ide: remove broken/dangerous HDIO_[UNREGISTER,SCAN]_HWIF ioctls (take 3)

hdparm explicitely marks HDIO_[UNREGISTER,SCAN]_HWIF ioctls as DANGEROUS
and given the number of bugs we can assume that there are no real users:

* DMA has no chance of working because DMA resources are released by
  ide_unregister() and they are never allocated again.

* Since ide_init_hwif_ports() is used for ->io_ports[] setup the ioctls
  don't work for almost all hosts with "non-standard" (== non ISA-like)
  layout of IDE taskfile registers (there is a lot of such host drivers).

* ide_port_init_devices() is not called when probing IDE devices so:
  - drive->autotune is never set and IDE host/devices are not programmed
    for the correct PIO/DMA transfer modes (=> possible data corruption)
  - host specific I/O 32-bit and IRQ unmasking settings are not applied
    (=> possible data corruption)
  - host specific ->port_init_devs method is not called (=> no luck with
    ht6560b, qd65xx and opti621 host drivers)

* ->rw_disk method is not preserved (=> no HPT3xxN chipsets support).

* ->serialized flag is not preserved (=> possible data corruption when
   using icside, aec62xx (ATP850UF chipset), cmd640, cs5530, hpt366
   (HPT3xxN chipsets), rz1000, sc1200, dtc2278 and ht6560b host drivers).

* ->ack_intr method is not preserved (=> needed by ide-cris, buddha,
  gayle and macide host drivers).

* ->sata_scr[] and sata_misc[] is cleared by ide_unregister() and it
  isn't initialized again (SiI3112 support needs them).

* To issue an ioctl() there need to be at least one IDE device present
  in the system.

* ->cable_detect method is not preserved + it is not called when probing
  IDE devices so cable detection is broken (however since DMA support is
  also broken it doesn't really matter ;-).

* Some objects which may have already been freed in ide_unregister()
  are restored by ide_hwif_restore() (i.e. ->hwgroup).

* ide_register_hw() may unregister unrelated IDE ports if free ide_hwifs[]
  slot cannot be found.

* When IDE host drivers are modular unregistered port may be re-used by
  different host driver that owned it first causing subtle bugs.

Since we now have a proper warm-plug support remove these ioctls,
then remove no longer needed:
- ide_register_hw() and ide_hwif_restore() functions
- 'init_default' and 'restore' arguments of ide_unregister()
- zeroeing of hwif->{dma,extra}_* fields in ide_unregister()

As an added bonus IDE core code size shrinks by ~3kB (x86-32).

v2:
* fix ide_unregister() arguments in cleanup_module() (Andrew Morton).

v3:
* fix ide_unregister() arguments in palm_bk3710.c.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 4 insertions, 195 deletions

diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index 7e789c97a8b8..1121d9cb2a9b 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -362,107 +362,6 @@ void ide_hwif_release_regions(ide_hwif_t *hwif)
                         release_region(hwif->io_ports[i], 1);
 }
 
