linux/drivers/s390/block/dcssblk.c
Christoph Hellwig 74d46992e0 block: replace bi_bdev with a gendisk pointer and partitions index
This way we don't need a block_device structure to submit I/O.  The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open.  Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).

For the actual I/O path all that we need is the gendisk, which exists
once per block device.  But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.

Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23 12:49:55 -06:00

1126 lines
27 KiB
C

/*
* dcssblk.c -- the S/390 block driver for dcss memory
*
* Authors: Carsten Otte, Stefan Weinhuber, Gerald Schaefer
*/
#define KMSG_COMPONENT "dcssblk"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/completion.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/pfn_t.h>
#include <linux/uio.h>
#include <linux/dax.h>
#include <asm/extmem.h>
#include <asm/io.h>
#define DCSSBLK_NAME "dcssblk"
#define DCSSBLK_MINORS_PER_DISK 1
#define DCSSBLK_PARM_LEN 400
#define DCSS_BUS_ID_SIZE 20
static int dcssblk_open(struct block_device *bdev, fmode_t mode);
static void dcssblk_release(struct gendisk *disk, fmode_t mode);
static blk_qc_t dcssblk_make_request(struct request_queue *q,
struct bio *bio);
static long dcssblk_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn);
static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
static int dcssblk_major;
static const struct block_device_operations dcssblk_devops = {
.owner = THIS_MODULE,
.open = dcssblk_open,
.release = dcssblk_release,
};
static size_t dcssblk_dax_copy_from_iter(struct dax_device *dax_dev,
pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
{
return copy_from_iter(addr, bytes, i);
}
static const struct dax_operations dcssblk_dax_ops = {
.direct_access = dcssblk_dax_direct_access,
.copy_from_iter = dcssblk_dax_copy_from_iter,
};
struct dcssblk_dev_info {
struct list_head lh;
struct device dev;
char segment_name[DCSS_BUS_ID_SIZE];
atomic_t use_count;
struct gendisk *gd;
unsigned long start;
unsigned long end;
int segment_type;
unsigned char save_pending;
unsigned char is_shared;
struct request_queue *dcssblk_queue;
int num_of_segments;
struct list_head seg_list;
struct dax_device *dax_dev;
};
struct segment_info {
struct list_head lh;
char segment_name[DCSS_BUS_ID_SIZE];
unsigned long start;
unsigned long end;
int segment_type;
};
static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf,
size_t count);
static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf,
size_t count);
static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
static struct device *dcssblk_root_dev;
static LIST_HEAD(dcssblk_devices);
static struct rw_semaphore dcssblk_devices_sem;
/*
* release function for segment device.
*/
static void
dcssblk_release_segment(struct device *dev)
{
struct dcssblk_dev_info *dev_info;
struct segment_info *entry, *temp;
dev_info = container_of(dev, struct dcssblk_dev_info, dev);
list_for_each_entry_safe(entry, temp, &dev_info->seg_list, lh) {
list_del(&entry->lh);
kfree(entry);
}
kfree(dev_info);
module_put(THIS_MODULE);
}
/*
* get a minor number. needs to be called with
* down_write(&dcssblk_devices_sem) and the
* device needs to be enqueued before the semaphore is
* freed.
*/
static int
dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
{
int minor, found;
struct dcssblk_dev_info *entry;
if (dev_info == NULL)
return -EINVAL;
for (minor = 0; minor < (1<<MINORBITS); minor++) {
found = 0;
// test if minor available
list_for_each_entry(entry, &dcssblk_devices, lh)
if (minor == entry->gd->first_minor)
found++;
if (!found) break; // got unused minor
}
if (found)
return -EBUSY;
dev_info->gd->first_minor = minor;
return 0;
}
/*
* get the struct dcssblk_dev_info from dcssblk_devices
* for the given name.
* down_read(&dcssblk_devices_sem) must be held.
