* Must use NOIO because we don't want to recurse back into the
* block or filesystem layers from page reclaim.
*
- * Cannot support XIP and highmem, because our ->direct_access
- * routine for XIP must return memory that is always addressable.
- * If XIP was reworked to use pfns and kmap throughout, this
+ * Cannot support DAX and highmem, because our ->direct_access
+ * routine for DAX must return memory that is always addressable.
+ * If DAX was reworked to use pfns and kmap throughout, this
* restriction might be able to be lifted.
*/
gfp_flags = GFP_NOIO | __GFP_ZERO;
-#ifndef CONFIG_BLK_DEV_XIP
+#ifndef CONFIG_BLK_DEV_RAM_DAX
gfp_flags |= __GFP_HIGHMEM;
#endif
page = alloc_page(gfp_flags);
return err;
}
-#ifdef CONFIG_BLK_DEV_XIP
-static int brd_direct_access(struct block_device *bdev, sector_t sector,
- void **kaddr, unsigned long *pfn)
+#ifdef CONFIG_BLK_DEV_RAM_DAX
+static long brd_direct_access(struct block_device *bdev, sector_t sector,
+ void **kaddr, unsigned long *pfn, long size)
{
struct brd_device *brd = bdev->bd_disk->private_data;
struct page *page;
if (!brd)
return -ENODEV;
- if (sector & (PAGE_SECTORS-1))
- return -EINVAL;
- if (sector + PAGE_SECTORS > get_capacity(bdev->bd_disk))
- return -ERANGE;
page = brd_insert_page(brd, sector);
if (!page)
return -ENOSPC;
*kaddr = page_address(page);
*pfn = page_to_pfn(page);
- return 0;
+ /*
+ * TODO: If size > PAGE_SIZE, we could look to see if the next page in
+ * the file happens to be mapped to the next page of physical RAM.
+ */
+ return PAGE_SIZE;
}
+#else
+#define brd_direct_access NULL
#endif
static int brd_ioctl(struct block_device *bdev, fmode_t mode,
.owner = THIS_MODULE,
.rw_page = brd_rw_page,
.ioctl = brd_ioctl,
-#ifdef CONFIG_BLK_DEV_XIP
.direct_access = brd_direct_access,
-#endif
};
/*
* And now the modules code and kernel interface.
*/
-static int rd_nr;
-int rd_size = CONFIG_BLK_DEV_RAM_SIZE;
-static int max_part;
-static int part_shift;
-static int part_show = 0;
+static int rd_nr = CONFIG_BLK_DEV_RAM_COUNT;
module_param(rd_nr, int, S_IRUGO);
MODULE_PARM_DESC(rd_nr, "Maximum number of brd devices");
+
+int rd_size = CONFIG_BLK_DEV_RAM_SIZE;
module_param(rd_size, int, S_IRUGO);
MODULE_PARM_DESC(rd_size, "Size of each RAM disk in kbytes.");
+
+static int max_part = 1;
module_param(max_part, int, S_IRUGO);
-MODULE_PARM_DESC(max_part, "Maximum number of partitions per RAM disk");
-module_param(part_show, int, S_IRUGO);
-MODULE_PARM_DESC(part_show, "Control RAM disk visibility in /proc/partitions");
+MODULE_PARM_DESC(max_part, "Num Minors to reserve between devices");
+
MODULE_LICENSE("GPL");
MODULE_ALIAS_BLOCKDEV_MAJOR(RAMDISK_MAJOR);
MODULE_ALIAS("rd");
brd->brd_queue = blk_alloc_queue(GFP_KERNEL);
if (!brd->brd_queue)
goto out_free_dev;
+
blk_queue_make_request(brd->brd_queue, brd_make_request);
blk_queue_max_hw_sectors(brd->brd_queue, 1024);
blk_queue_bounce_limit(brd->brd_queue, BLK_BOUNCE_ANY);
+ /* This is so fdisk will align partitions on 4k, because of
+ * direct_access API needing 4k alignment, returning a PFN
+ * (This is only a problem on very small devices <= 4M,
+ * otherwise fdisk will align on 1M. Regardless this call
+ * is harmless)
+ */
+ blk_queue_physical_block_size(brd->brd_queue, PAGE_SIZE);
+
brd->brd_queue->limits.discard_granularity = PAGE_SIZE;
brd->brd_queue->limits.max_discard_sectors = UINT_MAX;
brd->brd_queue->limits.discard_zeroes_data = 1;
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, brd->brd_queue);
- disk = brd->brd_disk = alloc_disk(1 << part_shift);
+ disk = brd->brd_disk = alloc_disk(max_part);
if (!disk)
goto out_free_queue;
disk->major = RAMDISK_MAJOR;
- disk->first_minor = i << part_shift;
+ disk->first_minor = i * max_part;
disk->fops = &brd_fops;
disk->private_data = brd;
disk->queue = brd->brd_queue;
- if (!part_show)
- disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
+ disk->flags = GENHD_FL_EXT_DEVT;
sprintf(disk->disk_name, "ram%d", i);
set_capacity(disk, rd_size * 2);
kfree(brd);
}
-static struct brd_device *brd_init_one(int i)
+static struct brd_device *brd_init_one(int i, bool *new)
{
struct brd_device *brd;
+ *new = false;
list_for_each_entry(brd, &brd_devices, brd_list) {
if (brd->brd_number == i)
goto out;
add_disk(brd->brd_disk);
list_add_tail(&brd->brd_list, &brd_devices);
}
+ *new = true;
out:
return brd;
}
{
struct brd_device *brd;
struct kobject *kobj;
+ bool new;
mutex_lock(&brd_devices_mutex);
- brd = brd_init_one(MINOR(dev) >> part_shift);
+ brd = brd_init_one(MINOR(dev) / max_part, &new);
kobj = brd ? get_disk(brd->brd_disk) : NULL;
mutex_unlock(&brd_devices_mutex);
- *part = 0;
+ if (new)
+ *part = 0;
+
return kobj;
}
static int __init brd_init(void)
{
- int i, nr;
- unsigned long range;
struct brd_device *brd, *next;
+ int i;
/*
* brd module now has a feature to instantiate underlying device
* structure on-demand, provided that there is an access dev node.