-/**
- *      ide_hwif_restore        -       restore hwif to template
- *      @hwif: hwif to update
- *      @tmp_hwif: template
- *
- *      Restore hwif to a previous state by copying most settings
- *      from the template.
- */
-
-static void ide_hwif_restore(ide_hwif_t *hwif, ide_hwif_t *tmp_hwif)
-{
-        hwif->hwgroup                   = tmp_hwif->hwgroup;
-
-        hwif->gendev.parent             = tmp_hwif->gendev.parent;
-
-        hwif->proc                      = tmp_hwif->proc;
-
-        hwif->major                     = tmp_hwif->major;
-        hwif->straight8                 = tmp_hwif->straight8;
-        hwif->bus_state                 = tmp_hwif->bus_state;
-
-        hwif->host_flags                = tmp_hwif->host_flags;
-
-        hwif->pio_mask                  = tmp_hwif->pio_mask;
-
-        hwif->ultra_mask                = tmp_hwif->ultra_mask;
-        hwif->mwdma_mask                = tmp_hwif->mwdma_mask;
-        hwif->swdma_mask                = tmp_hwif->swdma_mask;
-
-        hwif->cbl                       = tmp_hwif->cbl;
-
-        hwif->chipset                   = tmp_hwif->chipset;
-        hwif->hold                      = tmp_hwif->hold;
-
-        hwif->dev                       = tmp_hwif->dev;
-
-#ifdef CONFIG_BLK_DEV_IDEPCI
-        hwif->cds                       = tmp_hwif->cds;
-#endif
-
-        hwif->set_pio_mode              = tmp_hwif->set_pio_mode;
-        hwif->set_dma_mode              = tmp_hwif->set_dma_mode;
-        hwif->mdma_filter               = tmp_hwif->mdma_filter;
-        hwif->udma_filter               = tmp_hwif->udma_filter;
-        hwif->selectproc                = tmp_hwif->selectproc;
-        hwif->reset_poll                = tmp_hwif->reset_poll;
-        hwif->pre_reset                 = tmp_hwif->pre_reset;
-        hwif->resetproc                 = tmp_hwif->resetproc;
-        hwif->maskproc                  = tmp_hwif->maskproc;
-        hwif->quirkproc                 = tmp_hwif->quirkproc;
-
-        hwif->ata_input_data            = tmp_hwif->ata_input_data;
-        hwif->ata_output_data           = tmp_hwif->ata_output_data;
-        hwif->atapi_input_bytes         = tmp_hwif->atapi_input_bytes;
-        hwif->atapi_output_bytes        = tmp_hwif->atapi_output_bytes;
-
-        hwif->dma_host_set              = tmp_hwif->dma_host_set;
-        hwif->dma_setup                 = tmp_hwif->dma_setup;
-        hwif->dma_exec_cmd              = tmp_hwif->dma_exec_cmd;
-        hwif->dma_start                 = tmp_hwif->dma_start;
-        hwif->ide_dma_end               = tmp_hwif->ide_dma_end;
-        hwif->ide_dma_test_irq          = tmp_hwif->ide_dma_test_irq;
-        hwif->ide_dma_clear_irq         = tmp_hwif->ide_dma_clear_irq;
-        hwif->dma_lost_irq              = tmp_hwif->dma_lost_irq;
-        hwif->dma_timeout               = tmp_hwif->dma_timeout;
-
-        hwif->OUTB                      = tmp_hwif->OUTB;
-        hwif->OUTBSYNC                  = tmp_hwif->OUTBSYNC;
-        hwif->OUTW                      = tmp_hwif->OUTW;
-        hwif->OUTSW                     = tmp_hwif->OUTSW;
-        hwif->OUTSL                     = tmp_hwif->OUTSL;
-
-        hwif->INB                       = tmp_hwif->INB;
-        hwif->INW                       = tmp_hwif->INW;
-        hwif->INSW                      = tmp_hwif->INSW;
-        hwif->INSL                      = tmp_hwif->INSL;
-
-        hwif->sg_max_nents              = tmp_hwif->sg_max_nents;
-
-        hwif->mmio                      = tmp_hwif->mmio;
-        hwif->rqsize                    = tmp_hwif->rqsize;
-
-#ifndef CONFIG_BLK_DEV_IDECS
-        hwif->irq                       = tmp_hwif->irq;
-#endif
-
-        hwif->dma_base                  = tmp_hwif->dma_base;
-        hwif->dma_command               = tmp_hwif->dma_command;
-        hwif->dma_vendor1               = tmp_hwif->dma_vendor1;
-        hwif->dma_status                = tmp_hwif->dma_status;
-        hwif->dma_vendor3               = tmp_hwif->dma_vendor3;
-        hwif->dma_prdtable              = tmp_hwif->dma_prdtable;
-
-        hwif->config_data               = tmp_hwif->config_data;
-        hwif->select_data               = tmp_hwif->select_data;
-        hwif->extra_base                = tmp_hwif->extra_base;
-        hwif->extra_ports               = tmp_hwif->extra_ports;
-
-        hwif->hwif_data                 = tmp_hwif->hwif_data;
-}
-
 void ide_remove_port_from_hwgroup(ide_hwif_t *hwif)
 {
         ide_hwgroup_t *hwgroup = hwif->hwgroup;
@@ -530,8 +429,6 @@ EXPORT_SYMBOL_GPL(ide_port_unregister_devices);
 /**
  *      ide_unregister          -       free an IDE interface
  *      @index: index of interface (will change soon to a pointer)
- *      @init_default: init default hwif flag
- *      @restore: restore hwif flag
  *
  *      Perform the final unregister of an IDE interface. At the moment
  *      we don't refcount interfaces so this will also get split up.
@@ -551,10 +448,9 @@ EXPORT_SYMBOL_GPL(ide_port_unregister_devices);
  *      This is raving bonkers.
  */
 
-void ide_unregister(unsigned int index, int init_default, int restore)
+void ide_unregister(unsigned int index)
 {
         ide_hwif_t *hwif, *g;
-        static ide_hwif_t tmp_hwif; /* protected by ide_cfg_mtx */
         ide_hwgroup_t *hwgroup;
         int irq_count = 0;
 