*/
static struct dcssblk_dev_info *
dcssblk_get_device_by_name(char *name)
{
struct dcssblk_dev_info *entry;
list_for_each_entry(entry, &dcssblk_devices, lh) {
if (!strcmp(name, entry->segment_name)) {
return entry;
}
}
return NULL;
}
/*
* get the struct segment_info from seg_list
* for the given name.
* down_read(&dcssblk_devices_sem) must be held.
*/
static struct segment_info *
dcssblk_get_segment_by_name(char *name)
{
struct dcssblk_dev_info *dev_info;
struct segment_info *entry;
list_for_each_entry(dev_info, &dcssblk_devices, lh) {
list_for_each_entry(entry, &dev_info->seg_list, lh) {
if (!strcmp(name, entry->segment_name))
return entry;
}
}
return NULL;
}
/*
* get the highest address of the multi-segment block.
*/
static unsigned long
dcssblk_find_highest_addr(struct dcssblk_dev_info *dev_info)
{
unsigned long highest_addr;
struct segment_info *entry;
highest_addr = 0;
list_for_each_entry(entry, &dev_info->seg_list, lh) {
if (highest_addr < entry->end)
highest_addr = entry->end;
}
return highest_addr;
}
/*
* get the lowest address of the multi-segment block.
*/
static unsigned long
dcssblk_find_lowest_addr(struct dcssblk_dev_info *dev_info)
{
int set_first;
unsigned long lowest_addr;
struct segment_info *entry;
set_first = 0;
lowest_addr = 0;
list_for_each_entry(entry, &dev_info->seg_list, lh) {
if (set_first == 0) {
lowest_addr = entry->start;
set_first = 1;
} else {
if (lowest_addr > entry->start)
lowest_addr = entry->start;
}
}
return lowest_addr;
}
/*
* Check continuity of segments.
*/
static int
dcssblk_is_continuous(struct dcssblk_dev_info *dev_info)
{
int i, j, rc;
struct segment_info *sort_list, *entry, temp;
if (dev_info->num_of_segments <= 1)
return 0;
sort_list = kzalloc(
sizeof(struct segment_info) * dev_info->num_of_segments,
GFP_KERNEL);
if (sort_list == NULL)
return -ENOMEM;
i = 0;
list_for_each_entry(entry, &dev_info->seg_list, lh) {
memcpy(&sort_list[i], entry, sizeof(struct segment_info));
i++;
}
/* sort segments */
for (i = 0; i < dev_info->num_of_segments; i++)
for (j = 0; j < dev_info->num_of_segments; j++)
if (sort_list[j].start > sort_list[i].start) {
memcpy(&temp, &sort_list[i],
sizeof(struct segment_info));
memcpy(&sort_list[i], &sort_list[j],
sizeof(struct segment_info));
memcpy(&sort_list[j], &temp,
sizeof(struct segment_info));
}
/* check continuity */
for (i = 0; i < dev_info->num_of_segments - 1; i++) {
if ((sort_list[i].end + 1) != sort_list[i+1].start) {
pr_err("Adjacent DCSSs %s and %s are not "
"contiguous\n", sort_list[i].segment_name,
sort_list[i+1].segment_name);
rc = -EINVAL;
goto out;
}
/* EN and EW are allowed in a block device */
if (sort_list[i].segment_type != sort_list[i+1].segment_type) {
if (!(sort_list[i].segment_type & SEGMENT_EXCLUSIVE) ||
(sort_list[i].segment_type == SEG_TYPE_ER) ||
!(sort_list[i+1].segment_type &
SEGMENT_EXCLUSIVE) ||
(sort_list[i+1].segment_type == SEG_TYPE_ER)) {
pr_err("DCSS %s and DCSS %s have "
"incompatible types\n",
sort_list[i].segment_name,
sort_list[i+1].segment_name);
rc = -EINVAL;
goto out;
}
}
}
rc = 0;
out:
kfree(sort_list);
return rc;
}
/*
* Load a segment
*/
static int
dcssblk_load_segment(char *name, struct segment_info **seg_info)
{
int rc;
