3 files changed, 126 insertions, 17 deletions

diff --git a/block/Makefile b/block/Makefile
index 959feeb253be..3cfe7cebaa6a 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_IOSCHED_DEADLINE)	+= deadline-iosched.o
 obj-$(CONFIG_IOSCHED_CFQ)       += cfq-iosched.o
 
 obj-$(CONFIG_BLK_DEV_IO_TRACE)  += blktrace.o
+obj-$(CONFIG_COMPAT)            += compat_ioctl.o
diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
new file mode 100644
index 000000000000..d20fdb436f68
--- /dev/null
+++ b/block/compat_ioctl.c
@@ -0,0 +1,121 @@
+#include <linux/blkdev.h>
+#include <linux/blkpg.h>
+#include <linux/blktrace_api.h>
+#include <linux/cdrom.h>
+#include <linux/compat.h>
+#include <linux/elevator.h>
+#include <linux/fd.h>
+#include <linux/hdreg.h>
+#include <linux/syscalls.h>
+#include <linux/smp_lock.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+static int compat_put_ushort(unsigned long arg, unsigned short val)
+{
+        return put_user(val, (unsigned short __user *)compat_ptr(arg));
+}
+
+static int compat_put_int(unsigned long arg, int val)
+{
+        return put_user(val, (compat_int_t __user *)compat_ptr(arg));
+}
+
+static int compat_put_long(unsigned long arg, long val)
+{
+        return put_user(val, (compat_long_t __user *)compat_ptr(arg));
+}
+
+static int compat_put_ulong(unsigned long arg, compat_ulong_t val)
+{
+        return put_user(val, (compat_ulong_t __user *)compat_ptr(arg));
+}
+
+static int compat_put_u64(unsigned long arg, u64 val)
+{
+        return put_user(val, (compat_u64 __user *)compat_ptr(arg));
+}
+
+#define BLKBSZGET_32            _IOR(0x12, 112, int)
+#define BLKBSZSET_32            _IOW(0x12, 113, int)
+#define BLKGETSIZE64_32         _IOR(0x12, 114, int)
+
+static int compat_blkdev_locked_ioctl(struct inode *inode, struct file *file,
+                                struct block_device *bdev,
+                                unsigned cmd, unsigned long arg)
+{
+        struct backing_dev_info *bdi;
+
+        switch (cmd) {
+        case BLKRAGET:
+        case BLKFRAGET:
+                if (!arg)
+                        return -EINVAL;
+                bdi = blk_get_backing_dev_info(bdev);
+                if (bdi == NULL)
+                        return -ENOTTY;
+                return compat_put_long(arg,
+                                       (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
+        case BLKROGET: /* compatible */
+                return compat_put_int(arg, bdev_read_only(bdev) != 0);
+        case BLKBSZGET_32: /* get the logical block size (cf. BLKSSZGET) */
+                return compat_put_int(arg, block_size(bdev));
+        case BLKSSZGET: /* get block device hardware sector size */
+                return compat_put_int(arg, bdev_hardsect_size(bdev));
+        case BLKSECTGET:
+                return compat_put_ushort(arg,
+                                         bdev_get_queue(bdev)->max_sectors);
+        case BLKRASET: /* compatible, but no compat_ptr (!) */
+        case BLKFRASET:
+                if (!capable(CAP_SYS_ADMIN))
+                        return -EACCES;
+                bdi = blk_get_backing_dev_info(bdev);
+                if (bdi == NULL)
+                        return -ENOTTY;
+                bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
+                return 0;
+        case BLKGETSIZE:
+                if ((bdev->bd_inode->i_size >> 9) > ~0UL)
+                        return -EFBIG;
+                return compat_put_ulong(arg, bdev->bd_inode->i_size >> 9);
+
+        case BLKGETSIZE64_32:
+                return compat_put_u64(arg, bdev->bd_inode->i_size);
+        }
+        return -ENOIOCTLCMD;
+}
+
+/* Most of the generic ioctls are handled in the normal fallback path.
+   This assumes the blkdev's low level compat_ioctl always returns
+   ENOIOCTLCMD for unknown ioctls. */
+long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
+{
+        int ret = -ENOIOCTLCMD;
+        struct inode *inode = file->f_mapping->host;
+        struct block_device *bdev = inode->i_bdev;
+        struct gendisk *disk = bdev->bd_disk;
+
+        switch (cmd) {
+        case BLKFLSBUF:
+        case BLKROSET:
+        /*
+         * the ones below are implemented in blkdev_locked_ioctl,
+         * but we call blkdev_ioctl, which gets the lock for us
+         */
+        case BLKRRPART:
+                return blkdev_ioctl(inode, file, cmd,
+                                (unsigned long)compat_ptr(arg));
+        case BLKBSZSET_32:
+                return blkdev_ioctl(inode, file, BLKBSZSET,
+                                (unsigned long)compat_ptr(arg));
+        }
+
+        lock_kernel();
+        ret = compat_blkdev_locked_ioctl(inode, file, bdev, cmd, arg);
+        /* FIXME: why do we assume -> compat_ioctl needs the BKL? */
+        if (ret == -ENOIOCTLCMD && disk->fops->compat_ioctl)
+                ret = disk->fops->compat_ioctl(file, cmd, arg);
+        unlock_kernel();
+
+        return ret;
+}
diff --git a/block/ioctl.c b/block/ioctl.c
index f7e3e8abf887..52d6385216ad 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -217,6 +217,10 @@ int blkdev_driver_ioctl(struct inode *inode, struct file *file,
 }
 EXPORT_SYMBOL_GPL(blkdev_driver_ioctl);
 
+/*
+ * always keep this in sync with compat_blkdev_ioctl() and
+ * compat_blkdev_locked_ioctl()
+ */
 int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,
                         unsigned long arg)
 {
@@ -284,21 +288,4 @@ int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,
 
         return blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 }
-
-/* Most of the generic ioctls are handled in the normal fallback path.
-   This assumes the blkdev's low level compat_ioctl always returns
-   ENOIOCTLCMD for unknown ioctls. */
-long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
-{
-        struct block_device *bdev = file->f_path.dentry->d_inode->i_bdev;
-        struct gendisk *disk = bdev->bd_disk;
-        int ret = -ENOIOCTLCMD;
-        if (disk->fops->compat_ioctl) {
-                lock_kernel();
-                ret = disk->fops->compat_ioctl(file, cmd, arg);
-                unlock_kernel();
-        }
-        return ret;
-}
-
 EXPORT_SYMBOL_GPL(blkdev_ioctl);