--- /dev/null
+/*
+ * 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 <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 void dcssblk_make_request(struct request_queue *q, struct bio *bio);
+static long dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
+ void **kaddr, unsigned long *pfn, long size);
+
+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,
+ .direct_access = dcssblk_direct_access,
+};
+
+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 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);
+
+ 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; (buf[j] != ':') &&
+ (buf[j] != '\0') &&
+ (buf[j] != '\n') &&
+ j < count; 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;
+ dev_info->gd->driverfs_dev = &dev_info->dev;
+ blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
+ blk_queue_logical_block_size(dev_info->dcssblk_queue, 4096);
+
+ 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;
+
+ get_device(&dev_info->dev);
+ add_disk(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; ((*(buf+i)!='\0') && (*(buf+i)!='\n') && i < count); 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_warning("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_warning("Device %s cannot be removed while it is in "
+ "use\n", local_buf);
+ rc = -EBUSY;
+ goto out_buf;
+ }
+
+ list_del(&dev_info->lh);
+ del_gendisk(dev_info->gd);
+ blk_cleanup_queue(dev_info->dcssblk_queue);
+ dev_info->gd->queue = NULL;
+ put_disk(dev_info->gd);
+ device_unregister(&dev_info->dev);
+
+ /* unload all related segments */
+ list_for_each_entry(entry, &dev_info->seg_list, lh)
+ segment_unload(entry->segment_name);
+
+ put_device(&dev_info->dev);
+ up_write(&dcssblk_devices_sem);
+
+ 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 void
+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;
+
+ bytes_done = 0;
+ dev_info = bio->bi_bdev->bd_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_bdev->bd_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_warning("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, 0);
+ return;
+fail:
+ bio_io_error(bio);
+}
+
+static long
+dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
+ void **kaddr, unsigned long *pfn, long size)
+{
+ struct dcssblk_dev_info *dev_info;
+ unsigned long offset, dev_sz;
+
+ dev_info = bdev->bd_disk->private_data;
+ if (!dev_info)
+ return -ENODEV;
+ dev_sz = dev_info->end - dev_info->start;
+ offset = secnum * 512;
+ *kaddr = (void *) (dev_info->start + offset);
+ *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
+
+ return dev_sz - offset;
+}
+
+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; (dcssblk_segments[j] != ',') &&
+ (dcssblk_segments[j] != '\0') &&
+ (dcssblk_segments[j] != '(') &&
+ (j < DCSSBLK_PARM_LEN); 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");
Code Review / kvmfornfv.git / blobdiff