accessible at this
       address.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                     BDEV_DIRECT_ACCESS(9)