[PATCH] ide.c: use less stack in ide_unregister()

From: Chris Wedgwood <cw@f00f.org>

Seperate function, cruft removed and old_hwif
renamed to something less confusing.

drivers/ide/ide.c

@@ -585,6 +585,102 @@ void ide_hwif_release_regions(ide_hwif_t *hwif)
 
 EXPORT_SYMBOL(ide_hwif_release_regions);
 
+/* restore hwif to a sane state */
+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->atapi_dma			= tmp_hwif->atapi_dma;
+	hwif->ultra_mask		= tmp_hwif->ultra_mask;
+	hwif->mwdma_mask		= tmp_hwif->mwdma_mask;
+	hwif->swdma_mask		= tmp_hwif->swdma_mask;
+
+	hwif->chipset			= tmp_hwif->chipset;
+	hwif->hold			= tmp_hwif->hold;
+
+#ifdef CONFIG_BLK_DEV_IDEPCI
+	hwif->pci_dev			= tmp_hwif->pci_dev;
+	hwif->cds			= tmp_hwif->cds;
+#endif
+
+	hwif->identify			= tmp_hwif->identify;
+	hwif->tuneproc			= tmp_hwif->tuneproc;
+	hwif->speedproc			= tmp_hwif->speedproc;
+	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->intrproc			= tmp_hwif->intrproc;
+	hwif->maskproc			= tmp_hwif->maskproc;
+	hwif->quirkproc			= tmp_hwif->quirkproc;
+	hwif->busproc			= tmp_hwif->busproc;
+
+	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->ide_dma_read		= tmp_hwif->ide_dma_read;
+	hwif->ide_dma_write		= tmp_hwif->ide_dma_write;
+	hwif->ide_dma_begin		= tmp_hwif->ide_dma_begin;
+	hwif->ide_dma_end		= tmp_hwif->ide_dma_end;
+	hwif->ide_dma_check		= tmp_hwif->ide_dma_check;
+	hwif->ide_dma_on		= tmp_hwif->ide_dma_on;
+	hwif->ide_dma_off_quietly	= tmp_hwif->ide_dma_off_quietly;
+	hwif->ide_dma_test_irq		= tmp_hwif->ide_dma_test_irq;
+	hwif->ide_dma_host_on		= tmp_hwif->ide_dma_host_on;
+	hwif->ide_dma_host_off		= tmp_hwif->ide_dma_host_off;
+	hwif->ide_dma_verbose		= tmp_hwif->ide_dma_verbose;
+	hwif->ide_dma_lostirq		= tmp_hwif->ide_dma_lostirq;
+	hwif->ide_dma_timeout		= tmp_hwif->ide_dma_timeout;
+
+	hwif->OUTB			= tmp_hwif->OUTB;
+	hwif->OUTBSYNC			= tmp_hwif->OUTBSYNC;
+	hwif->OUTW			= tmp_hwif->OUTW;
+	hwif->OUTL			= tmp_hwif->OUTL;
+	hwif->OUTSW			= tmp_hwif->OUTSW;
+	hwif->OUTSL			= tmp_hwif->OUTSL;
+
+	hwif->INB			= tmp_hwif->INB;
+	hwif->INW			= tmp_hwif->INW;
+	hwif->INL			= tmp_hwif->INL;
+	hwif->INSW			= tmp_hwif->INSW;
+	hwif->INSL			= tmp_hwif->INSL;
+
+	hwif->mmio			= tmp_hwif->mmio;
+	hwif->rqsize			= tmp_hwif->rqsize;
+	hwif->no_lba48			= tmp_hwif->no_lba48;
+
+#ifndef CONFIG_BLK_DEV_IDECS
+	hwif->irq			= tmp_hwif->irq;
+#endif
+
+	hwif->dma_base			= tmp_hwif->dma_base;
+	hwif->dma_master		= tmp_hwif->dma_master;
+	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->dma_extra			= tmp_hwif->dma_extra;
+	hwif->config_data		= tmp_hwif->config_data;
+	hwif->select_data		= tmp_hwif->select_data;
+	hwif->autodma			= tmp_hwif->autodma;
+	hwif->udma_four			= tmp_hwif->udma_four;
+	hwif->no_dsc			= tmp_hwif->no_dsc;
+
+	hwif->hwif_data			= tmp_hwif->hwif_data;
+}
+
 /**
  *	ide_unregister		-	free an ide interface
  *	@index: index of interface (will change soon to a pointer)
@@ -606,18 +702,22 @@ EXPORT_SYMBOL(ide_hwif_release_regions);
  *	Unregister restores the hwif structures to the default state.
  *	This is raving bonkers.
  */
- 
-void ide_unregister (unsigned int index)
+
+void ide_unregister(unsigned int index)
 {
 	ide_drive_t *drive;
-	ide_hwif_t *hwif, *g;
+	ide_hwif_t *hwif, *g, *tmp_hwif;
 	ide_hwgroup_t *hwgroup;
 	int irq_count = 0, unit, i;
-	ide_hwif_t old_hwif;
 
