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path: root/drivers/block/loop.c
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Diffstat (limited to 'drivers/block/loop.c')
-rw-r--r--drivers/block/loop.c240
1 files changed, 194 insertions, 46 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c774121684d..d6bb8da955a 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -66,12 +66,14 @@
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/loop.h>
+#include <linux/compat.h>
#include <linux/suspend.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 <asm/uaccess.h>
@@ -522,15 +524,12 @@ static int loop_make_request(request_queue_t *q, struct bio *old_bio)
goto out;
if (unlikely(rw == WRITE && (lo->lo_flags & LO_FLAGS_READ_ONLY)))
goto out;
- lo->lo_pending++;
loop_add_bio(lo, old_bio);
+ wake_up(&lo->lo_event);
spin_unlock_irq(&lo->lo_lock);
- complete(&lo->lo_bh_done);
return 0;
out:
- if (lo->lo_pending == 0)
- complete(&lo->lo_bh_done);
spin_unlock_irq(&lo->lo_lock);
bio_io_error(old_bio, old_bio->bi_size);
return 0;
@@ -570,14 +569,18 @@ static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio)
* to avoid blocking in our make_request_fn. it also does loop decrypting
* on reads for block backed loop, as that is too heavy to do from
* b_end_io context where irqs may be disabled.
+ *
+ * Loop explanation: loop_clr_fd() sets lo_state to Lo_rundown before
+ * calling kthread_stop(). Therefore once kthread_should_stop() is
+ * true, make_request will not place any more requests. Therefore
+ * once kthread_should_stop() is true and lo_bio is NULL, we are
+ * done with the loop.
*/
static int loop_thread(void *data)
{
struct loop_device *lo = data;
struct bio *bio;
- daemonize("loop%d", lo->lo_number);
-
/*
* loop can be used in an encrypted device,
* hence, it mustn't be stopped at all
@@ -587,47 +590,21 @@ static int loop_thread(void *data)
set_user_nice(current, -20);
- lo->lo_state = Lo_bound;
- lo->lo_pending = 1;
+ while (!kthread_should_stop() || lo->lo_bio) {
- /*
- * complete it, we are running
- */
- complete(&lo->lo_done);
-
- for (;;) {
- int pending;
+ wait_event_interruptible(lo->lo_event,
+ lo->lo_bio || kthread_should_stop());
- if (wait_for_completion_interruptible(&lo->lo_bh_done))
+ if (!lo->lo_bio)
continue;
-
spin_lock_irq(&lo->lo_lock);
-
- /*
- * could be completed because of tear-down, not pending work
- */
- if (unlikely(!lo->lo_pending)) {
- spin_unlock_irq(&lo->lo_lock);
- break;
- }
-
bio = loop_get_bio(lo);
- lo->lo_pending--;
- pending = lo->lo_pending;
spin_unlock_irq(&lo->lo_lock);
BUG_ON(!bio);
loop_handle_bio(lo, bio);
-
- /*
- * upped both for pending work and tear-down, lo_pending
- * will hit zero then
- */
- if (unlikely(!pending))
- break;
}
- complete(&lo->lo_done);
return 0;
}
@@ -840,12 +817,26 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
set_blocksize(bdev, lo_blocksize);
- error = kernel_thread(loop_thread, lo, CLONE_KERNEL);
- if (error < 0)
- goto out_putf;
- wait_for_completion(&lo->lo_done);
+ lo->lo_thread = kthread_create(loop_thread, lo, "loop%d",
+ lo->lo_number);
+ if (IS_ERR(lo->lo_thread)) {
+ error = PTR_ERR(lo->lo_thread);
+ goto out_clr;
+ }
+ lo->lo_state = Lo_bound;
+ wake_up_process(lo->lo_thread);
return 0;
+out_clr:
+ lo->lo_thread = NULL;
+ lo->lo_device = NULL;
+ lo->lo_backing_file = NULL;
+ lo->lo_flags = 0;
+ set_capacity(disks[lo->lo_number], 0);
+ invalidate_bdev(bdev, 0);
+ bd_set_size(bdev, 0);
+ mapping_set_gfp_mask(mapping, lo->old_gfp_mask);
+ lo->lo_state = Lo_unbound;
out_putf:
fput(file);
out:
@@ -907,12 +898,9 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
spin_lock_irq(&lo->lo_lock);
lo->lo_state = Lo_rundown;
- lo->lo_pending--;
- if (!lo->lo_pending)
- complete(&lo->lo_bh_done);
spin_unlock_irq(&lo->lo_lock);
- wait_for_completion(&lo->lo_done);
+ kthread_stop(lo->lo_thread);
lo->lo_backing_file = NULL;
@@ -925,6 +913,7 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
lo->lo_sizelimit = 0;
lo->lo_encrypt_key_size = 0;
lo->lo_flags = 0;
+ lo->lo_thread = NULL;
memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
memset(lo->lo_file_name, 0, LO_NAME_SIZE);
@@ -1177,6 +1166,162 @@ static int lo_ioctl(struct inode * inode, struct file * file,
return err;
}
+#ifdef CONFIG_COMPAT
+struct compat_loop_info {
+ compat_int_t lo_number; /* ioctl r/o */
+ compat_dev_t lo_device; /* ioctl r/o */
+ compat_ulong_t lo_inode; /* ioctl r/o */
+ compat_dev_t lo_rdevice; /* ioctl r/o */
+ compat_int_t lo_offset;
+ compat_int_t lo_encrypt_type;
+ compat_int_t lo_encrypt_key_size; /* ioctl w/o */
+ compat_int_t lo_flags; /* ioctl r/o */
+ char lo_name[LO_NAME_SIZE];
+ unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
+ compat_ulong_t lo_init[2];
+ char reserved[4];
+};
+
+/*
+ * Transfer 32-bit compatibility structure in userspace to 64-bit loop info
+ * - noinlined to reduce stack space usage in main part of driver
+ */
+static noinline int
+loop_info64_from_compat(const struct compat_loop_info *arg,
+ struct loop_info64 *info64)
+{
+ struct compat_loop_info info;
+
+ if (copy_from_user(&info, arg, sizeof(info)))
+ return -EFAULT;
+
+ memset(info64, 0, sizeof(*info64));
+ info64->lo_number = info.lo_number;
+ info64->lo_device = info.lo_device;
+ info64->lo_inode = info.lo_inode;
+ info64->lo_rdevice = info.lo_rdevice;
+ info64->lo_offset = info.lo_offset;
+ info64->lo_sizelimit = 0;
+ info64->lo_encrypt_type = info.lo_encrypt_type;
+ info64->lo_encrypt_key_size = info.lo_encrypt_key_size;
+ info64->lo_flags = info.lo_flags;
+ info64->lo_init[0] = info.lo_init[0];
+ info64->lo_init[1] = info.lo_init[1];
+ if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
+ memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE);
+ else
+ memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE);
+ memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE);
+ return 0;
+}
+
+/*
+ * Transfer 64-bit loop info to 32-bit compatibility structure in userspace
+ * - noinlined to reduce stack space usage in main part of driver
+ */
+static noinline int
+loop_info64_to_compat(const struct loop_info64 *info64,
+ struct compat_loop_info __user *arg)
+{
+ struct compat_loop_info info;
+
+ memset(&info, 0, sizeof(info));
+ info.lo_number = info64->lo_number;
+ info.lo_device = info64->lo_device;
+ info.lo_inode = info64->lo_inode;
+ info.lo_rdevice = info64->lo_rdevice;
+ info.lo_offset = info64->lo_offset;
+ info.lo_encrypt_type = info64->lo_encrypt_type;
+ info.lo_encrypt_key_size = info64->lo_encrypt_key_size;
+ info.lo_flags = info64->lo_flags;
+ info.lo_init[0] = info64->lo_init[0];
+ info.lo_init[1] = info64->lo_init[1];
+ if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
+ memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
+ else
+ memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE);
+ memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
+
+ /* error in case values were truncated */
+ if (info.lo_device != info64->lo_device ||
+ info.lo_rdevice != info64->lo_rdevice ||
+ info.lo_inode != info64->lo_inode ||
+ info.lo_offset != info64->lo_offset ||
+ info.lo_init[0] != info64->lo_init[0] ||
+ info.lo_init[1] != info64->lo_init[1])
+ return -EOVERFLOW;
+
+ if (copy_to_user(arg, &info, sizeof(info)))
+ return -EFAULT;
+ return 0;
+}
+
+static int
+loop_set_status_compat(struct loop_device *lo,
+ const struct compat_loop_info __user *arg)
+{
+ struct loop_info64 info64;
+ int ret;
+
+ ret = loop_info64_from_compat(arg, &info64);
+ if (ret < 0)
+ return ret;
+ return loop_set_status(lo, &info64);
+}
+
+static int
+loop_get_status_compat(struct loop_device *lo,
+ struct compat_loop_info __user *arg)
+{
+ struct loop_info64 info64;
+ int err = 0;
+
+ if (!arg)
+ err = -EINVAL;
+ if (!err)
+ err = loop_get_status(lo, &info64);
+ if (!err)
+ err = loop_info64_to_compat(&info64, arg);
+ return err;
+}
+
+static long lo_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
+ int err;
+
+ lock_kernel();
+ switch(cmd) {
+ case LOOP_SET_STATUS:
+ mutex_lock(&lo->lo_ctl_mutex);
+ err = loop_set_status_compat(
+ lo, (const struct compat_loop_info __user *) arg);
+ mutex_unlock(&lo->lo_ctl_mutex);
+ break;
+ case LOOP_GET_STATUS:
+ mutex_lock(&lo->lo_ctl_mutex);
+ err = loop_get_status_compat(
+ lo, (struct compat_loop_info __user *) arg);
+ mutex_unlock(&lo->lo_ctl_mutex);
+ break;
+ case LOOP_CLR_FD:
+ case LOOP_GET_STATUS64:
+ case LOOP_SET_STATUS64:
+ arg = (unsigned long) compat_ptr(arg);
+ case LOOP_SET_FD:
+ case LOOP_CHANGE_FD:
+ err = lo_ioctl(inode, file, cmd, arg);
+ break;
+ default:
+ err = -ENOIOCTLCMD;
+ break;
+ }
+ unlock_kernel();
+ return err;
+}
+#endif
+
static int lo_open(struct inode *inode, struct file *file)
{
struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
@@ -1204,6 +1349,9 @@ static struct block_device_operations lo_fops = {
.open = lo_open,
.release = lo_release,
.ioctl = lo_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = lo_compat_ioctl,
+#endif
};
/*
@@ -1287,9 +1435,9 @@ static int __init loop_init(void)
if (!lo->lo_queue)
goto out_mem4;
mutex_init(&lo->lo_ctl_mutex);
- init_completion(&lo->lo_done);
- init_completion(&lo->lo_bh_done);
lo->lo_number = i;
+ lo->lo_thread = NULL;
+ init_waitqueue_head(&lo->lo_event);
spin_lock_init(&lo->lo_lock);
disk->major = LOOP_MAJOR;
disk->first_minor = i;