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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

struct block_device * bdev

The device containing the memory

struct blk_dax_ctl * 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

July 2017 Kernel Hackers Manual 4.11