![Kirill A. Shutemov](/assets/img/avatar_default.png)
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
596 lines
15 KiB
C
596 lines
15 KiB
C
/*
|
|
* Code extracted from drivers/block/genhd.c
|
|
* Copyright (C) 1991-1998 Linus Torvalds
|
|
* Re-organised Feb 1998 Russell King
|
|
*
|
|
* We now have independent partition support from the
|
|
* block drivers, which allows all the partition code to
|
|
* be grouped in one location, and it to be mostly self
|
|
* contained.
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/module.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/kmod.h>
|
|
#include <linux/ctype.h>
|
|
#include <linux/genhd.h>
|
|
#include <linux/dax.h>
|
|
#include <linux/blktrace_api.h>
|
|
|
|
#include "partitions/check.h"
|
|
|
|
#ifdef CONFIG_BLK_DEV_MD
|
|
extern void md_autodetect_dev(dev_t dev);
|
|
#endif
|
|
|
|
/*
|
|
* disk_name() is used by partition check code and the genhd driver.
|
|
* It formats the devicename of the indicated disk into
|
|
* the supplied buffer (of size at least 32), and returns
|
|
* a pointer to that same buffer (for convenience).
|
|
*/
|
|
|
|
char *disk_name(struct gendisk *hd, int partno, char *buf)
|
|
{
|
|
if (!partno)
|
|
snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
|
|
else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
|
|
snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
|
|
else
|
|
snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
|
|
|
|
return buf;
|
|
}
|
|
|
|
const char *bdevname(struct block_device *bdev, char *buf)
|
|
{
|
|
return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
|
|
}
|
|
|
|
EXPORT_SYMBOL(bdevname);
|
|
|
|
/*
|
|
* There's very little reason to use this, you should really
|
|
* have a struct block_device just about everywhere and use
|
|
* bdevname() instead.
|
|
*/
|
|
const char *__bdevname(dev_t dev, char *buffer)
|
|
{
|
|
scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
|
|
MAJOR(dev), MINOR(dev));
|
|
return buffer;
|
|
}
|
|
|
|
EXPORT_SYMBOL(__bdevname);
|
|
|
|
static ssize_t part_partition_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
|
|
return sprintf(buf, "%d\n", p->partno);
|
|
}
|
|
|
|
static ssize_t part_start_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
|
|
return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
|
|
}
|
|
|
|
ssize_t part_size_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
return sprintf(buf, "%llu\n",(unsigned long long)part_nr_sects_read(p));
|
|
}
|
|
|
|
static ssize_t part_ro_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
return sprintf(buf, "%d\n", p->policy ? 1 : 0);
|
|
}
|
|
|
|
static ssize_t part_alignment_offset_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
|
|
}
|
|
|
|
static ssize_t part_discard_alignment_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
return sprintf(buf, "%u\n", p->discard_alignment);
|
|
}
|
|
|
|
ssize_t part_stat_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
int cpu;
|
|
|
|
cpu = part_stat_lock();
|
|
part_round_stats(cpu, p);
|
|
part_stat_unlock();
|
|
return sprintf(buf,
|
|
"%8lu %8lu %8llu %8u "
|
|
"%8lu %8lu %8llu %8u "
|
|
"%8u %8u %8u"
|
|
"\n",
|
|
part_stat_read(p, ios[READ]),
|
|
part_stat_read(p, merges[READ]),
|
|
(unsigned long long)part_stat_read(p, sectors[READ]),
|
|
jiffies_to_msecs(part_stat_read(p, ticks[READ])),
|
|
part_stat_read(p, ios[WRITE]),
|
|
part_stat_read(p, merges[WRITE]),
|
|
(unsigned long long)part_stat_read(p, sectors[WRITE]),
|
|
jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
|
|
part_in_flight(p),
|
|
jiffies_to_msecs(part_stat_read(p, io_ticks)),
|
|
jiffies_to_msecs(part_stat_read(p, time_in_queue)));
|
|
}
|
|
|
|
ssize_t part_inflight_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
|
|
return sprintf(buf, "%8u %8u\n", atomic_read(&p->in_flight[0]),
|
|
atomic_read(&p->in_flight[1]));
|
|
}
|
|
|
|
#ifdef CONFIG_FAIL_MAKE_REQUEST
|
|