/* already loaded? */
down_read(&dcssblk_devices_sem);
*seg_info = dcssblk_get_segment_by_name(name);
up_read(&dcssblk_devices_sem);
if (*seg_info != NULL)
return -EEXIST;
/* get a struct segment_info */
*seg_info = kzalloc(sizeof(struct segment_info), GFP_KERNEL);
if (*seg_info == NULL)
return -ENOMEM;
strcpy((*seg_info)->segment_name, name);
/* load the segment */
rc = segment_load(name, SEGMENT_SHARED,
&(*seg_info)->start, &(*seg_info)->end);
if (rc < 0) {
segment_warning(rc, (*seg_info)->segment_name);
kfree(*seg_info);
} else {
INIT_LIST_HEAD(&(*seg_info)->lh);
(*seg_info)->segment_type = rc;
}
return rc;
}
/*
* device attribute for switching shared/nonshared (exclusive)
* operation (show + store)
*/
static ssize_t
dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct dcssblk_dev_info *dev_info;
dev_info = container_of(dev, struct dcssblk_dev_info, dev);
return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
}
static ssize_t
dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
{
struct dcssblk_dev_info *dev_info;
struct segment_info *entry, *temp;
int rc;
if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
return -EINVAL;
down_write(&dcssblk_devices_sem);
dev_info = container_of(dev, struct dcssblk_dev_info, dev);
if (atomic_read(&dev_info->use_count)) {
rc = -EBUSY;
goto out;
}
if (inbuf[0] == '1') {
/* reload segments in shared mode */
list_for_each_entry(entry, &dev_info->seg_list, lh) {
rc = segment_modify_shared(entry->segment_name,
SEGMENT_SHARED);
if (rc < 0) {
BUG_ON(rc == -EINVAL);
if (rc != -EAGAIN)
goto removeseg;
}
}
dev_info->is_shared = 1;
switch (dev_info->segment_type) {
case SEG_TYPE_SR:
case SEG_TYPE_ER:
case SEG_TYPE_SC:
set_disk_ro(dev_info->gd, 1);
}
} else if (inbuf[0] == '0') {
/* reload segments in exclusive mode */
if (dev_info->segment_type == SEG_TYPE_SC) {
pr_err("DCSS %s is of type SC and cannot be "
"loaded as exclusive-writable\n",
dev_info->segment_name);
rc = -EINVAL;
goto out;
}
list_for_each_entry(entry, &dev_info->seg_list, lh) {
rc = segment_modify_shared(entry->segment_name,
SEGMENT_EXCLUSIVE);
if (rc < 0) {
BUG_ON(rc == -EINVAL);
if (rc != -EAGAIN)
goto removeseg;
}
}
dev_info->is_shared = 0;
set_disk_ro(dev_info->gd, 0);
} else {
rc = -EINVAL;
goto out;
}
rc = count;
goto out;
removeseg:
pr_err("DCSS device %s is removed after a failed access mode "
"change\n", dev_info->segment_name);
temp = entry;
list_for_each_entry(entry, &dev_info->seg_list, lh) {
if (entry != temp)
segment_unload(entry->segment_name);
}
list_del(&dev_info->lh);
kill_dax(dev_info->dax_dev);
put_dax(dev_info->dax_dev);
del_gendisk(dev_info->gd);
blk_cleanup_queue(dev_info->dcssblk_queue);
dev_info->gd->queue = NULL;
put_disk(dev_info->gd);
up_write(&dcssblk_devices_sem);
if (device_remove_file_self(dev, attr)) {
device_unregister(dev);
put_device(dev);
}
return rc;
out:
up_write(&dcssblk_devices_sem);
return rc;
}
static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show,
dcssblk_shared_store);
/*
* device attribute for save operation on current copy
* of the segment. If the segment is busy, saving will
* become pending until it gets released, which can be
* undone by storing a non-true value to this entry.
