#include <linux/vmalloc.h>
#include <linux/err.h>
#include <linux/idr.h>
+#include <linux/sysfs.h>
#include "zram_drv.h"
static DEFINE_IDR(zram_index_idr);
+/* idr index must be protected */
+static DEFINE_MUTEX(zram_index_mutex);
+
static int zram_major;
static const char *default_compressor = "lzo";
struct device_attribute *attr, const char *buf, size_t len)
{
struct zram *zram = dev_to_zram(dev);
+ size_t sz;
+
down_write(&zram->init_lock);
if (init_done(zram)) {
up_write(&zram->init_lock);
return -EBUSY;
}
strlcpy(zram->compressor, buf, sizeof(zram->compressor));
+
+ /* ignore trailing newline */
+ sz = strlen(zram->compressor);
+ if (sz > 0 && zram->compressor[sz - 1] == '\n')
+ zram->compressor[sz - 1] = 0x00;
+
+ if (!zcomp_available_algorithm(zram->compressor))
+ len = -EINVAL;
+
up_write(&zram->init_lock);
return len;
}
kfree(meta);
}
-static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize)
+static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize)
{
size_t num_pages;
- char pool_name[8];
struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
if (!meta)
goto out_error;
}
- snprintf(pool_name, sizeof(pool_name), "zram%d", device_id);
meta->mem_pool = zs_create_pool(pool_name, GFP_NOIO | __GFP_HIGHMEM);
if (!meta->mem_pool) {
pr_err("Error creating memory pool\n");
struct page *page;
unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
struct zram_meta *meta = zram->meta;
- struct zcomp_strm *zstrm;
- bool locked = false;
+ struct zcomp_strm *zstrm = NULL;
unsigned long alloced_pages;
page = bvec->bv_page;
}
zstrm = zcomp_strm_find(zram->comp);
- locked = true;
user_mem = kmap_atomic(page);
if (is_partial_io(bvec)) {
}
zcomp_strm_release(zram->comp, zstrm);
- locked = false;
+ zstrm = NULL;
zs_unmap_object(meta->mem_pool, handle);
/*
atomic64_add(clen, &zram->stats.compr_data_size);
atomic64_inc(&zram->stats.pages_stored);
out:
- if (locked)
+ if (zstrm)
zcomp_strm_release(zram->comp, zstrm);
if (is_partial_io(bvec))
kfree(uncmem);
return -EINVAL;
disksize = PAGE_ALIGN(disksize);
- meta = zram_meta_alloc(zram->disk->first_minor, disksize);
+ meta = zram_meta_alloc(zram->disk->disk_name, disksize);
if (!meta)
return -ENOMEM;
struct zram *zram;
struct block_device *bdev;
+ ret = kstrtou16(buf, 10, &do_reset);
+ if (ret)
+ return ret;
+
+ if (!do_reset)
+ return -EINVAL;
+
zram = dev_to_zram(dev);
bdev = bdget_disk(zram->disk, 0);
-
if (!bdev)
return -ENOMEM;
mutex_lock(&bdev->bd_mutex);
- /* Do not reset an active device! */
- if (bdev->bd_openers) {
- ret = -EBUSY;
- goto out;
+ /* Do not reset an active device or claimed device */
+ if (bdev->bd_openers || zram->claim) {
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdev);
+ return -EBUSY;
}
- ret = kstrtou16(buf, 10, &do_reset);
- if (ret)
- goto out;
-
- if (!do_reset) {
- ret = -EINVAL;
- goto out;
- }
+ /* From now on, anyone can't open /dev/zram[0-9] */
+ zram->claim = true;
+ mutex_unlock(&bdev->bd_mutex);
- /* Make sure all pending I/O is finished */
+ /* Make sure all the pending I/O are finished */
fsync_bdev(bdev);
zram_reset_device(zram);
-
- mutex_unlock(&bdev->bd_mutex);
revalidate_disk(zram->disk);
bdput(bdev);
+ mutex_lock(&bdev->bd_mutex);
+ zram->claim = false;
+ mutex_unlock(&bdev->bd_mutex);
+
return len;
+}
+
+static int zram_open(struct block_device *bdev, fmode_t mode)
+{
+ int ret = 0;
+ struct zram *zram;
+
+ WARN_ON(!mutex_is_locked(&bdev->bd_mutex));
+
+ zram = bdev->bd_disk->private_data;
+ /* zram was claimed to reset so open request fails */
+ if (zram->claim)
+ ret = -EBUSY;
-out:
- mutex_unlock(&bdev->bd_mutex);
- bdput(bdev);
return ret;
}
static const struct block_device_operations zram_devops = {
+ .open = zram_open,
.swap_slot_free_notify = zram_slot_free_notify,
.rw_page = zram_rw_page,
.owner = THIS_MODULE
.attrs = zram_disk_attrs,
};
-static int zram_add(int device_id)
+/*
+ * Allocate and initialize new zram device. the function returns
+ * '>= 0' device_id upon success, and negative value otherwise.
