[PATCH] capacity related fixes

From Andries.Brouwer@cwi.nl:

- store capacities in sector_t
- add generic sectors_to_MB() helper to ide-disk.c
- fix drive->bios_cyls calculation (limiting it to 65535) for disks

drivers/ide/ide-cd.c

@@ -3228,7 +3228,7 @@ int ide_cdrom_setup (ide_drive_t *drive)
 }
 
 static
-unsigned long ide_cdrom_capacity (ide_drive_t *drive)
+sector_t ide_cdrom_capacity (ide_drive_t *drive)
 {
 	unsigned long capacity;
 

drivers/ide/ide-disk.c

@@ -1066,6 +1066,13 @@ static unsigned long long idedisk_set_max_address_ext(ide_drive_t *drive, unsign
 
 #endif /* CONFIG_IDEDISK_STROKE */
 
+static unsigned long long sectors_to_MB(unsigned long long n)
+{
+	n <<= 9;		/* make it bytes */
+	do_div(n, 1000000);	/* make it MB */
+	return n;
+}
+
 /*
  * Tests if the drive supports Host Protected Area feature.
  * Returns true if supported, false otherwise.
@@ -1166,7 +1173,7 @@ static void init_idedisk_capacity (ide_drive_t  *drive)
 	}
 }
 
-static unsigned long idedisk_capacity (ide_drive_t *drive)
+static sector_t idedisk_capacity (ide_drive_t *drive)
 {
 	if (drive->id->cfs_enable_2 & 0x0400)
 		return (drive->capacity48 - drive->sect0);
@@ -1565,7 +1572,7 @@ static ide_startstop_t idedisk_start_power_step (ide_drive_t *drive, struct requ
 static void idedisk_setup (ide_drive_t *drive)
 {
 	struct hd_driveid *id = drive->id;
-	unsigned long capacity;
+	unsigned long long capacity;
 
 	idedisk_add_settings(drive);
 
@@ -1629,14 +1636,23 @@ static void idedisk_setup (ide_drive_t *drive)
 	 * by correcting bios_cyls:
 	 */
 	capacity = idedisk_capacity (drive);
-	if ((capacity >= (drive->bios_cyl * drive->bios_sect * drive->bios_head)) &&
-	    (!drive->forced_geom) && drive->bios_sect && drive->bios_head)
-		drive->bios_cyl = (capacity / drive->bios_sect) / drive->bios_head;
-	printk (KERN_INFO "%s: %ld sectors", drive->name, capacity);
-
-	/* Give size in megabytes (MB), not mebibytes (MiB). */
-	/* We compute the exact rounded value, avoiding overflow. */
-	printk (" (%ld MB)", (capacity - capacity/625 + 974)/1950);
+	if (!drive->forced_geom && drive->bios_sect && drive->bios_head) {
+		unsigned int cap0 = capacity;	/* truncate to 32 bits */
+		unsigned int cylsz, cyl;
+
+		if (cap0 != capacity)
+			drive->bios_cyl = 65535;
+		else {
+			cylsz = drive->bios_sect * drive->bios_head;
+			cyl = cap0 / cylsz;
+			if (cyl > 65535)
+				cyl = 65535;
+			if (cyl > drive->bios_cyl)
+				drive->bios_cyl = cyl;
+		}
+	}
+	printk(KERN_INFO "%s: %llu sectors (%llu MB)",
+			 drive->name, capacity, sectors_to_MB(capacity));
 
 	/* Only print cache size when it was specified */
 	if (id->buf_size)

drivers/ide/ide-floppy.c

@@ -1626,7 +1626,7 @@ static int idefloppy_get_format_progress(ide_drive_t *drive, int *arg)
 /*
  *	Return the current floppy capacity to ide.c.
  */
-static unsigned long idefloppy_capacity (ide_drive_t *drive)
+static sector_t idefloppy_capacity (ide_drive_t *drive)
 {
 	idefloppy_floppy_t *floppy = drive->driver_data;
 	unsigned long capacity = floppy->blocks * floppy->bs_factor;

drivers/ide/ide.c

@@ -351,7 +351,7 @@ int ide_system_bus_speed (void)
  * current_capacity() returns the capacity (in sectors) of a drive
  * according to its current geometry/LBA settings.
  */
-unsigned long current_capacity (ide_drive_t *drive)
+sector_t current_capacity (ide_drive_t *drive)
 {
 	if (!drive->present)
 		return 0;
@@ -2410,7 +2410,7 @@ static void default_pre_reset (ide_drive_t *drive)
 {
 }
 
-static unsigned long default_capacity (ide_drive_t *drive)
+static sector_t default_capacity (ide_drive_t *drive)
 {
 	return 0x7fffffff;
 }

include/linux/ide.h

@@ -1226,7 +1226,7 @@ typedef struct ide_driver_s {
 	ide_startstop_t	(*abort)(ide_drive_t *, const char *);
 	int		(*ioctl)(ide_drive_t *, struct inode *, struct file *, unsigned int, unsigned long);
 	void		(*pre_reset)(ide_drive_t *);
-	unsigned long	(*capacity)(ide_drive_t *);
+	sector_t	(*capacity)(ide_drive_t *);
 	ide_startstop_t	(*special)(ide_drive_t *);
 	ide_proc_entry_t	*proc;
 	int		(*attach)(ide_drive_t *);
@@ -1359,7 +1359,7 @@ extern int ide_wait_stat(ide_startstop_t *, ide_drive_t *, u8, u8, unsigned long
 /*
  * Return the current idea about the total capacity of this drive.
  */
-extern unsigned long current_capacity (ide_drive_t *drive);
+extern sector_t current_capacity (ide_drive_t *drive);
 
 /*
  * Start a reset operation for an IDE interface.