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53bb724f94
After a bit of poking around wondering why my 32-bit user-space can't seem to send a proper ioctl(BLKPG) to an MTD on my 64-bit kernel (ARM64), I noticed that struct blkpg_ioctl_arg is actually pretty unsuitable for use in the ioctl() ABI, due to its use of raw pointers, and its lack of alignment/packing restrictions (32-bit arch'es tend to pack the 4 fields into 4 32-bit words, whereas 64-bit arch'es would add padding after the third int, and make this 6 32-bit words). Anyway, this means BLKPG deserves some special compat_ioctl handling. Do the conversion in a small shim for MTD. block/compat_ioctl.c already has compat support for the block subsystem, but it does so by a re-marshalling data to/from user-space (see compat_blkpg_ioctl()). Personally, I think this approach is cleaner. Tested only on MTD, with an ARM32 user space on an ARM64 kernel. Signed-off-by: Brian Norris <computersforpeace@gmail.com>
59 lines
1.6 KiB
C
59 lines
1.6 KiB
C
#ifndef _UAPI__LINUX_BLKPG_H
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#define _UAPI__LINUX_BLKPG_H
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/*
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* Partition table and disk geometry handling
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*
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* A single ioctl with lots of subfunctions:
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*
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* Device number stuff:
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* get_whole_disk() (given the device number of a partition,
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* find the device number of the encompassing disk)
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* get_all_partitions() (given the device number of a disk, return the
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* device numbers of all its known partitions)
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*
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* Partition stuff:
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* add_partition()
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* delete_partition()
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* test_partition_in_use() (also for test_disk_in_use)
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*
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* Geometry stuff:
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* get_geometry()
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* set_geometry()
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* get_bios_drivedata()
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*
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* For today, only the partition stuff - aeb, 990515
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*/
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#include <linux/compiler.h>
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#include <linux/ioctl.h>
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#define BLKPG _IO(0x12,105)
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/* The argument structure */
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struct blkpg_ioctl_arg {
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int op;
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int flags;
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int datalen;
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void __user *data;
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};
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/* The subfunctions (for the op field) */
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#define BLKPG_ADD_PARTITION 1
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#define BLKPG_DEL_PARTITION 2
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#define BLKPG_RESIZE_PARTITION 3
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/* Sizes of name fields. Unused at present. */
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#define BLKPG_DEVNAMELTH 64
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#define BLKPG_VOLNAMELTH 64
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/* The data structure for ADD_PARTITION and DEL_PARTITION */
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struct blkpg_partition {
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long long start; /* starting offset in bytes */
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long long length; /* length in bytes */
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int pno; /* partition number */
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char devname[BLKPG_DEVNAMELTH]; /* partition name, like sda5 or c0d1p2,
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to be used in kernel messages */
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char volname[BLKPG_VOLNAMELTH]; /* volume label */
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};
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#endif /* _UAPI__LINUX_BLKPG_H */
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