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  • Committer: Package Import Robot
  • Author(s): Alessio Igor Bogani
  • Date: 2011-10-26 11:13:05 UTC
  • Revision ID: package-import@ubuntu.com-20111026111305-tz023xykf0i6eosh
Tags: upstream-3.2.0
Import upstream version 3.2.0

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Documentation/magic-number.txt
 
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This file is a registry of magic numbers which are in use.  When you
 
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add a magic number to a structure, you should also add it to this
 
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file, since it is best if the magic numbers used by various structures
 
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are unique.
 
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It is a *very* good idea to protect kernel data structures with magic
 
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numbers.  This allows you to check at run time whether (a) a structure
 
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has been clobbered, or (b) you've passed the wrong structure to a
 
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routine.  This last is especially useful --- particularly when you are
 
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passing pointers to structures via a void * pointer.  The tty code,
 
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for example, does this frequently to pass driver-specific and line
 
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discipline-specific structures back and forth.
 
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The way to use magic numbers is to declare then at the beginning of
 
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the structure, like so:
 
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struct tty_ldisc {
 
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        int     magic;
 
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        ...
 
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};
 
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Please follow this discipline when you are adding future enhancements
 
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to the kernel!  It has saved me countless hours of debugging,
 
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especially in the screwy cases where an array has been overrun and
 
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structures following the array have been overwritten.  Using this
 
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discipline, these cases get detected quickly and safely.
 
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                                        Theodore Ts'o
 
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                                        31 Mar 94
 
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The magic table is current to Linux 2.1.55.
 
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                                        Michael Chastain
 
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                                        <mailto:mec@shout.net>
 
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                                        22 Sep 1997
 
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Now it should be up to date with Linux 2.1.112. Because
 
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we are in feature freeze time it is very unlikely that
 
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something will change before 2.2.x. The entries are
 
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sorted by number field.
 
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                                        Krzysztof G. Baranowski
 
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                                        <mailto: kgb@knm.org.pl>
 
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                                        29 Jul 1998
 
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Updated the magic table to Linux 2.5.45. Right over the feature freeze,
 
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but it is possible that some new magic numbers will sneak into the
 
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kernel before 2.6.x yet.
 
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                                        Petr Baudis
 
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                                        <pasky@ucw.cz>
 
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                                        03 Nov 2002
 
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Updated the magic table to Linux 2.5.74.
 
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                                        Fabian Frederick
 
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                                        <ffrederick@users.sourceforge.net>
 
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                                        09 Jul 2003
 
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Magic Name            Number      Structure            File
 
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===========================================================================
 
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PG_MAGIC              'P'         pg_{read,write}_hdr include/linux/pg.h
 
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CMAGIC                0x0111      user              include/linux/a.out.h
 
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MKISS_DRIVER_MAGIC    0x04bf      mkiss_channel     drivers/net/mkiss.h
 
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RISCOM8_MAGIC         0x0907      riscom_port       drivers/char/riscom8.h
 
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SPECIALIX_MAGIC       0x0907      specialix_port    drivers/char/specialix_io8.h
 
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HDLC_MAGIC            0x239e      n_hdlc            drivers/char/n_hdlc.c
 
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APM_BIOS_MAGIC        0x4101      apm_user          arch/x86/kernel/apm_32.c
 
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CYCLADES_MAGIC        0x4359      cyclades_port     include/linux/cyclades.h
 
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DB_MAGIC              0x4442      fc_info           drivers/net/iph5526_novram.c
 
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DL_MAGIC              0x444d      fc_info           drivers/net/iph5526_novram.c
 
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FASYNC_MAGIC          0x4601      fasync_struct     include/linux/fs.h
 
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FF_MAGIC              0x4646      fc_info           drivers/net/iph5526_novram.c
 
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ISICOM_MAGIC          0x4d54      isi_port          include/linux/isicom.h
 
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PTY_MAGIC             0x5001                        drivers/char/pty.c
 
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PPP_MAGIC             0x5002      ppp               include/linux/if_pppvar.h
 
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SERIAL_MAGIC          0x5301      async_struct      include/linux/serial.h
 
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SSTATE_MAGIC          0x5302      serial_state      include/linux/serial.h
 
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SLIP_MAGIC            0x5302      slip              drivers/net/slip.h
 
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STRIP_MAGIC           0x5303      strip             drivers/net/strip.c
 
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X25_ASY_MAGIC         0x5303      x25_asy           drivers/net/x25_asy.h
 
