#include <linux/loop.h>
#include <linux/compat.h>
#include <linux/suspend.h>
+#include <linux/freezer.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h> /* for invalidate_bdev() */
#include <linux/completion.h>
#include <linux/highmem.h>
#include <linux/gfp.h>
#include <linux/kthread.h>
+#include <linux/splice.h>
#include <asm/uaccess.h>
transfer_result = lo_do_transfer(lo, WRITE, page, offset,
bvec->bv_page, bv_offs, size, IV);
if (unlikely(transfer_result)) {
- char *kaddr;
-
/*
* The transfer failed, but we still write the data to
* keep prepare/commit calls balanced.
*/
printk(KERN_ERR "loop: transfer error block %llu\n",
(unsigned long long)index);
- kaddr = kmap_atomic(page, KM_USER0);
- memset(kaddr + offset, 0, size);
- kunmap_atomic(kaddr, KM_USER0);
+ zero_user_page(page, offset, size, KM_USER0);
}
flush_dcache_page(page);
ret = aops->commit_write(file, page, offset,
};
static int
-lo_read_actor(read_descriptor_t *desc, struct page *page,
- unsigned long offset, unsigned long size)
+lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
+ struct splice_desc *sd)
{
- unsigned long count = desc->count;
- struct lo_read_data *p = desc->arg.data;
+ struct lo_read_data *p = sd->u.data;
struct loop_device *lo = p->lo;
+ struct page *page = buf->page;
sector_t IV;
+ size_t size;
+ int ret;
- IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
+ ret = buf->ops->confirm(pipe, buf);
+ if (unlikely(ret))
+ return ret;
- if (size > count)
- size = count;
+ IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) +
+ (buf->offset >> 9);
+ size = sd->len;
+ if (size > p->bsize)
+ size = p->bsize;
- if (lo_do_transfer(lo, READ, page, offset, p->page, p->offset, size, IV)) {
- size = 0;
+ if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) {
printk(KERN_ERR "loop: transfer error block %ld\n",
page->index);
- desc->error = -EINVAL;
+ size = -EINVAL;
}
flush_dcache_page(p->page);
- desc->count = count - size;
- desc->written += size;
- p->offset += size;
+ if (size > 0)
+ p->offset += size;
+
return size;
}
static int
+lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd)
+{
+ return __splice_from_pipe(pipe, sd, lo_splice_actor);
+}
+
+static int
do_lo_receive(struct loop_device *lo,
struct bio_vec *bvec, int bsize, loff_t pos)
{
struct lo_read_data cookie;
+ struct splice_desc sd;
struct file *file;
- int retval;
+ long retval;
cookie.lo = lo;
cookie.page = bvec->bv_page;
cookie.offset = bvec->bv_offset;
cookie.bsize = bsize;
+
+ sd.len = 0;
+ sd.total_len = bvec->bv_len;
+ sd.flags = 0;
+ sd.pos = pos;
+ sd.u.data = &cookie;
+
file = lo->lo_backing_file;
- retval = file->f_op->sendfile(file, &pos, bvec->bv_len,
- lo_read_actor, &cookie);
- return (retval < 0)? retval: 0;
+ retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor);
+
+ if (retval < 0)
+ return retval;
+
+ return 0;
}
static int
struct loop_device *lo = data;
struct bio *bio;
- /*
- * loop can be used in an encrypted device,
- * hence, it mustn't be stopped at all
- * because it could be indirectly used during suspension
- */
- current->flags |= PF_NOFREEZE;
-
set_user_nice(current, -20);
while (!kthread_should_stop() || lo->lo_bio) {
if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
goto out_putf;
- /* new backing store needs to support loop (eg sendfile) */
- if (!inode->i_fop->sendfile)
+ /* new backing store needs to support loop (eg splice_read) */
+ if (!inode->i_fop->splice_read)
goto out_putf;
/* size of the new backing store needs to be the same */
* If we can't read - sorry. If we only can't write - well,
* it's going to be read-only.
