linux/drivers/md/dm-target.c
Linus Torvalds f0c98ebc57 libnvdimm for 4.8
1/ Replace pcommit with ADR / directed-flushing:
    The pcommit instruction, which has not shipped on any product, is
    deprecated. Instead, the requirement is that platforms implement either
    ADR, or provide one or more flush addresses per nvdimm. ADR
    (Asynchronous DRAM Refresh) flushes data in posted write buffers to the
    memory controller on a power-fail event. Flush addresses are defined in
    ACPI 6.x as an NVDIMM Firmware Interface Table (NFIT) sub-structure:
    "Flush Hint Address Structure". A flush hint is an mmio address that
    when written and fenced assures that all previous posted writes
    targeting a given dimm have been flushed to media.
 
 2/ On-demand ARS (address range scrub):
    Linux uses the results of the ACPI ARS commands to track bad blocks
    in pmem devices.  When latent errors are detected we re-scrub the media
    to refresh the bad block list, userspace can also request a re-scrub at
    any time.
 
 3/ Support for the Microsoft DSM (device specific method) command format.
 
 4/ Support for EDK2/OVMF virtual disk device memory ranges.
 
 5/ Various fixes and cleanups across the subsystem.
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Merge tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:

 - Replace pcommit with ADR / directed-flushing.

   The pcommit instruction, which has not shipped on any product, is
   deprecated.  Instead, the requirement is that platforms implement
   either ADR, or provide one or more flush addresses per nvdimm.

   ADR (Asynchronous DRAM Refresh) flushes data in posted write buffers
   to the memory controller on a power-fail event.

   Flush addresses are defined in ACPI 6.x as an NVDIMM Firmware
   Interface Table (NFIT) sub-structure: "Flush Hint Address Structure".
   A flush hint is an mmio address that when written and fenced assures
   that all previous posted writes targeting a given dimm have been
   flushed to media.

 - On-demand ARS (address range scrub).

   Linux uses the results of the ACPI ARS commands to track bad blocks
   in pmem devices.  When latent errors are detected we re-scrub the
   media to refresh the bad block list, userspace can also request a
   re-scrub at any time.

 - Support for the Microsoft DSM (device specific method) command
   format.

 - Support for EDK2/OVMF virtual disk device memory ranges.

 - Various fixes and cleanups across the subsystem.

* tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (41 commits)
  libnvdimm-btt: Delete an unnecessary check before the function call "__nd_device_register"
  nfit: do an ARS scrub on hitting a latent media error
  nfit: move to nfit/ sub-directory
  nfit, libnvdimm: allow an ARS scrub to be triggered on demand
  libnvdimm: register nvdimm_bus devices with an nd_bus driver
  pmem: clarify a debug print in pmem_clear_poison
  x86/insn: remove pcommit
  Revert "KVM: x86: add pcommit support"
  nfit, tools/testing/nvdimm/: unify shutdown paths
  libnvdimm: move ->module to struct nvdimm_bus_descriptor
  nfit: cleanup acpi_nfit_init calling convention
  nfit: fix _FIT evaluation memory leak + use after free
  tools/testing/nvdimm: add manufacturing_{date|location} dimm properties
  tools/testing/nvdimm: add virtual ramdisk range
  acpi, nfit: treat virtual ramdisk SPA as pmem region
  pmem: kill __pmem address space
  pmem: kill wmb_pmem()
  libnvdimm, pmem: use nvdimm_flush() for namespace I/O writes
  fs/dax: remove wmb_pmem()
  libnvdimm, pmem: flush posted-write queues on shutdown
  ...
2016-07-28 17:38:16 -07:00

182 lines
3.2 KiB
C

/*
* Copyright (C) 2001 Sistina Software (UK) Limited
*
* This file is released under the GPL.
*/
#include "dm-core.h"
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/bio.h>
#define DM_MSG_PREFIX "target"
static LIST_HEAD(_targets);
static DECLARE_RWSEM(_lock);
#define DM_MOD_NAME_SIZE 32
static inline struct target_type *__find_target_type(const char *name)
{
struct target_type *tt;
list_for_each_entry(tt, &_targets, list)
if (!strcmp(name, tt->name))
return tt;
return NULL;
}
static struct target_type *get_target_type(const char *name)
{
struct target_type *tt;
down_read(&_lock);
tt = __find_target_type(name);
if (tt && !try_module_get(tt->module))
tt = NULL;
up_read(&_lock);
return tt;
}
static void load_module(const char *name)
{
request_module("dm-%s", name);
}
struct target_type *dm_get_target_type(const char *name)
{
struct target_type *tt = get_target_type(name);
if (!tt) {
load_module(name);
tt = get_target_type(name);
}
return tt;
}
void dm_put_target_type(struct target_type *tt)
{
down_read(&_lock);
module_put(tt->module);
up_read(&_lock);
}
int dm_target_iterate(void (*iter_func)(struct target_type *tt,
void *param), void *param)
{
struct target_type *tt;
down_read(&_lock);
list_for_each_entry(tt, &_targets, list)
iter_func(tt, param);
up_read(&_lock);
return 0;
}
int dm_register_target(struct target_type *tt)
{
int rv = 0;
down_write(&_lock);
if (__find_target_type(tt->name))
rv = -EEXIST;
else
list_add(&tt->list, &_targets);
up_write(&_lock);
return rv;
}
void dm_unregister_target(struct target_type *tt)
{
down_write(&_lock);
if (!__find_target_type(tt->name)) {
DMCRIT("Unregistering unrecognised target: %s", tt->name);
BUG();
}
list_del(&tt->list);
up_write(&_lock);
}
/*
* io-err: always fails an io, useful for bringing
* up LVs that have holes in them.
*/
static int io_err_ctr(struct dm_target *tt, unsigned int argc, char **args)
{
/*
* Return error for discards instead of -EOPNOTSUPP
*/
tt->num_discard_bios = 1;
return 0;
}
static void io_err_dtr(struct dm_target *tt)
{
/* empty */
}
static int io_err_map(struct dm_target *tt, struct bio *bio)
{
return -EIO;
}
static int io_err_map_rq(struct dm_target *ti, struct request *clone,
union map_info *map_context)
{
return -EIO;
}
static int io_err_clone_and_map_rq(struct dm_target *ti, struct request *rq,
union map_info *map_context,
struct request **clone)
{
return -EIO;
}
static void io_err_release_clone_rq(struct request *clone)
{
}
static long io_err_direct_access(struct dm_target *ti, sector_t sector,
void **kaddr, pfn_t *pfn, long size)
{
return -EIO;
}
static struct target_type error_target = {
.name = "error",
.version = {1, 5, 0},
.features = DM_TARGET_WILDCARD,
.ctr = io_err_ctr,
.dtr = io_err_dtr,
.map = io_err_map,
.map_rq = io_err_map_rq,
.clone_and_map_rq = io_err_clone_and_map_rq,
.release_clone_rq = io_err_release_clone_rq,
.direct_access = io_err_direct_access,
};
int __init dm_target_init(void)
{
return dm_register_target(&error_target);
}
void dm_target_exit(void)
{
dm_unregister_target(&error_target);
}
EXPORT_SYMBOL(dm_register_target);
EXPORT_SYMBOL(dm_unregister_target);