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SIXPACK_MAGIC         0x5304      sixpack           drivers/net/hamradio/6pack.h
 
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AX25_MAGIC            0x5316      ax_disp           drivers/net/mkiss.h
 
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ESP_MAGIC             0x53ee      esp_struct        drivers/char/esp.h
 
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TTY_MAGIC             0x5401      tty_struct        include/linux/tty.h
 
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MGSL_MAGIC            0x5401      mgsl_info         drivers/char/synclink.c
 
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TTY_DRIVER_MAGIC      0x5402      tty_driver        include/linux/tty_driver.h
 
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MGSLPC_MAGIC          0x5402      mgslpc_info       drivers/char/pcmcia/synclink_cs.c
 
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TTY_LDISC_MAGIC       0x5403      tty_ldisc         include/linux/tty_ldisc.h
 
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USB_SERIAL_MAGIC      0x6702      usb_serial        drivers/usb/serial/usb-serial.h
 
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FULL_DUPLEX_MAGIC     0x6969                        drivers/net/tulip/de2104x.c
 
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USB_BLUETOOTH_MAGIC   0x6d02      usb_bluetooth     drivers/usb/class/bluetty.c
 
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RFCOMM_TTY_MAGIC      0x6d02                        net/bluetooth/rfcomm/tty.c
 
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USB_SERIAL_PORT_MAGIC 0x7301      usb_serial_port   drivers/usb/serial/usb-serial.h
 
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CG_MAGIC              0x00090255  ufs_cylinder_group include/linux/ufs_fs.h
 
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A2232_MAGIC           0x000a2232  gs_port           drivers/char/ser_a2232.h
 
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RPORT_MAGIC           0x00525001  r_port            drivers/char/rocket_int.h
 
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LSEMAGIC              0x05091998  lse               drivers/fc4/fc.c
 
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GDTIOCTL_MAGIC        0x06030f07  gdth_iowr_str     drivers/scsi/gdth_ioctl.h
 
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RIEBL_MAGIC           0x09051990                    drivers/net/atarilance.c
 
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RIO_MAGIC             0x12345678  gs_port           drivers/char/rio/rio_linux.c
 
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SX_MAGIC              0x12345678  gs_port           drivers/char/sx.h
 
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NBD_REQUEST_MAGIC     0x12560953  nbd_request       include/linux/nbd.h
 
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RED_MAGIC2            0x170fc2a5  (any)             mm/slab.c
 
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BAYCOM_MAGIC          0x19730510  baycom_state      drivers/net/baycom_epp.c
 
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ISDN_X25IFACE_MAGIC   0x1e75a2b9  isdn_x25iface_proto_data
 
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                                                    drivers/isdn/isdn_x25iface.h
 
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ECP_MAGIC             0x21504345  cdkecpsig         include/linux/cdk.h
 
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LSOMAGIC              0x27091997  lso               drivers/fc4/fc.c
 
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LSMAGIC               0x2a3b4d2a  ls                drivers/fc4/fc.c
 
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WANPIPE_MAGIC         0x414C4453  sdla_{dump,exec}  include/linux/wanpipe.h
 
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CS_CARD_MAGIC         0x43525553  cs_card           sound/oss/cs46xx.c
 
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LABELCL_MAGIC         0x4857434c  labelcl_info_s    include/asm/ia64/sn/labelcl.h
 
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ISDN_ASYNC_MAGIC      0x49344C01  modem_info        include/linux/isdn.h
 
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CTC_ASYNC_MAGIC       0x49344C01  ctc_tty_info      drivers/s390/net/ctctty.c
 
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ISDN_NET_MAGIC        0x49344C02  isdn_net_local_s  drivers/isdn/i4l/isdn_net_lib.h
 
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SAVEKMSG_MAGIC2       0x4B4D5347  savekmsg          arch/*/amiga/config.c
 
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STLI_BOARDMAGIC       0x4bc6c825  stlibrd           include/linux/istallion.h
 
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CS_STATE_MAGIC        0x4c4f4749  cs_state          sound/oss/cs46xx.c
 
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SLAB_C_MAGIC          0x4f17a36d  kmem_cache        mm/slab.c
 
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COW_MAGIC             0x4f4f4f4d  cow_header_v1     arch/um/drivers/ubd_user.c
 
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I810_CARD_MAGIC       0x5072696E  i810_card         sound/oss/i810_audio.c
 
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TRIDENT_CARD_MAGIC    0x5072696E  trident_card      sound/oss/trident.c
 