* (show + store)
*/
static ssize_t
dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct dcssblk_dev_info *dev_info;
dev_info = container_of(dev, struct dcssblk_dev_info, dev);
return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
}
static ssize_t
dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
{
struct dcssblk_dev_info *dev_info;
struct segment_info *entry;
if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
return -EINVAL;
dev_info = container_of(dev, struct dcssblk_dev_info, dev);
down_write(&dcssblk_devices_sem);
if (inbuf[0] == '1') {
if (atomic_read(&dev_info->use_count) == 0) {
// device is idle => we save immediately
pr_info("All DCSSs that map to device %s are "
"saved\n", dev_info->segment_name);
list_for_each_entry(entry, &dev_info->seg_list, lh) {
if (entry->segment_type == SEG_TYPE_EN ||
entry->segment_type == SEG_TYPE_SN)
pr_warn("DCSS %s is of type SN or EN"
" and cannot be saved\n",
entry->segment_name);
else
segment_save(entry->segment_name);
}
} else {
// device is busy => we save it when it becomes
// idle in dcssblk_release
pr_info("Device %s is in use, its DCSSs will be "
"saved when it becomes idle\n",
dev_info->segment_name);
dev_info->save_pending = 1;
}
} else if (inbuf[0] == '0') {
if (dev_info->save_pending) {
// device is busy & the user wants to undo his save
// request
dev_info->save_pending = 0;
pr_info("A pending save request for device %s "
"has been canceled\n",
dev_info->segment_name);
}
} else {
up_write(&dcssblk_devices_sem);
return -EINVAL;
}
up_write(&dcssblk_devices_sem);
return count;
}
static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show,
dcssblk_save_store);
/*
* device attribute for showing all segments in a device
*/
static ssize_t
dcssblk_seglist_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
int i;
struct dcssblk_dev_info *dev_info;
struct segment_info *entry;
down_read(&dcssblk_devices_sem);
dev_info = container_of(dev, struct dcssblk_dev_info, dev);
i = 0;
buf[0] = '\0';
list_for_each_entry(entry, &dev_info->seg_list, lh) {
strcpy(&buf[i], entry->segment_name);
i += strlen(entry->segment_name);
buf[i] = '\n';
i++;
}
up_read(&dcssblk_devices_sem);
return i;
}
static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL);
static struct attribute *dcssblk_dev_attrs[] = {
&dev_attr_shared.attr,
&dev_attr_save.attr,
&dev_attr_seglist.attr,
NULL,
};
static struct attribute_group dcssblk_dev_attr_group = {
.attrs = dcssblk_dev_attrs,
};
static const struct attribute_group *dcssblk_dev_attr_groups[] = {
&dcssblk_dev_attr_group,
NULL,
};
/*
* device attribute for adding devices
*/
static ssize_t
dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
int rc, i, j, num_of_segments;
struct dcssblk_dev_info *dev_info;
struct segment_info *seg_info, *temp;
char *local_buf;
unsigned long seg_byte_size;
dev_info = NULL;
seg_info = NULL;
if (dev != dcssblk_root_dev) {
rc = -EINVAL;
goto out_nobuf;
}
if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) {
rc = -ENAMETOOLONG;
goto out_nobuf;
}
local_buf = kmalloc(count + 1, GFP_KERNEL);
if (local_buf == NULL) {
rc = -ENOMEM;
goto out_nobuf;
}
/*