- * However, this will not work well with user space tool that doesn't
- * know about such "feature". In order to not break any existing
- * tool, we do the following:
*
- * (1) if rd_nr is specified, create that many upfront, and this
- * also becomes a hard limit.
- * (2) if rd_nr is not specified, create CONFIG_BLK_DEV_RAM_COUNT
- * (default 16) rd device on module load, user can further
- * extend brd device by create dev node themselves and have
- * kernel automatically instantiate actual device on-demand.
+ * (1) if rd_nr is specified, create that many upfront. else
+ * it defaults to CONFIG_BLK_DEV_RAM_COUNT
+ * (2) User can further extend brd devices by create dev node themselves
+ * and have kernel automatically instantiate actual device
+ * on-demand. Example:
+ * mknod /path/devnod_name b 1 X # 1 is the rd major
+ * fdisk -l /path/devnod_name
+ * If (X / max_part) was not already created it will be created
+ * dynamically.
*/
- part_shift = 0;
- if (max_part > 0) {
- part_shift = fls(max_part);
-
- /*
- * Adjust max_part according to part_shift as it is exported
- * to user space so that user can decide correct minor number
- * if [s]he want to create more devices.
- *
- * Note that -1 is required because partition 0 is reserved
- * for the whole disk.
- */
- max_part = (1UL << part_shift) - 1;
- }
-
- if ((1UL << part_shift) > DISK_MAX_PARTS)
- return -EINVAL;
-
- if (rd_nr > 1UL << (MINORBITS - part_shift))
- return -EINVAL;
-
- if (rd_nr) {
- nr = rd_nr;
- range = rd_nr << part_shift;
- } else {
- nr = CONFIG_BLK_DEV_RAM_COUNT;
- range = 1UL << MINORBITS;
- }
-
if (register_blkdev(RAMDISK_MAJOR, "ramdisk"))
return -EIO;
- for (i = 0; i < nr; i++) {
+ if (unlikely(!max_part))
+ max_part = 1;
+
+ for (i = 0; i < rd_nr; i++) {
brd = brd_alloc(i);
if (!brd)
goto out_free;
list_for_each_entry(brd, &brd_devices, brd_list)
add_disk(brd->brd_disk);
- blk_register_region(MKDEV(RAMDISK_MAJOR, 0), range,
+ blk_register_region(MKDEV(RAMDISK_MAJOR, 0), 1UL << MINORBITS,
THIS_MODULE, brd_probe, NULL, NULL);
- printk(KERN_INFO "brd: module loaded\n");
+ pr_info("brd: module loaded\n");
return 0;
out_free:
}
unregister_blkdev(RAMDISK_MAJOR, "ramdisk");
+ pr_info("brd: module NOT loaded !!!\n");
return -ENOMEM;
}
static void __exit brd_exit(void)
{
- unsigned long range;
struct brd_device *brd, *next;
- range = rd_nr ? rd_nr << part_shift : 1UL << MINORBITS;
-
list_for_each_entry_safe(brd, next, &brd_devices, brd_list)
brd_del_one(brd);
- blk_unregister_region(MKDEV(RAMDISK_MAJOR, 0), range);
+ blk_unregister_region(MKDEV(RAMDISK_MAJOR, 0), 1UL << MINORBITS);
unregister_blkdev(RAMDISK_MAJOR, "ramdisk");
+
+ pr_info("brd: module unloaded\n");
}
module_init(brd_init);
projects / cascardo / linux.git / blobdiff