From f58c4c0a17e500e767473598b3deafaa1d64051d Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Tue, 9 Oct 2007 13:23:51 +0200
Subject: compat_ioctl: move common block ioctls to compat_blkdev_ioctl

Make compat_blkdev_ioctl and blkdev_ioctl reflect the respective
native versions. This is somewhat more efficient and makes it easier
to keep the two in sync.

Also get rid of the bogus handling for broken_blkgetsize and the
duplicate entry for BLKRASET.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
 block/compat_ioctl.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 block/compat_ioctl.c

(limited to 'block/compat_ioctl.c')

diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
new file mode 100644
index 00000000000..d20fdb436f6
--- /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;
+}
-- 
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