* parse input
*/
num_of_segments = 0;
for (i = 0; (i < count && (buf[i] != '\0') && (buf[i] != '\n')); i++) {
for (j = i; j < count &&
(buf[j] != ':') &&
(buf[j] != '\0') &&
(buf[j] != '\n'); j++) {
local_buf[j-i] = toupper(buf[j]);
}
local_buf[j-i] = '\0';
if (((j - i) == 0) || ((j - i) > 8)) {
rc = -ENAMETOOLONG;
goto seg_list_del;
}
rc = dcssblk_load_segment(local_buf, &seg_info);
if (rc < 0)
goto seg_list_del;
/*
* get a struct dcssblk_dev_info
*/
if (num_of_segments == 0) {
dev_info = kzalloc(sizeof(struct dcssblk_dev_info),
GFP_KERNEL);
if (dev_info == NULL) {
rc = -ENOMEM;
goto out;
}
strcpy(dev_info->segment_name, local_buf);
dev_info->segment_type = seg_info->segment_type;
INIT_LIST_HEAD(&dev_info->seg_list);
}
list_add_tail(&seg_info->lh, &dev_info->seg_list);
num_of_segments++;
i = j;
if ((buf[j] == '\0') || (buf[j] == '\n'))
break;
}
/* no trailing colon at the end of the input */
if ((i > 0) && (buf[i-1] == ':')) {
rc = -ENAMETOOLONG;
goto seg_list_del;
}
strlcpy(local_buf, buf, i + 1);
dev_info->num_of_segments = num_of_segments;
rc = dcssblk_is_continuous(dev_info);
if (rc < 0)
goto seg_list_del;
dev_info->start = dcssblk_find_lowest_addr(dev_info);
dev_info->end = dcssblk_find_highest_addr(dev_info);
dev_set_name(&dev_info->dev, "%s", dev_info->segment_name);
dev_info->dev.release = dcssblk_release_segment;
dev_info->dev.groups = dcssblk_dev_attr_groups;
INIT_LIST_HEAD(&dev_info->lh);
dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
if (dev_info->gd == NULL) {
rc = -ENOMEM;
goto seg_list_del;
}
dev_info->gd->major = dcssblk_major;
dev_info->gd->fops = &dcssblk_devops;
dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
dev_info->gd->queue = dev_info->dcssblk_queue;
dev_info->gd->private_data = dev_info;
blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
blk_queue_logical_block_size(dev_info->dcssblk_queue, 4096);
queue_flag_set_unlocked(QUEUE_FLAG_DAX, dev_info->dcssblk_queue);
seg_byte_size = (dev_info->end - dev_info->start + 1);
set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
pr_info("Loaded %s with total size %lu bytes and capacity %lu "
"sectors\n", local_buf, seg_byte_size, seg_byte_size >> 9);
dev_info->save_pending = 0;
dev_info->is_shared = 1;
dev_info->dev.parent = dcssblk_root_dev;
/*
*get minor, add to list
*/
down_write(&dcssblk_devices_sem);
if (dcssblk_get_segment_by_name(local_buf)) {
rc = -EEXIST;
goto release_gd;
}
rc = dcssblk_assign_free_minor(dev_info);
if (rc)
goto release_gd;
sprintf(dev_info->gd->disk_name, "dcssblk%d",
dev_info->gd->first_minor);
list_add_tail(&dev_info->lh, &dcssblk_devices);
if (!try_module_get(THIS_MODULE)) {
rc = -ENODEV;
goto dev_list_del;
}
/*
* register the device
*/
rc = device_register(&dev_info->dev);
if (rc)
goto put_dev;
dev_info->dax_dev = alloc_dax(dev_info, dev_info->gd->disk_name,
&dcssblk_dax_ops);
if (!dev_info->dax_dev) {
rc = -ENOMEM;
goto put_dev;
}
get_device(&dev_info->dev);
device_add_disk(&dev_info->dev, dev_info->gd);
switch (dev_info->segment_type) {
case SEG_TYPE_SR:
case SEG_TYPE_ER:
case SEG_TYPE_SC:
set_disk_ro(dev_info->gd,1);
break;
default:
