|BDEV_DIRECT_ACCESS(9)||The Linux VFS||BDEV_DIRECT_ACCESS(9)|
bdev_direct_access - Get the address for directly-accessibly memory
long bdev_direct_access(struct block_device * bdev, struct blk_dax_ctl * dax);
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.
negative errno if an error occurs, otherwise the number of bytes accessible at this address.
|January 2017||Kernel Hackers Manual 4.8.|