ssize_t part_fail_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
|
|
return sprintf(buf, "%d\n", p->make_it_fail);
|
|
}
|
|
|
|
ssize_t part_fail_store(struct device *dev,
|
|
struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
int i;
|
|
|
|
if (count > 0 && sscanf(buf, "%d", &i) > 0)
|
|
p->make_it_fail = (i == 0) ? 0 : 1;
|
|
|
|
return count;
|
|
}
|
|
#endif
|
|
|
|
static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
|
|
static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
|
|
static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
|
|
static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
|
|
static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
|
|
static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
|
|
NULL);
|
|
static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
|
|
static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
|
|
#ifdef CONFIG_FAIL_MAKE_REQUEST
|
|
static struct device_attribute dev_attr_fail =
|
|
__ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
|
|
#endif
|
|
|
|
static struct attribute *part_attrs[] = {
|
|
&dev_attr_partition.attr,
|
|
&dev_attr_start.attr,
|
|
&dev_attr_size.attr,
|
|
&dev_attr_ro.attr,
|
|
&dev_attr_alignment_offset.attr,
|
|
&dev_attr_discard_alignment.attr,
|
|
&dev_attr_stat.attr,
|
|
&dev_attr_inflight.attr,
|
|
#ifdef CONFIG_FAIL_MAKE_REQUEST
|
|
&dev_attr_fail.attr,
|
|
#endif
|
|
NULL
|
|
};
|
|
|
|
static struct attribute_group part_attr_group = {
|
|
.attrs = part_attrs,
|
|
};
|
|
|
|
static const struct attribute_group *part_attr_groups[] = {
|
|
&part_attr_group,
|
|
#ifdef CONFIG_BLK_DEV_IO_TRACE
|
|
&blk_trace_attr_group,
|
|
#endif
|
|
NULL
|
|
};
|
|
|
|
static void part_release(struct device *dev)
|
|
{
|
|
struct hd_struct *p = dev_to_part(dev);
|
|
blk_free_devt(dev->devt);
|
|
hd_free_part(p);
|
|
kfree(p);
|
|
}
|
|
|
|
static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
|
|
{
|
|
struct hd_struct *part = dev_to_part(dev);
|
|
|
|
add_uevent_var(env, "PARTN=%u", part->partno);
|
|
if (part->info && part->info->volname[0])
|
|
add_uevent_var(env, "PARTNAME=%s", part->info->volname);
|
|
return 0;
|
|
}
|
|
|
|
struct device_type part_type = {
|
|
.name = "partition",
|
|
.groups = part_attr_groups,
|
|
.release = part_release,
|
|
.uevent = part_uevent,
|
|
};
|
|
|
|
static void delete_partition_rcu_cb(struct rcu_head *head)
|
|
{
|
|
struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
|
|
|
|
part->start_sect = 0;
|
|
part->nr_sects = 0;
|
|
part_stat_set_all(part, 0);
|
|
put_device(part_to_dev(part));
|
|
}
|
|
|
|
void __delete_partition(struct percpu_ref *ref)
|
|
{
|
|
struct hd_struct *part = container_of(ref, struct hd_struct, ref);
|
|
call_rcu(&part->rcu_head, delete_partition_rcu_cb);
|
|
}
|
|
|
|
void delete_partition(struct gendisk *disk, int partno)
|
|
{
|
|
struct disk_part_tbl *ptbl = disk->part_tbl;
|
|
struct hd_struct *part;
|
|
|
|
if (partno >= ptbl->len)
|
|
return;
|
|
|
|
part = ptbl->part[partno];
|
|
if (!part)
|
|
return;
|
|
|
|
rcu_assign_pointer(ptbl->part[partno], NULL);
|
|
rcu_assign_pointer(ptbl->last_lookup, NULL);
|
|
kobject_put(part->holder_dir);
|
|
device_del(part_to_dev(part));
|
|
|
|
hd_struct_kill(part);
|
|
}
|
|
|
|
static ssize_t whole_disk_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
return 0;
|
|
}
|
|
static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
|
|
whole_disk_show, NULL);
|
|
|
|
struct hd_struct *add_partition(struct gendisk *disk, int partno,
|
|
sector_t start, sector_t len, int flags,
|
|
struct partition_meta_info *info)
|
|
{
|
|
struct hd_struct *p;
|
|
dev_t devt = MKDEV(0, 0);
|
|
struct device *ddev = disk_to_dev(disk);
|
|
struct device *pdev;
|
|
struct disk_part_tbl *ptbl;
|
|
const char *dname;
|
|
int err;
|
|
|
|
err = disk_expand_part_tbl(disk, partno);
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
ptbl = disk->part_tbl;
|
|
|
|