set_disk_ro(dev_info->gd,0);
break;
}
up_write(&dcssblk_devices_sem);
rc = count;
goto out;
put_dev:
list_del(&dev_info->lh);
blk_cleanup_queue(dev_info->dcssblk_queue);
dev_info->gd->queue = NULL;
put_disk(dev_info->gd);
list_for_each_entry(seg_info, &dev_info->seg_list, lh) {
segment_unload(seg_info->segment_name);
}
put_device(&dev_info->dev);
up_write(&dcssblk_devices_sem);
goto out;
dev_list_del:
list_del(&dev_info->lh);
release_gd:
blk_cleanup_queue(dev_info->dcssblk_queue);
dev_info->gd->queue = NULL;
put_disk(dev_info->gd);
up_write(&dcssblk_devices_sem);
seg_list_del:
if (dev_info == NULL)
goto out;
list_for_each_entry_safe(seg_info, temp, &dev_info->seg_list, lh) {
list_del(&seg_info->lh);
segment_unload(seg_info->segment_name);
kfree(seg_info);
}
kfree(dev_info);
out:
kfree(local_buf);
out_nobuf:
return rc;
}
/*
* device attribute for removing devices
*/
static ssize_t
dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
struct dcssblk_dev_info *dev_info;
struct segment_info *entry;
int rc, i;
char *local_buf;
if (dev != dcssblk_root_dev) {
return -EINVAL;
}
local_buf = kmalloc(count + 1, GFP_KERNEL);
if (local_buf == NULL) {
return -ENOMEM;
}
/*
* parse input
*/
for (i = 0; (i < count && (*(buf+i)!='\0') && (*(buf+i)!='\n')); i++) {
local_buf[i] = toupper(buf[i]);
}
local_buf[i] = '\0';
if ((i == 0) || (i > 8)) {
rc = -ENAMETOOLONG;
goto out_buf;
}
down_write(&dcssblk_devices_sem);
dev_info = dcssblk_get_device_by_name(local_buf);
if (dev_info == NULL) {
up_write(&dcssblk_devices_sem);
pr_warn("Device %s cannot be removed because it is not a known device\n",
local_buf);
rc = -ENODEV;
goto out_buf;
}
if (atomic_read(&dev_info->use_count) != 0) {
up_write(&dcssblk_devices_sem);
pr_warn("Device %s cannot be removed while it is in use\n",
local_buf);
rc = -EBUSY;
goto out_buf;
}
list_del(&dev_info->lh);
kill_dax(dev_info->dax_dev);
put_dax(dev_info->dax_dev);
del_gendisk(dev_info->gd);
blk_cleanup_queue(dev_info->dcssblk_queue);
dev_info->gd->queue = NULL;
put_disk(dev_info->gd);
/* unload all related segments */
list_for_each_entry(entry, &dev_info->seg_list, lh)
segment_unload(entry->segment_name);
up_write(&dcssblk_devices_sem);
device_unregister(&dev_info->dev);
put_device(&dev_info->dev);
rc = count;
out_buf:
kfree(local_buf);
return rc;
}
static int
dcssblk_open(struct block_device *bdev, fmode_t mode)
{
struct dcssblk_dev_info *dev_info;
int rc;
dev_info = bdev->bd_disk->private_data;
if (NULL == dev_info) {
rc = -ENODEV;
goto out;
}
atomic_inc(&dev_info->use_count);
bdev->bd_block_size = 4096;
rc = 0;
out:
return rc;
}
static void
dcssblk_release(struct gendisk *disk, fmode_t mode)
{
struct dcssblk_dev_info *dev_info = disk->private_data;
struct segment_info *entry;
if (!dev_info) {
WARN_ON(1);
return;
}
down_write(&dcssblk_devices_sem);
if (atomic_dec_and_test(&dev_info->use_count)
&& (dev_info->save_pending)) {
pr_info("Device %s has become idle and is being saved "
"now\n", dev_info->segment_name);
list_for_each_entry(entry, &dev_info->seg_list, lh) {
if (entry->segment_type == SEG_TYPE_EN ||
entry->segment_type == SEG_TYPE_SN)
pr_warn("DCSS %s is of type SN or EN and cannot"
" be saved\n", entry->segment_name);
else
segment_save(entry->segment_name);
}
dev_info->save_pending = 0;
}
up_write(&dcssblk_devices_sem);
}
static blk_qc_t
dcssblk_make_request(struct request_queue *q, struct bio *bio)
{
struct dcssblk_dev_info *dev_info;
struct bio_vec bvec;
struct bvec_iter iter;
unsigned long index;
unsigned long page_addr;
unsigned long source_addr;
unsigned long bytes_done;
blk_queue_split(q, &bio);
bytes_done = 0;
dev_info = bio->bi_disk->private_data;
if (dev_info == NULL)
goto fail;
if ((bio->bi_iter.bi_sector & 7) != 0 ||
(bio->bi_iter.bi_size & 4095) != 0)
/* Request is not page-aligned. */
goto fail;
if (bio_end_sector(bio) > get_capacity(bio->bi_disk)) {
/* Request beyond end of DCSS segment. */
goto fail;
}
/* verify data transfer direction */
if (dev_info->is_shared) {
switch (dev_info->segment_type) {
case SEG_TYPE_SR:
case SEG_TYPE_ER:
case SEG_TYPE_SC:
/* cannot write to these segments */
if (bio_data_dir(bio) == WRITE) {
pr_warn("Writing to %s failed because it is a read-only device\n",
dev_name(&dev_info->dev));
goto fail;
}
}
}
index = (bio->bi_iter.bi_sector >> 3);
bio_for_each_segment(bvec, bio, iter) {
page_addr = (unsigned long)
page_address(bvec.bv_page) + bvec.bv_offset;
source_addr = dev_info->start + (index<<12) + bytes_done;
if (unlikely((page_addr & 4095) != 0) || (bvec.bv_len & 4095) != 0)
// More paranoia.
goto fail;
if (bio_data_dir(bio) == READ) {
memcpy((void*)page_addr, (void*)source_addr,
bvec.bv_len);
} else {
memcpy((void*)source_addr, (void*)page_addr,
bvec.bv_len);
}
bytes_done += bvec.bv_len;
}
bio_endio(bio);
return BLK_QC_T_NONE;
fail:
bio_io_error(bio);
return BLK_QC_T_NONE;
}
static long
__dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
resource_size_t offset = pgoff * PAGE_SIZE;
unsigned long dev_sz;
dev_sz = dev_info->end - dev_info->start + 1;
*kaddr = (void *) dev_info->start + offset;
*pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), PFN_DEV);
return (dev_sz - offset) / PAGE_SIZE;
}
static long
dcssblk_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
struct dcssblk_dev_info *dev_info = dax_get_private(dax_dev);
return __dcssblk_direct_access(dev_info, pgoff, nr_pages, kaddr, pfn);
}
static void
dcssblk_check_params(void)
{
int rc, i, j, k;
char buf[DCSSBLK_PARM_LEN + 1];
struct dcssblk_dev_info *dev_info;
for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
i++) {
for (j = i; (j < DCSSBLK_PARM_LEN) &&
(dcssblk_segments[j] != ',') &&
(dcssblk_segments[j] != '\0') &&
(dcssblk_segments[j] != '('); j++)
{
buf[j-i] = dcssblk_segments[j];
}
buf[j-i] = '\0';
rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++)
buf[k] = toupper(buf[k]);
buf[k] = '\0';
if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
down_read(&dcssblk_devices_sem);
dev_info = dcssblk_get_device_by_name(buf);
up_read(&dcssblk_devices_sem);
if (dev_info)
dcssblk_shared_store(&dev_info->dev,
NULL, "0\n", 2);
}
}
while ((dcssblk_segments[j] != ',') &&
(dcssblk_segments[j] != '\0'))
{
j++;
}
if (dcssblk_segments[j] == '\0')
break;
i = j;
}
}
/*
* Suspend / Resume
*/
static int dcssblk_freeze(struct device *dev)