+ */
+static int zram_add(void)
{
struct zram *zram;
struct request_queue *queue;
- int ret;
+ int ret, device_id;
zram = kzalloc(sizeof(struct zram), GFP_KERNEL);
if (!zram)
return -ENOMEM;
- ret = idr_alloc(&zram_index_idr, zram, device_id,
- device_id + 1, GFP_KERNEL);
+ ret = idr_alloc(&zram_index_idr, zram, 0, 0, GFP_KERNEL);
if (ret < 0)
goto out_free_dev;
+ device_id = ret;
init_rwsem(&zram->init_lock);
zram->max_comp_streams = 1;
pr_info("Added device: %s\n", zram->disk->disk_name);
- return 0;
+ return device_id;
out_free_disk:
del_gendisk(zram->disk);
return ret;
}
-static void zram_remove(struct zram *zram)
+static int zram_remove(struct zram *zram)
{
- pr_info("Removed device: %s\n", zram->disk->disk_name);
+ struct block_device *bdev;
+
+ bdev = bdget_disk(zram->disk, 0);
+ if (!bdev)
+ return -ENOMEM;
+
+ mutex_lock(&bdev->bd_mutex);
+ if (bdev->bd_openers || zram->claim) {
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdev);
+ return -EBUSY;
+ }
+
+ zram->claim = true;
+ mutex_unlock(&bdev->bd_mutex);
+
/*
* Remove sysfs first, so no one will perform a disksize
- * store while we destroy the devices
+ * store while we destroy the devices. This also helps during
+ * hot_remove -- zram_reset_device() is the last holder of
+ * ->init_lock, no later/concurrent disksize_store() or any
+ * other sysfs handlers are possible.
*/
sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,
&zram_disk_attr_group);
+ /* Make sure all the pending I/O are finished */
+ fsync_bdev(bdev);
zram_reset_device(zram);
+ bdput(bdev);
+
+ pr_info("Removed device: %s\n", zram->disk->disk_name);
+
idr_remove(&zram_index_idr, zram->disk->first_minor);
blk_cleanup_queue(zram->disk->queue);
del_gendisk(zram->disk);
put_disk(zram->disk);
kfree(zram);
+ return 0;
+}
+
+/* zram-control sysfs attributes */
+static ssize_t hot_add_show(struct class *class,
+ struct class_attribute *attr,
+ char *buf)
+{
+ int ret;
+
+ mutex_lock(&zram_index_mutex);
+ ret = zram_add();
+ mutex_unlock(&zram_index_mutex);
+
+ if (ret < 0)
+ return ret;
+ return scnprintf(buf, PAGE_SIZE, "%d\n", ret);
}
+static ssize_t hot_remove_store(struct class *class,
+ struct class_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ struct zram *zram;
+ int ret, dev_id;
+
+ /* dev_id is gendisk->first_minor, which is `int' */
+ ret = kstrtoint(buf, 10, &dev_id);
+ if (ret)
+ return ret;
+ if (dev_id < 0)
+ return -EINVAL;
+
+ mutex_lock(&zram_index_mutex);
+
+ zram = idr_find(&zram_index_idr, dev_id);
+ if (zram)
+ ret = zram_remove(zram);
+ else
+ ret = -ENODEV;
+
+ mutex_unlock(&zram_index_mutex);
+ return ret ? ret : count;
+}
+
+static struct class_attribute zram_control_class_attrs[] = {
+ __ATTR_RO(hot_add),
+ __ATTR_WO(hot_remove),
+ __ATTR_NULL,
+};
+
+static struct class zram_control_class = {
+ .name = "zram-control",
+ .owner = THIS_MODULE,
+ .class_attrs = zram_control_class_attrs,
+};
+
static int zram_remove_cb(int id, void *ptr, void *data)
{
zram_remove(ptr);
static void destroy_devices(void)
{
+ class_unregister(&zram_control_class);
idr_for_each(&zram_index_idr, &zram_remove_cb, NULL);
idr_destroy(&zram_index_idr);
unregister_blkdev(zram_major, "zram");
static int __init zram_init(void)
{
- int ret, dev_id;
+ int ret;
+
+ ret = class_register(&zram_control_class);
+ if (ret) {
+ pr_warn("Unable to register zram-control class\n");
+ return ret;
+ }
zram_major = register_blkdev(0, "zram");
if (zram_major <= 0) {
pr_warn("Unable to get major number\n");
+ class_unregister(&zram_control_class);
return -EBUSY;
}
- for (dev_id = 0; dev_id < num_devices; dev_id++) {
- ret = zram_add(dev_id);
- if (ret != 0)
+ while (num_devices != 0) {
+ mutex_lock(&zram_index_mutex);
+ ret = zram_add();
+ mutex_unlock(&zram_index_mutex);
+ if (ret < 0)
goto out_error;
+ num_devices--;
}
return 0;
projects / linux-beck.git / blobdiff