-	if (index >= MAX_HWIFS)
-		BUG();
-		
+	BUG_ON(index >= MAX_HWIFS);
+
+	tmp_hwif = kmalloc(sizeof(*tmp_hwif), GFP_KERNEL|__GFP_NOFAIL);
+	if (!tmp_hwif) {
+		printk(KERN_ERR "%s: unable to allocate memory\n", __FUNCTION__);
+		return;
+	}
+
 	BUG_ON(in_interrupt());
 	BUG_ON(irqs_disabled());
 	down(&ide_cfg_sem);
@@ -634,7 +734,7 @@ void ide_unregister (unsigned int index)
 		drive->dead = 1;
 	}
 	hwif->present = 0;
-	
+
 	spin_unlock_irq(&ide_lock);
 
 	for (unit = 0; unit < MAX_DRIVES; ++unit) {
@@ -643,7 +743,7 @@ void ide_unregister (unsigned int index)
 			continue;
 		DRIVER(drive)->cleanup(drive);
 	}
-	
+
 #ifdef CONFIG_PROC_FS
 	destroy_proc_ide_drives(hwif);
 #endif
@@ -763,122 +863,20 @@ void ide_unregister (unsigned int index)
 		hwif->dma_prdtable = 0;
 	}
 
-	old_hwif			= *hwif;
+	/* copy original settings */
+	*tmp_hwif = *hwif;
 
-	init_hwif_data(hwif, index);	/* restore hwif data to pristine status */
+	/* restore hwif data to pristine status */
+	init_hwif_data(hwif, index);
 	init_hwif_default(hwif, index);
 
-	hwif->hwgroup			= old_hwif.hwgroup;
-
-	hwif->gendev.parent		= old_hwif.gendev.parent;
-
-	hwif->proc			= old_hwif.proc;
-
-	hwif->major			= old_hwif.major;
-//	hwif->index			= old_hwif.index;
-//	hwif->channel			= old_hwif.channel;
-	hwif->straight8			= old_hwif.straight8;
-	hwif->bus_state			= old_hwif.bus_state;
-
-	hwif->atapi_dma			= old_hwif.atapi_dma;
-	hwif->ultra_mask		= old_hwif.ultra_mask;
-	hwif->mwdma_mask		= old_hwif.mwdma_mask;
-	hwif->swdma_mask		= old_hwif.swdma_mask;
-
-	hwif->chipset			= old_hwif.chipset;
-	hwif->hold			= old_hwif.hold;
-
-#ifdef CONFIG_BLK_DEV_IDEPCI
-	hwif->pci_dev			= old_hwif.pci_dev;
-	hwif->cds			= old_hwif.cds;
-#endif /* CONFIG_BLK_DEV_IDEPCI */
-
-#if 0
-	hwif->hwifops			= old_hwif.hwifops;
-#else
-	hwif->identify			= old_hwif.identify;
-	hwif->tuneproc			= old_hwif.tuneproc;
-	hwif->speedproc			= old_hwif.speedproc;
-	hwif->selectproc		= old_hwif.selectproc;
-	hwif->reset_poll		= old_hwif.reset_poll;
-	hwif->pre_reset			= old_hwif.pre_reset;
-	hwif->resetproc			= old_hwif.resetproc;
-	hwif->intrproc			= old_hwif.intrproc;
-	hwif->maskproc			= old_hwif.maskproc;
-	hwif->quirkproc			= old_hwif.quirkproc;
-	hwif->busproc			= old_hwif.busproc;
-#endif
-
-#if 0
-	hwif->pioops			= old_hwif.pioops;
-#else
-	hwif->ata_input_data		= old_hwif.ata_input_data;
-	hwif->ata_output_data		= old_hwif.ata_output_data;
-	hwif->atapi_input_bytes		= old_hwif.atapi_input_bytes;
-	hwif->atapi_output_bytes	= old_hwif.atapi_output_bytes;
-#endif
+	ide_hwif_restore(hwif, tmp_hwif);
 