@@ -601,34 +497,14 @@ void ide_unregister(unsigned int index, int init_default, int restore)
         unregister_blkdev(hwif->major, hwif->name);
         spin_lock_irq(&ide_lock);
 
-        if (hwif->dma_base) {
-                (void) ide_release_dma(hwif);
-
-                hwif->dma_base = 0;
-                hwif->dma_command = 0;
-                hwif->dma_vendor1 = 0;
-                hwif->dma_status = 0;
-                hwif->dma_vendor3 = 0;
-                hwif->dma_prdtable = 0;
-
-                hwif->extra_base  = 0;
-                hwif->extra_ports = 0;
-        }
+        if (hwif->dma_base)
+                (void)ide_release_dma(hwif);
 
         ide_hwif_release_regions(hwif);
 
-        /* copy original settings */
-        tmp_hwif = *hwif;
-
         /* restore hwif data to pristine status */
         ide_init_port_data(hwif, index);
 
-        if (init_default)
-                init_hwif_default(hwif, index);
-
-        if (restore)
-                ide_hwif_restore(hwif, &tmp_hwif);
-
 abort:
         spin_unlock_irq(&ide_lock);
         mutex_unlock(&ide_cfg_mtx);
@@ -647,52 +523,6 @@ void ide_init_port_hw(ide_hwif_t *hwif, hw_regs_t *hw)
 }
 EXPORT_SYMBOL_GPL(ide_init_port_hw);
 
-/**
- *      ide_register_hw         -       register IDE interface
- *      @hw: hardware registers
- *      @quirkproc: quirkproc function
- *      @hwifp: pointer to returned hwif
- *
- *      Register an IDE interface, specifying exactly the registers etc.
- *
- *      Returns -1 on error.
- */
-
-static int ide_register_hw(hw_regs_t *hw, void (*quirkproc)(ide_drive_t *),
-                           ide_hwif_t **hwifp)
-{
-        int index, retry = 1;
-        ide_hwif_t *hwif;
-        u8 idx[4] = { 0xff, 0xff, 0xff, 0xff };
-
-        do {
-                hwif = ide_find_port(hw->io_ports[IDE_DATA_OFFSET]);
-                if (hwif)
-                        goto found;
-                for (index = 0; index < MAX_HWIFS; index++)
-                        ide_unregister(index, 1, 1);
-        } while (retry--);
-        return -1;
-found:
-        index = hwif->index;
-        if (hwif->present)
-                ide_unregister(index, 0, 1);
-        else if (!hwif->hold)
-                ide_init_port_data(hwif, index);
-
-        ide_init_port_hw(hwif, hw);
-        hwif->quirkproc = quirkproc;
-
-        idx[0] = index;
-
-        ide_device_add(idx, NULL);
-
-        if (hwifp)
-                *hwifp = hwif;
-
-        return hwif->present ? index : -1;
-}
-
 /*
  *      Locks for IDE setting functionality
  */
@@ -995,27 +825,6 @@ int generic_ide_ioctl(ide_drive_t *drive, struct file *file, struct block_device
                         if (!capable(CAP_SYS_RAWIO))
                                 return -EACCES;
                         return ide_task_ioctl(drive, cmd, arg);
-
-                case HDIO_SCAN_HWIF:
-                {
-                        hw_regs_t hw;
-                        int args[3];
-                        if (!capable(CAP_SYS_RAWIO)) return -EACCES;
-                        if (copy_from_user(args, p, 3 * sizeof(int)))
-                                return -EFAULT;
-                        memset(&hw, 0, sizeof(hw));
-                        ide_init_hwif_ports(&hw, (unsigned long) args[0],
-                                            (unsigned long) args[1], NULL);
-                        hw.irq = args[2];
-                        if (ide_register_hw(&hw, NULL, NULL) == -1)
-                                return -EIO;
-                        return 0;
-                }
-                case HDIO_UNREGISTER_HWIF:
-                        if (!capable(CAP_SYS_RAWIO)) return -EACCES;
-                        /* (arg > MAX_HWIFS) checked in function */
-                        ide_unregister(arg, 1, 1);
-                        return 0;
                 case HDIO_SET_NICE:
                         if (!capable(CAP_SYS_ADMIN)) return -EACCES;
                         if (arg != (arg & ((1 << IDE_NICE_DSC_OVERLAP) | (1 << IDE_NICE_1))))
@@ -1648,7 +1457,7 @@ void __exit cleanup_module (void)
         int index;
 
         for (index = 0; index < MAX_HWIFS; ++index)
-                ide_unregister(index, 0, 0);
+                ide_unregister(index);
 
         proc_ide_destroy();