if (ptbl->part[partno])
|
|
return ERR_PTR(-EBUSY);
|
|
|
|
p = kzalloc(sizeof(*p), GFP_KERNEL);
|
|
if (!p)
|
|
return ERR_PTR(-EBUSY);
|
|
|
|
if (!init_part_stats(p)) {
|
|
err = -ENOMEM;
|
|
goto out_free;
|
|
}
|
|
|
|
seqcount_init(&p->nr_sects_seq);
|
|
pdev = part_to_dev(p);
|
|
|
|
p->start_sect = start;
|
|
p->alignment_offset =
|
|
queue_limit_alignment_offset(&disk->queue->limits, start);
|
|
p->discard_alignment =
|
|
queue_limit_discard_alignment(&disk->queue->limits, start);
|
|
p->nr_sects = len;
|
|
p->partno = partno;
|
|
p->policy = get_disk_ro(disk);
|
|
|
|
if (info) {
|
|
struct partition_meta_info *pinfo = alloc_part_info(disk);
|
|
if (!pinfo)
|
|
goto out_free_stats;
|
|
memcpy(pinfo, info, sizeof(*info));
|
|
p->info = pinfo;
|
|
}
|
|
|
|
dname = dev_name(ddev);
|
|
if (isdigit(dname[strlen(dname) - 1]))
|
|
dev_set_name(pdev, "%sp%d", dname, partno);
|
|
else
|
|
dev_set_name(pdev, "%s%d", dname, partno);
|
|
|
|
device_initialize(pdev);
|
|
pdev->class = &block_class;
|
|
pdev->type = &part_type;
|
|
pdev->parent = ddev;
|
|
|
|
err = blk_alloc_devt(p, &devt);
|
|
if (err)
|
|
goto out_free_info;
|
|
pdev->devt = devt;
|
|
|
|
/* delay uevent until 'holders' subdir is created */
|
|
dev_set_uevent_suppress(pdev, 1);
|
|
err = device_add(pdev);
|
|
if (err)
|
|
goto out_put;
|
|
|
|
err = -ENOMEM;
|
|
p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
|
|
if (!p->holder_dir)
|
|
goto out_del;
|
|
|
|
dev_set_uevent_suppress(pdev, 0);
|
|
if (flags & ADDPART_FLAG_WHOLEDISK) {
|
|
err = device_create_file(pdev, &dev_attr_whole_disk);
|
|
if (err)
|
|
goto out_del;
|
|
}
|
|
|
|
/* everything is up and running, commence */
|
|
rcu_assign_pointer(ptbl->part[partno], p);
|
|
|
|
/* suppress uevent if the disk suppresses it */
|
|
if (!dev_get_uevent_suppress(ddev))
|
|
kobject_uevent(&pdev->kobj, KOBJ_ADD);
|
|
|
|
if (!hd_ref_init(p))
|
|
return p;
|
|
|
|
out_free_info:
|
|
free_part_info(p);
|
|
out_free_stats:
|
|
free_part_stats(p);
|
|
out_free:
|
|
kfree(p);
|
|
return ERR_PTR(err);
|
|
out_del:
|
|
kobject_put(p->holder_dir);
|
|
device_del(pdev);
|
|
out_put:
|
|
put_device(pdev);
|
|
blk_free_devt(devt);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
static bool disk_unlock_native_capacity(struct gendisk *disk)
|
|
{
|
|
const struct block_device_operations *bdops = disk->fops;
|
|
|
|
if (bdops->unlock_native_capacity &&
|
|
!(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
|
|
printk(KERN_CONT "enabling native capacity\n");
|
|
bdops->unlock_native_capacity(disk);
|
|
disk->flags |= GENHD_FL_NATIVE_CAPACITY;
|
|
return true;
|
|
} else {
|
|
printk(KERN_CONT "truncated\n");
|
|
return false;
|
|
}
|
|
}
|
|
|
|
static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
|
|
{
|
|
struct disk_part_iter piter;
|
|
struct hd_struct *part;
|
|
int res;
|
|
|
|
if (bdev->bd_part_count || bdev->bd_super)
|
|
return -EBUSY;
|
|
res = invalidate_partition(disk, 0);
|
|
if (res)
|
|
return res;
|
|
|
|
disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
|
|
while ((part = disk_part_iter_next(&piter)))
|
|
delete_partition(disk, part->partno);
|
|
disk_part_iter_exit(&piter);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
|
|
{
|
|
struct parsed_partitions *state = NULL;
|
|
struct hd_struct *part;
|
|
int p, highest, res;
|
|
rescan:
|
|
if (state && !IS_ERR(state)) {
|
|
free_partitions(state);
|
|
state = NULL;
|
|
}
|
|
|
|
res = drop_partitions(disk, bdev);
|
|
if (res)
|
|
return res;
|
|
|
|
if (disk->fops->revalidate_disk)
|
|
disk->fops->revalidate_disk(disk);
|
|
blk_integrity_revalidate(disk);
|
|
check_disk_size_change(disk, bdev);
|
|
bdev->bd_invalidated = 0;
|
|
if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
|
|
return 0;
|
|
if (IS_ERR(state)) {
|
|
/*
|
|
* I/O error reading the partition table. If any
|
|
* partition code tried to read beyond EOD, retry
|
|
* after unlocking native capacity.
