[PATCH 4/6] ide: remove hwgroup->hwif and {drive,hwif}->next

Bartlomiej Zolnierkiewicz
2008-12-13T23:41:46Z

Subject: [PATCH] ide: remove hwgroup->hwif and {drive,hwif}->next

* Add 'int port_count' field to ide_hwgroup_t to keep the track
of the number of ports in the hwgroup. Then update init_irq()
and ide_remove_port_from_hwgroup() to use it.

* Remove no longer needed hwgroup->hwif, {drive,hwif}->next,
ide_add_drive_to_hwgroup() and ide_remove_drive_from_hwgroup()
(hwgroup->drive now only denotes the currently active device
in the hwgroup).

* Update locking documentation in <linux/ide.h>.

While at it:

* Rename ->drive field in ide_hwgroup_t to ->cur_dev.

* Use __func__ in ide_timer_expiry().

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
---
drivers/ide/ide-io.c | 12 +++---
drivers/ide/ide-probe.c | 90 +++---------------------------------------------
include/linux/ide.h | 13 +-----
3 files changed, 15 insertions(+), 100 deletions(-)

Index: b/drivers/ide/ide-io.c
===================================================================
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -742,12 +742,12 @@ repeat:
* set nIEN for previous port, drives in the
* quirk_list may not like intr setups/cleanups
*/
- if (prev_port && hwgroup->drive->quirk_list == 0)
+ if (prev_port && hwgroup->cur_dev->quirk_list == 0)
prev_port->tp_ops->set_irq(prev_port, 0);

hwif->host->cur_port = hwif;
}
- hwgroup->drive = drive;
+ hwgroup->cur_dev = drive;
drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);

spin_unlock_irq(&hwgroup->lock);
@@ -913,9 +913,9 @@ void ide_timer_expiry (unsigned long dat
* Either way, we don't really want to complain about anything.
*/
} else {
- drive = hwgroup->drive;
+ drive = hwgroup->cur_dev;
if (!drive) {
- printk(KERN_ERR "ide_timer_expiry: hwgroup->drive was NULL\n");
+ printk(KERN_ERR "%s: ->cur_dev was NULL\n", __func__);
hwgroup->handler = NULL;
} else {
ide_hwif_t *hwif;
@@ -1033,7 +1033,7 @@ static void unexpected_intr(int irq, ide
* places
*
* hwif is the interface in the group currently performing
- * a command. hwgroup->drive is the drive and hwgroup->handler is
+ * a command. hwgroup->cur_dev is the drive and hwgroup->handler is
* the IRQ handler to call. As we issue a command the handlers
* step through multiple states, reassigning the handler to the
* next step in the process. Unlike a smart SCSI controller IDE
@@ -1105,7 +1105,7 @@ irqreturn_t ide_intr (int irq, void *dev
goto out;
}

- drive = hwgroup->drive;
+ drive = hwgroup->cur_dev;
if (!drive) {
/*
* This should NEVER happen, and there isn't much
Index: b/drivers/ide/ide-probe.c
===================================================================
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -918,27 +918,9 @@ static int ide_init_queue(ide_drive_t *d
return 0;
}

-static void ide_add_drive_to_hwgroup(ide_drive_t *drive)
-{
- ide_hwgroup_t *hwgroup = drive->hwif->hwgroup;
-
- spin_lock_irq(&hwgroup->lock);
- if (!hwgroup->drive) {
- /* first drive for hwgroup. */
- drive->next = drive;
- hwgroup->drive = drive;
- hwgroup->hwif = HWIF(hwgroup->drive);
- } else {
- drive->next = hwgroup->drive->next;
- hwgroup->drive->next = drive;
- }
- spin_unlock_irq(&hwgroup->lock);
-}
-
/*
* For any present drive:
* - allocate the block device queue
- * - link drive into the hwgroup
*/
static int ide_port_setup_devices(ide_hwif_t *hwif)
{
@@ -961,8 +943,6 @@ static int ide_port_setup_devices(ide_hw
}

j++;
-
- ide_add_drive_to_hwgroup(drive);
}
mutex_unlock(&ide_cfg_mtx);