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ROUTER_MAGIC          0x524d4157  wan_device        include/linux/wanrouter.h
 
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SCC_MAGIC             0x52696368  gs_port           drivers/char/scc.h
 
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SAVEKMSG_MAGIC1       0x53415645  savekmsg          arch/*/amiga/config.c
 
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GDA_MAGIC             0x58464552  gda               arch/mips/include/asm/sn/gda.h
 
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RED_MAGIC1            0x5a2cf071  (any)             mm/slab.c
 
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STL_PORTMAGIC         0x5a7182c9  stlport           include/linux/stallion.h
 
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EEPROM_MAGIC_VALUE    0x5ab478d2  lanai_dev         drivers/atm/lanai.c
 
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HDLCDRV_MAGIC         0x5ac6e778  hdlcdrv_state     include/linux/hdlcdrv.h
 
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EPCA_MAGIC            0x5c6df104  channel           include/linux/epca.h
 
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PCXX_MAGIC            0x5c6df104  channel           drivers/char/pcxx.h
 
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KV_MAGIC              0x5f4b565f  kernel_vars_s     arch/mips/include/asm/sn/klkernvars.h
 
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I810_STATE_MAGIC      0x63657373  i810_state        sound/oss/i810_audio.c
 
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TRIDENT_STATE_MAGIC   0x63657373  trient_state      sound/oss/trident.c
 
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M3_CARD_MAGIC         0x646e6f50  m3_card           sound/oss/maestro3.c
 
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FW_HEADER_MAGIC       0x65726F66  fw_header         drivers/atm/fore200e.h
 
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SLOT_MAGIC            0x67267321  slot              drivers/hotplug/cpqphp.h
 
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SLOT_MAGIC            0x67267322  slot              drivers/hotplug/acpiphp.h
 
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LO_MAGIC              0x68797548  nbd_device        include/linux/nbd.h
 
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OPROFILE_MAGIC        0x6f70726f  super_block       drivers/oprofile/oprofilefs.h
 
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M3_STATE_MAGIC        0x734d724d  m3_state          sound/oss/maestro3.c
 
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STL_PANELMAGIC        0x7ef621a1  stlpanel          include/linux/stallion.h
 
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VMALLOC_MAGIC         0x87654320  snd_alloc_track   sound/core/memory.c
 
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KMALLOC_MAGIC         0x87654321  snd_alloc_track   sound/core/memory.c
 
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PWC_MAGIC             0x89DC10AB  pwc_device        drivers/usb/media/pwc.h
 
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NBD_REPLY_MAGIC       0x96744668  nbd_reply         include/linux/nbd.h
 
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STL_BOARDMAGIC        0xa2267f52  stlbrd            include/linux/stallion.h
 
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ENI155_MAGIC          0xa54b872d  midway_eprom      drivers/atm/eni.h
 
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SCI_MAGIC             0xbabeface  gs_port           drivers/char/sh-sci.h
 
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CODA_MAGIC            0xC0DAC0DA  coda_file_info    fs/coda/coda_fs_i.h
 
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DPMEM_MAGIC           0xc0ffee11  gdt_pci_sram      drivers/scsi/gdth.h
 
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STLI_PORTMAGIC        0xe671c7a1  stliport          include/linux/istallion.h
 
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YAM_MAGIC             0xF10A7654  yam_port          drivers/net/hamradio/yam.c
 
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CCB_MAGIC             0xf2691ad2  ccb               drivers/scsi/ncr53c8xx.c
 
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QUEUE_MAGIC_FREE      0xf7e1c9a3  queue_entry       drivers/scsi/arm/queue.c
 
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QUEUE_MAGIC_USED      0xf7e1cc33  queue_entry       drivers/scsi/arm/queue.c
 
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HTB_CMAGIC            0xFEFAFEF1  htb_class         net/sched/sch_htb.c
 
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NMI_MAGIC             0x48414d4d455201 nmi_s        arch/mips/include/asm/sn/nmi.h
 
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Note that there are also defined special per-driver magic numbers in sound
 
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memory management. See include/sound/sndmagic.h for complete list of them. Many
 
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OSS sound drivers have their magic numbers constructed from the soundcard PCI
 
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ID - these are not listed here as well.
 
167
 
 
168
IrDA subsystem also uses large number of own magic numbers, see
 
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include/net/irda/irda.h for a complete list of them.
 
170
 
 
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HFS is another larger user of magic numbers - you can find them in
 
172
fs/hfs/hfs.h.