*/
- if (!file->f_op->sendfile)
+ if (!file->f_op->splice_read)
goto out_putf;
if (aops->prepare_write && aops->commit_write)
lo_flags |= LO_FLAGS_USE_AOPS;
}
#endif
-static struct loop_device *loop_find_dev(int number)
-{
- struct loop_device *lo;
-
- list_for_each_entry(lo, &loop_devices, lo_list) {
- if (lo->lo_number == number)
- return lo;
- }
- return NULL;
-}
-
-static struct loop_device *loop_init_one(int i);
static int lo_open(struct inode *inode, struct file *file)
{
struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
lo->lo_refcnt++;
mutex_unlock(&lo->lo_ctl_mutex);
- mutex_lock(&loop_devices_mutex);
- if (!loop_find_dev(lo->lo_number + 1))
- loop_init_one(lo->lo_number + 1);
- mutex_unlock(&loop_devices_mutex);
-
return 0;
}
*/
static int max_loop;
module_param(max_loop, int, 0);
-MODULE_PARM_DESC(max_loop, "obsolete, loop device is created on-demand");
+MODULE_PARM_DESC(max_loop, "Maximum number of loop devices");
MODULE_LICENSE("GPL");
MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
EXPORT_SYMBOL(loop_register_transfer);
EXPORT_SYMBOL(loop_unregister_transfer);
-static struct loop_device *loop_init_one(int i)
+static struct loop_device *loop_alloc(int i)
{
struct loop_device *lo;
struct gendisk *disk;
disk->private_data = lo;
disk->queue = lo->lo_queue;
sprintf(disk->disk_name, "loop%d", i);
- add_disk(disk);
- list_add_tail(&lo->lo_list, &loop_devices);
return lo;
out_free_queue:
out_free_dev:
kfree(lo);
out:
- return ERR_PTR(-ENOMEM);
+ return NULL;
}
-static void loop_del_one(struct loop_device *lo)
+static void loop_free(struct loop_device *lo)
{
- del_gendisk(lo->lo_disk);
blk_cleanup_queue(lo->lo_queue);
put_disk(lo->lo_disk);
list_del(&lo->lo_list);
kfree(lo);
}
+static struct loop_device *loop_init_one(int i)
+{
+ struct loop_device *lo;
+
+ list_for_each_entry(lo, &loop_devices, lo_list) {
+ if (lo->lo_number == i)
+ return lo;
+ }
+
+ lo = loop_alloc(i);
+ if (lo) {
+ add_disk(lo->lo_disk);
+ list_add_tail(&lo->lo_list, &loop_devices);
+ }
+ return lo;
+}
+
+static void loop_del_one(struct loop_device *lo)
+{
+ del_gendisk(lo->lo_disk);
+ loop_free(lo);
+}
+
static struct kobject *loop_probe(dev_t dev, int *part, void *data)
{
- unsigned int number = dev & MINORMASK;
struct loop_device *lo;
+ struct kobject *kobj;
mutex_lock(&loop_devices_mutex);
- lo = loop_find_dev(number);
- if (lo == NULL)
- lo = loop_init_one(number);
+ lo = loop_init_one(dev & MINORMASK);
+ kobj = lo ? get_disk(lo->lo_disk) : ERR_PTR(-ENOMEM);
mutex_unlock(&loop_devices_mutex);
*part = 0;
- if (IS_ERR(lo))
- return (void *)lo;
- else
- return &lo->lo_disk->kobj;
+ return kobj;
}
static int __init loop_init(void)
{
- struct loop_device *lo;
+ int i, nr;
+ unsigned long range;
+ struct loop_device *lo, *next;
+
+ /*
+ * loop 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 max_loop is specified, create that many upfront, and this
+ * also becomes a hard limit.
+ * (2) if max_loop is not specified, create 8 loop device on module
+ * load, user can further extend loop device by create dev node
+ * themselves and have kernel automatically instantiate actual
+ * device on-demand.
+ */
+ if (max_loop > 1UL << MINORBITS)
+ return -EINVAL;
+
+ if (max_loop) {
+ nr = max_loop;
+ range = max_loop;
+ } else {
+ nr = 8;
+ range = 1UL << MINORBITS;
+ }
if (register_blkdev(LOOP_MAJOR, "loop"))
return -EIO;
- blk_register_region(MKDEV(LOOP_MAJOR, 0), 1UL << MINORBITS,
- THIS_MODULE, loop_probe, NULL, NULL);
- lo = loop_init_one(0);
- if (IS_ERR(lo))
- goto out;
+ for (i = 0; i < nr; i++) {
+ lo = loop_alloc(i);
+ if (!lo)
+ goto Enomem;
+ list_add_tail(&lo->lo_list, &loop_devices);
+ }
- if (max_loop) {
- printk(KERN_INFO "loop: the max_loop option is obsolete "
- "and will be removed in March 2008\n");
+ /* point of no return */
+
+ list_for_each_entry(lo, &loop_devices, lo_list)
+ add_disk(lo->lo_disk);
+
+ blk_register_region(MKDEV(LOOP_MAJOR, 0), range,
+ THIS_MODULE, loop_probe, NULL, NULL);
- }
printk(KERN_INFO "loop: module loaded\n");
return 0;
-out:
+Enomem:
+ printk(KERN_INFO "loop: out of memory\n");
+
+ list_for_each_entry_safe(lo, next, &loop_devices, lo_list)
+ loop_free(lo);
+
unregister_blkdev(LOOP_MAJOR, "loop");
- printk(KERN_ERR "loop: ran out of memory\n");
return -ENOMEM;
}
static void __exit loop_exit(void)
{
+ unsigned long range;
struct loop_device *lo, *next;
+ range = max_loop ? max_loop : 1UL << MINORBITS;
+
list_for_each_entry_safe(lo, next, &loop_devices, lo_list)
loop_del_one(lo);
- blk_unregister_region(MKDEV(LOOP_MAJOR, 0), 1UL << MINORBITS);
+ blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range);
if (unregister_blkdev(LOOP_MAJOR, "loop"))
printk(KERN_WARNING "loop: cannot unregister blkdev\n");
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff