[PATCH] 2.5.10 IDE 44

Reduce the "rain forest" of pointers a bit.

- Use the channel info from the drive instead of from hwgroup where possible.
   Since we have now a direct association between a channel and irq, we can fix
   the handler for unexpected interrupts to don't have to iterate over multiple
   possibilities.

- Finally it was just possible to remove the circular list of channels
   associated with a hwif. The hwif member of struct hwgroup_s as well as
   next member if struct ata_channel are gone.

- Unify ide_build_sglist() and raw_build_sglist() in to one function.  Use the
   queue associated with a request in the case of a CMD request there instead of
   referencing the device minor number. This will be pushed even further later.

arch/m68k/mac/baboon.c

@@ -27,7 +27,9 @@ volatile struct baboon *baboon;
 
 void baboon_irq(int, void *, struct pt_regs *);
 
+#if 0
 extern int macide_ack_intr(struct ata_channel *);
+#endif
 
 /*
  * Baboon initialization.

drivers/ide/ide-dma.c

@@ -5,9 +5,7 @@
  *  May be copied or modified under the terms of the GNU General Public License
  *
  *  Special Thanks to Mark for his Six years of work.
- */
-
-/*
+*
  * This module provides support for the bus-master IDE DMA functions
  * of various PCI chipsets, including the Intel PIIX (i82371FB for
  * the 430 FX chipset), the PIIX3 (i82371SB for the 430 HX/VX and
@@ -215,33 +213,16 @@ ide_startstop_t ide_dma_intr (ide_drive_t *drive)
 	return ide_error(drive, "dma_intr", stat);
 }
 
-static int ide_build_sglist(struct ata_channel *hwif, struct request *rq)
-{
-	request_queue_t *q = &hwif->drives[DEVICE_NR(rq->rq_dev) & 1].queue;
-	struct scatterlist *sg = hwif->sg_table;
-	int nents;
-
-	nents = blk_rq_map_sg(q, rq, hwif->sg_table);
-
-	if (rq->q && nents > rq->nr_phys_segments)
-		printk("ide-dma: received %d phys segments, build %d\n", rq->nr_phys_segments, nents);
-
-	if (rq_data_dir(rq) == READ)
-		hwif->sg_dma_direction = PCI_DMA_FROMDEVICE;
-	else
-		hwif->sg_dma_direction = PCI_DMA_TODEVICE;
-
-	return pci_map_sg(hwif->pci_dev, sg, nents, hwif->sg_dma_direction);
-}
-
 /*
  * FIXME: taskfiles should be a map of pages, not a long virt address... /jens
  * FIXME: I agree with Jens --mdcki!
  */
-static int raw_build_sglist(struct ata_channel *ch, struct request *rq)
+static int build_sglist(struct ata_channel *ch, struct request *rq)
 {
 	struct scatterlist *sg = ch->sg_table;
 	int nents = 0;
+
+	if (rq->flags & REQ_DRIVE_ACB) {
 		struct ata_taskfile *args = rq->special;
 #if 1
 		unsigned char *virt_addr = rq->buffer;
@@ -258,13 +239,16 @@ static int raw_build_sglist(struct ata_channel *ch, struct request *rq)
 		else
 			ch->sg_dma_direction = PCI_DMA_FROMDEVICE;
 
+		/*
+		 * FIXME: This depends upon a hard coded page size!
+		 */
 		if (sector_count > 128) {
 			memset(&sg[nents], 0, sizeof(*sg));
 
 			sg[nents].page = virt_to_page(virt_addr);
 			sg[nents].offset = (unsigned long) virt_addr & ~PAGE_MASK;
 			sg[nents].length = 128  * SECTOR_SIZE;
-		nents++;
+			++nents;
 			virt_addr = virt_addr + (128 * SECTOR_SIZE);
 			sector_count -= 128;
 		}
@@ -272,8 +256,19 @@ static int raw_build_sglist(struct ata_channel *ch, struct request *rq)
 		sg[nents].page = virt_to_page(virt_addr);
 		sg[nents].offset = (unsigned long) virt_addr & ~PAGE_MASK;
 		sg[nents].length =  sector_count  * SECTOR_SIZE;
-	nents++;
+		++nents;
+	} else {
+		nents = blk_rq_map_sg(rq->q, rq, ch->sg_table);
 
+		if (rq->q && nents > rq->nr_phys_segments)
+			printk("ide-dma: received %d phys segments, build %d\n", rq->nr_phys_segments, nents);
+
+		if (rq_data_dir(rq) == READ)
+			ch->sg_dma_direction = PCI_DMA_FROMDEVICE;
+		else
+			ch->sg_dma_direction = PCI_DMA_TODEVICE;
+
+	}
 	return pci_map_sg(ch->pci_dev, sg, nents, ch->sg_dma_direction);
 }
 
@@ -295,11 +290,7 @@ int ide_build_dmatable (ide_drive_t *drive, ide_dma_action_t func)
 	int i;
 	struct scatterlist *sg;
 
-	if (HWGROUP(drive)->rq->flags & REQ_DRIVE_ACB) {
-		hwif->sg_nents = i = raw_build_sglist(hwif, HWGROUP(drive)->rq);
-	} else {
-		hwif->sg_nents = i = ide_build_sglist(hwif, HWGROUP(drive)->rq);
-	}
+	hwif->sg_nents = i = build_sglist(hwif, HWGROUP(drive)->rq);
 	if (!i)
 		return 0;
 

drivers/ide/ide-probe.c

@@ -633,7 +633,7 @@ static void save_match(struct ata_channel *hwif, struct ata_channel *new,
 static int init_irq(struct ata_channel *ch)
 {
 	unsigned long flags;
-	unsigned int index;
+	int i;
 	ide_hwgroup_t *hwgroup;
 	ide_hwgroup_t *new_hwgroup;
 	struct ata_channel *match = NULL;
@@ -650,8 +650,9 @@ static int init_irq(struct ata_channel *ch)
 	/*
 	 * Group up with any other channels that share our irq(s).
 	 */
-	for (index = 0; index < MAX_HWIFS; index++) {
-		struct ata_channel *h = &ide_hwifs[index];
+	for (i = 0; i < MAX_HWIFS; ++i) {
+		struct ata_channel *h = &ide_hwifs[i];
+
 		if (h->hwgroup) {  /* scan only initialized channels */
 			if (ch->irq == h->irq) {
 				ch->sharing_irq = h->sharing_irq = 1;
@@ -682,7 +683,6 @@ static int init_irq(struct ata_channel *ch)
 			return 1;
 		}
 		memset(hwgroup, 0, sizeof(ide_hwgroup_t));
-		hwgroup->hwif     = ch->next = ch;
 		hwgroup->rq       = NULL;
 		hwgroup->handler  = NULL;
 		hwgroup->drive    = NULL;
@@ -716,14 +716,12 @@ static int init_irq(struct ata_channel *ch)
 	}
 
 	/*
-	 * Everything is okay, so link us into the hwgroup.
+	 * Everything is okay.
 	 */
 	ch->hwgroup = hwgroup;
-	ch->next = hwgroup->hwif->next;
-	hwgroup->hwif->next = ch;
 
-	for (index = 0; index < MAX_DRIVES; ++index) {
-		struct ata_device *drive = &ch->drives[index];
+	for (i = 0; i < MAX_DRIVES; ++i) {
+		struct ata_device *drive = &ch->drives[i];
 
 		if (!drive->present)
 			continue;
@@ -736,12 +734,6 @@ static int init_irq(struct ata_channel *ch)
 
 		init_device_queue(drive);
 	}
-	if (!hwgroup->hwif) {
-		hwgroup->hwif = hwgroup->drive->channel;
-#ifdef DEBUG
-		printk("%s : Adding missed channel to hwgroup!!\n", ch->name);
-#endif
-	}
 	spin_unlock_irqrestore(&ide_lock, flags);
 
 #if !defined(__mc68000__) && !defined(CONFIG_APUS) && !defined(__sparc__)
@@ -762,6 +754,7 @@ static int init_irq(struct ata_channel *ch)
 		printk(" (%sed with %s)",
 			ch->sharing_irq ? "shar" : "serializ", match->name);
 	printk("\n");
+
 	return 0;
 }
 

include/linux/ide.h

@@ -73,7 +73,6 @@ typedef unsigned char	byte;	/* used everywhere */
  */
 #define DMA_PIO_RETRY	1	/* retrying in PIO */
 
-#define HWIF(drive)		((drive)->channel)
 #define HWGROUP(drive)		(drive->channel->hwgroup)
 
 /*
@@ -254,7 +253,7 @@ void ide_setup_ports(hw_regs_t *hw,
 #endif
 
 /*
- * Now for the data we need to maintain per-drive:  ide_drive_t
+ * Device types - the nomenclature is analogous to SCSI code.
  */
 
 #define ATA_DISK        0x20
@@ -266,7 +265,10 @@ void ide_setup_ports(hw_regs_t *hw,
 #define ATA_NO_LUN      0x7f
 
 struct ide_settings_s;
-/* structure describing an ATA/ATAPI device */
+
+/*
+ * ATA/ATAPI device structure :
+ */
 typedef
 struct ata_device {
 	struct ata_channel *	channel;
@@ -401,7 +403,6 @@ struct ata_channel {
 	struct device	dev;		/* device handle */
 	int		unit;		/* channel number */
 
-	struct ata_channel *next;	/* for linked-list in ide_hwgroup_t */
 	struct hwgroup_s *hwgroup;	/* actually (ide_hwgroup_t *) */
 
 	ide_ioreg_t	io_ports[IDE_NR_PORTS];	/* task file registers */
@@ -516,13 +517,10 @@ typedef int (ide_expiry_t)(ide_drive_t *);
 #define IDE_DMA		2	/* DMA in progress */
 
 typedef struct hwgroup_s {
-	ide_handler_t		*handler;/* irq handler, if active */
+	ide_handler_t *handler;		/* irq handler, if active */
 	unsigned long flags;		/* BUSY, SLEEPING */
-	ide_drive_t		*drive;	/* current drive */
-	struct ata_channel	*hwif;	/* ptr to current hwif in linked-list */
-
+	struct ata_device *drive;	/* current drive */
 	struct request *rq;		/* current request */
-
 	struct timer_list timer;	/* failsafe timer */
 	struct request wrq;		/* local copy of current write rq */
 	unsigned long poll_timeout;	/* timeout value during long polls */