-#if 0
-	hwif->dmaops			= old_hwif.dmaops;
-#else
-	hwif->ide_dma_read		= old_hwif.ide_dma_read;
-	hwif->ide_dma_write		= old_hwif.ide_dma_write;
-	hwif->ide_dma_begin		= old_hwif.ide_dma_begin;
-	hwif->ide_dma_end		= old_hwif.ide_dma_end;
-	hwif->ide_dma_check		= old_hwif.ide_dma_check;
-	hwif->ide_dma_on		= old_hwif.ide_dma_on;
-	hwif->ide_dma_off_quietly	= old_hwif.ide_dma_off_quietly;
-	hwif->ide_dma_test_irq		= old_hwif.ide_dma_test_irq;
-	hwif->ide_dma_host_on		= old_hwif.ide_dma_host_on;
-	hwif->ide_dma_host_off		= old_hwif.ide_dma_host_off;
-	hwif->ide_dma_verbose		= old_hwif.ide_dma_verbose;
-	hwif->ide_dma_lostirq		= old_hwif.ide_dma_lostirq;
-	hwif->ide_dma_timeout		= old_hwif.ide_dma_timeout;
-#endif
-
-#if 0
-	hwif->iops			= old_hwif.iops;
-#else
-	hwif->OUTB		= old_hwif.OUTB;
-	hwif->OUTBSYNC		= old_hwif.OUTBSYNC;
-	hwif->OUTW		= old_hwif.OUTW;
-	hwif->OUTL		= old_hwif.OUTL;
-	hwif->OUTSW		= old_hwif.OUTSW;
-	hwif->OUTSL		= old_hwif.OUTSL;
-
-	hwif->INB		= old_hwif.INB;
-	hwif->INW		= old_hwif.INW;
-	hwif->INL		= old_hwif.INL;
-	hwif->INSW		= old_hwif.INSW;
-	hwif->INSL		= old_hwif.INSL;
-#endif
-
-	hwif->mmio			= old_hwif.mmio;
-	hwif->rqsize			= old_hwif.rqsize;
-	hwif->no_lba48			= old_hwif.no_lba48;
-#ifndef CONFIG_BLK_DEV_IDECS
-	hwif->irq			= old_hwif.irq;
-#endif /* CONFIG_BLK_DEV_IDECS */
-
-	hwif->dma_base			= old_hwif.dma_base;
-	hwif->dma_master		= old_hwif.dma_master;
-	hwif->dma_command		= old_hwif.dma_command;
-	hwif->dma_vendor1		= old_hwif.dma_vendor1;
-	hwif->dma_status		= old_hwif.dma_status;
-	hwif->dma_vendor3		= old_hwif.dma_vendor3;
-	hwif->dma_prdtable		= old_hwif.dma_prdtable;
-
-	hwif->dma_extra			= old_hwif.dma_extra;
-	hwif->config_data		= old_hwif.config_data;
-	hwif->select_data		= old_hwif.select_data;
-	hwif->autodma			= old_hwif.autodma;
-	hwif->udma_four			= old_hwif.udma_four;
-	hwif->no_dsc			= old_hwif.no_dsc;
-
-	hwif->hwif_data			= old_hwif.hwif_data;
 abort:
 	spin_unlock_irq(&ide_lock);
 	up(&ide_cfg_sem);
+
+	kfree(tmp_hwif);
 }
 
 EXPORT_SYMBOL(ide_unregister);