dax: for truncate/hole-punch, do zeroing through the driver if possible

In the truncate or hole-punch path in dax, we clear out sub-page ranges.
If these sub-page ranges are sector aligned and sized, we can do the
zeroing through the driver instead so that error-clearing is handled
automatically.

For sub-sector ranges, we still have to rely on clear_pmem and have the
possibility of tripping over errors.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>

path: root/dev.h

#ifndef DEV_H
#define DEV_H

#include <sys/socket.h>
#include "built_in.h"

extern size_t device_mtu(const char *ifname);
extern int device_address(const char *ifname, int af, struct sockaddr_storage *ss);
extern int __device_ifindex(const char *ifname);
extern int device_hw_address(const char *ifname, uint8_t *addr, size_t len);
extern int device_ifindex(const char *ifname);
extern int device_type(const char *ifname);
extern short device_get_flags(const char *ifname);
extern void device_set_flags(const char *ifname, const short flags);
extern int device_up_and_running(const char *ifname);
extern uint32_t device_bitrate(const char *ifname);
extern short device_enter_promiscuous_mode(const char *ifname);
extern void device_leave_promiscuous_mode(const char *ifname, short oldflags);
extern const char *device_type2str(uint16_t type);
extern const char *device_addr2str(const unsigned char *addr, int alen, int type,
				   char *buf, int blen);
#endif /* DEV_H */