|
|
*/
|
|
if (PTR_ERR(state) == -ENOSPC) {
|
|
printk(KERN_WARNING "%s: partition table beyond EOD, ",
|
|
disk->disk_name);
|
|
if (disk_unlock_native_capacity(disk))
|
|
goto rescan;
|
|
}
|
|
return -EIO;
|
|
}
|
|
/*
|
|
* If any partition code tried to read beyond EOD, try
|
|
* unlocking native capacity even if partition table is
|
|
* successfully read as we could be missing some partitions.
|
|
*/
|
|
if (state->access_beyond_eod) {
|
|
printk(KERN_WARNING
|
|
"%s: partition table partially beyond EOD, ",
|
|
disk->disk_name);
|
|
if (disk_unlock_native_capacity(disk))
|
|
goto rescan;
|
|
}
|
|
|
|
/* tell userspace that the media / partition table may have changed */
|
|
kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
|
|
|
|
/* Detect the highest partition number and preallocate
|
|
* disk->part_tbl. This is an optimization and not strictly
|
|
* necessary.
|
|
*/
|
|
for (p = 1, highest = 0; p < state->limit; p++)
|
|
if (state->parts[p].size)
|
|
highest = p;
|
|
|
|
disk_expand_part_tbl(disk, highest);
|
|
|
|
/* add partitions */
|
|
for (p = 1; p < state->limit; p++) {
|
|
sector_t size, from;
|
|
struct partition_meta_info *info = NULL;
|
|
|
|
size = state->parts[p].size;
|
|
if (!size)
|
|
continue;
|
|
|
|
from = state->parts[p].from;
|
|
if (from >= get_capacity(disk)) {
|
|
printk(KERN_WARNING
|
|
"%s: p%d start %llu is beyond EOD, ",
|
|
disk->disk_name, p, (unsigned long long) from);
|
|
if (disk_unlock_native_capacity(disk))
|
|
goto rescan;
|
|
continue;
|
|
}
|
|
|
|
if (from + size > get_capacity(disk)) {
|
|
printk(KERN_WARNING
|
|
"%s: p%d size %llu extends beyond EOD, ",
|
|
disk->disk_name, p, (unsigned long long) size);
|
|
|
|
if (disk_unlock_native_capacity(disk)) {
|
|
/* free state and restart */
|
|
goto rescan;
|
|
} else {
|
|
/*
|
|
* we can not ignore partitions of broken tables
|
|
* created by for example camera firmware, but
|
|
* we limit them to the end of the disk to avoid
|
|
* creating invalid block devices
|
|
*/
|
|
size = get_capacity(disk) - from;
|
|
}
|
|
}
|
|
|
|
if (state->parts[p].has_info)
|
|
info = &state->parts[p].info;
|
|
part = add_partition(disk, p, from, size,
|
|
state->parts[p].flags,
|
|
&state->parts[p].info);
|
|
if (IS_ERR(part)) {
|
|
printk(KERN_ERR " %s: p%d could not be added: %ld\n",
|
|
disk->disk_name, p, -PTR_ERR(part));
|
|
continue;
|
|
}
|
|
#ifdef CONFIG_BLK_DEV_MD
|
|
if (state->parts[p].flags & ADDPART_FLAG_RAID)
|
|
md_autodetect_dev(part_to_dev(part)->devt);
|
|
#endif
|
|
}
|
|
free_partitions(state);
|
|
return 0;
|
|
}
|
|
|
|
int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
|
|
{
|
|
int res;
|
|
|
|
if (!bdev->bd_invalidated)
|
|
return 0;
|
|
|
|
res = drop_partitions(disk, bdev);
|
|
if (res)
|
|
return res;
|
|
|
|
set_capacity(disk, 0);
|
|
check_disk_size_change(disk, bdev);
|
|
bdev->bd_invalidated = 0;
|
|
/* tell userspace that the media / partition table may have changed */
|
|
kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct page *read_pagecache_sector(struct block_device *bdev, sector_t n)
|
|
{
|
|
struct address_space *mapping = bdev->bd_inode->i_mapping;
|
|
|
|
return read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)),
|
|
NULL);
|
|
}
|
|
|
|
unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
|
|
{
|
|
struct page *page;
|
|
|
|
/* don't populate page cache for dax capable devices */
|
|
if (IS_DAX(bdev->bd_inode))
|
|
page = read_dax_sector(bdev, n);
|
|
else
|
|
page = read_pagecache_sector(bdev, n);
|
|
|
|
if (!IS_ERR(page)) {
|
|
if (PageError(page))
|
|
goto fail;
|
|
p->v = page;
|
|
return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);
|
|
fail:
|
|
put_page(page);
|
|
}
|
|
p->v = NULL;
|
|
return NULL;
|
|
}
|
|
|
|
EXPORT_SYMBOL(read_dev_sector);
|