{
struct dcssblk_dev_info *dev_info;
int rc = 0;
list_for_each_entry(dev_info, &dcssblk_devices, lh) {
switch (dev_info->segment_type) {
case SEG_TYPE_SR:
case SEG_TYPE_ER:
case SEG_TYPE_SC:
if (!dev_info->is_shared)
rc = -EINVAL;
break;
default:
rc = -EINVAL;
break;
}
if (rc)
break;
}
if (rc)
pr_err("Suspending the system failed because DCSS device %s "
"is writable\n",
dev_info->segment_name);
return rc;
}
static int dcssblk_restore(struct device *dev)
{
struct dcssblk_dev_info *dev_info;
struct segment_info *entry;
unsigned long start, end;
int rc = 0;
list_for_each_entry(dev_info, &dcssblk_devices, lh) {
list_for_each_entry(entry, &dev_info->seg_list, lh) {
segment_unload(entry->segment_name);
rc = segment_load(entry->segment_name, SEGMENT_SHARED,
&start, &end);
if (rc < 0) {
// TODO in_use check ?
segment_warning(rc, entry->segment_name);
goto out_panic;
}
if (start != entry->start || end != entry->end) {
pr_err("The address range of DCSS %s changed "
"while the system was suspended\n",
entry->segment_name);
goto out_panic;
}
}
}
return 0;
out_panic:
panic("fatal dcssblk resume error\n");
}
static int dcssblk_thaw(struct device *dev)
{
return 0;
}
static const struct dev_pm_ops dcssblk_pm_ops = {
.freeze = dcssblk_freeze,
.thaw = dcssblk_thaw,
.restore = dcssblk_restore,
};
static struct platform_driver dcssblk_pdrv = {
.driver = {
.name = "dcssblk",
.pm = &dcssblk_pm_ops,
},
};
static struct platform_device *dcssblk_pdev;
/*
* The init/exit functions.
*/
static void __exit
dcssblk_exit(void)
{
platform_device_unregister(dcssblk_pdev);
platform_driver_unregister(&dcssblk_pdrv);
root_device_unregister(dcssblk_root_dev);
unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
}
static int __init
dcssblk_init(void)
{
int rc;
rc = platform_driver_register(&dcssblk_pdrv);
if (rc)
return rc;
dcssblk_pdev = platform_device_register_simple("dcssblk", -1, NULL,
0);
if (IS_ERR(dcssblk_pdev)) {
rc = PTR_ERR(dcssblk_pdev);
goto out_pdrv;
}
dcssblk_root_dev = root_device_register("dcssblk");
if (IS_ERR(dcssblk_root_dev)) {
rc = PTR_ERR(dcssblk_root_dev);
goto out_pdev;
}
rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
if (rc)
goto out_root;
rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
if (rc)
goto out_root;
rc = register_blkdev(0, DCSSBLK_NAME);
if (rc < 0)
goto out_root;
dcssblk_major = rc;
init_rwsem(&dcssblk_devices_sem);
dcssblk_check_params();
return 0;
out_root:
root_device_unregister(dcssblk_root_dev);
out_pdev:
platform_device_unregister(dcssblk_pdev);
out_pdrv:
platform_driver_unregister(&dcssblk_pdrv);
return rc;
}
module_init(dcssblk_init);
module_exit(dcssblk_exit);
module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
"comma-separated list, names in each set separated "
"by commas are separated by colons, each set contains "
"names of contiguous segments and each name max. 8 chars.\n"
"Adding \"(local)\" to the end of each set equals echoing 0 "
"to /sys/devices/dcssblk/<device name>/shared after loading "
"the contiguous segments - \n"
"e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\"");
MODULE_LICENSE("GPL");