ide: /proc/ide/hd*/settings rework

* Add struct ide_devset, S_* flags, *DEVSET() & ide*_devset_*() macros.

* Add 'const struct ide_devset **settings' to ide_driver_t.

* Use 'const struct ide_devset **settings' in ide_drive_t instead of
  'struct ide_settings_s *settings'.  Then convert core code and device
  drivers to use struct ide_devset and co.:

  - device settings are no longer allocated dynamically for each device
    but instead there is an unique struct ide_devset instance per setting

  - device driver keeps the pointer to the table of pointers to its
    settings in ide_driver_t.settings

  - generic settings are kept in ide_generic_setting[]

  - ide_proc_[un]register_driver(), ide_find_setting_by_name(),
    ide_{read,write}_setting() and proc_ide_{read,write}_settings()
    are updated accordingly

  - ide*_add_settings() are removed

* Remove no longer used __ide_add_setting(), ide_add_setting(),
  __ide_remove_setting() and auto_remove_settings().

* Remove no longer used TYPE_*, SETTING_*, ide_procset_t
  and ide_settings_t.

* ->keep_settings, ->using_dma, ->unmask, ->noflush, ->dsc_overlap,
  ->nice1, ->addressing, ->wcache and ->nowerr ide_drive_t fields
  can now be bitfield flags.

While at it:

* Rename ide_find_setting_by_name() to ide_find_setting().

* Rename write_wcache() to set_wcache().

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide.c

@@ -287,6 +287,8 @@ int ide_spin_wait_hwgroup (ide_drive_t *drive)
 
 EXPORT_SYMBOL(ide_spin_wait_hwgroup);
 
+ide_devset_get(io_32bit, io_32bit);
+
 int set_io_32bit(ide_drive_t *drive, int arg)
 {
 	if (drive->no_io_32bit)
@@ -305,6 +307,8 @@ int set_io_32bit(ide_drive_t *drive, int arg)
 	return 0;
 }
 
+ide_devset_get(ksettings, keep_settings);
+
 int set_ksettings(ide_drive_t *drive, int arg)
 {
 	if (arg < 0 || arg > 1)
@@ -318,6 +322,8 @@ int set_ksettings(ide_drive_t *drive, int arg)
 	return 0;
 }
 
+ide_devset_get(using_dma, using_dma);
+
 int set_using_dma(ide_drive_t *drive, int arg)
 {
 #ifdef CONFIG_BLK_DEV_IDEDMA
@@ -394,6 +400,8 @@ int set_pio_mode(ide_drive_t *drive, int arg)
 	return 0;
 }
 
+ide_devset_get(unmaskirq, unmask);
+
 int set_unmaskirq(ide_drive_t *drive, int arg)
 {
 	if (drive->no_unmask)
@@ -555,14 +563,13 @@ int generic_ide_ioctl(ide_drive_t *drive, struct file *file, struct block_device
 {
 	unsigned long flags;
 	ide_driver_t *drv;
-	int err = 0, (*setfunc)(ide_drive_t *, int);
-	u8 *val;
+	int err = 0, (*getfunc)(ide_drive_t *), (*setfunc)(ide_drive_t *, int);
 
 	switch (cmd) {
-	case HDIO_GET_32BIT:	    val = &drive->io_32bit;	 goto read_val;
-	case HDIO_GET_KEEPSETTINGS: val = &drive->keep_settings; goto read_val;
-	case HDIO_GET_UNMASKINTR:   val = &drive->unmask;	 goto read_val;
-	case HDIO_GET_DMA:	    val = &drive->using_dma;	 goto read_val;
+	case HDIO_GET_32BIT:	    getfunc = get_io_32bit;	 goto read_val;
+	case HDIO_GET_KEEPSETTINGS: getfunc = get_ksettings;	 goto read_val;
+	case HDIO_GET_UNMASKINTR:   getfunc = get_unmaskirq;	 goto read_val;
+	case HDIO_GET_DMA:	    getfunc = get_using_dma;	 goto read_val;
 	case HDIO_SET_32BIT:	    setfunc = set_io_32bit;	 goto set_val;
 	case HDIO_SET_KEEPSETTINGS: setfunc = set_ksettings;	 goto set_val;
 	case HDIO_SET_PIO_MODE:	    setfunc = set_pio_mode;	 goto set_val;
@@ -638,7 +645,7 @@ int generic_ide_ioctl(ide_drive_t *drive, struct file *file, struct block_device
 read_val:
 	mutex_lock(&ide_setting_mtx);
 	spin_lock_irqsave(&ide_lock, flags);
-	err = *val;
+	err = getfunc(drive);
 	spin_unlock_irqrestore(&ide_lock, flags);
 	mutex_unlock(&ide_setting_mtx);
 	return err >= 0 ? put_user(err, (long __user *)arg) : err;