@@ -978,33 +958,9 @@ void ide_remove_port_from_hwgroup(ide_hw
ide_ports[hwif->index] = NULL;

spin_lock_irq(&hwgroup->lock);
- /*
- * Remove us from the hwgroup, and free
- * the hwgroup if we were the only member
- */
- if (hwif->next == hwif) {
- BUG_ON(hwgroup->hwif != hwif);
+ /* Free the hwgroup if we were the only member. */
+ if (--hwgroup->port_count == 0)
kfree(hwgroup);
- } else {
- /* There is another interface in hwgroup.
- * Unlink us, and set hwgroup->drive and ->hwif to
- * something sane.
- */
- ide_hwif_t *g = hwgroup->hwif;
-
- while (g->next != hwif)
- g = g->next;
- g->next = hwif->next;
- if (hwgroup->hwif == hwif) {
- /* Chose a random hwif for hwgroup->hwif.
- * It's guaranteed that there are no drives
- * left in the hwgroup.
- */
- BUG_ON(hwgroup->drive != NULL);
- hwgroup->hwif = g;
- }
- BUG_ON(hwgroup->hwif == hwif);
- }
spin_unlock_irq(&hwgroup->lock);
}

@@ -1044,20 +1000,9 @@ static int init_irq (ide_hwif_t *hwif)
if (match) {
hwgroup = match->hwgroup;
hwif->hwgroup = hwgroup;
- /*
- * Link us into the hwgroup.
- * This must be done early, do ensure that unexpected_intr
- * can find the hwif and prevent irq storms.
- * No drives are attached to the new hwif, choose_drive
- * can't do anything stupid (yet).
- * Add ourself as the 2nd entry to the hwgroup->hwif
- * linked list, the first entry is the hwif that owns
- * hwgroup->handler - do not change that.
- */
+
spin_lock_irq(&hwgroup->lock);
- hwif->next = hwgroup->hwif->next;
- hwgroup->hwif->next = hwif;
- BUG_ON(hwif->next == hwif);
+ hwgroup->port_count++;
spin_unlock_irq(&hwgroup->lock);
} else {
hwgroup = kmalloc_node(sizeof(*hwgroup), GFP_KERNEL|__GFP_ZERO,
@@ -1068,7 +1013,8 @@ static int init_irq (ide_hwif_t *hwif)
spin_lock_init(&hwgroup->lock);

hwif->hwgroup = hwgroup;
- hwgroup->hwif = hwif->next = hwif;
+
+ hwgroup->port_count = 1;

init_timer(&hwgroup->timer);
hwgroup->timer.function = &ide_timer_expiry;
@@ -1191,29 +1137,6 @@ void ide_init_disk(struct gendisk *disk,

EXPORT_SYMBOL_GPL(ide_init_disk);

-static void ide_remove_drive_from_hwgroup(ide_drive_t *drive)
-{
- ide_hwgroup_t *hwgroup = drive->hwif->hwgroup;
-
- if (drive == drive->next) {
- /* special case: last drive from hwgroup. */
- BUG_ON(hwgroup->drive != drive);
- hwgroup->drive = NULL;
- } else {
- ide_drive_t *walk;
-
- walk = hwgroup->drive;
- while (walk->next != drive)
- walk = walk->next;
- walk->next = drive->next;
- if (hwgroup->drive == drive) {
- hwgroup->drive = drive->next;
- hwgroup->hwif = hwgroup->drive->hwif;
- }
- }
- BUG_ON(hwgroup->drive == drive);
-}
-
static void drive_release_dev (struct device *dev)
{
ide_drive_t *drive = container_of(dev, ide_drive_t, gendev);
@@ -1222,7 +1145,6 @@ static void drive_release_dev (struct de
ide_proc_unregister_device(drive);

spin_lock_irq(&hwgroup->lock);
- ide_remove_drive_from_hwgroup(drive);
kfree(drive->id);
drive->id = NULL;
drive->dev_flags &= ~IDE_DFLAG_PRESENT;
Index: b/include/linux/ide.h
===================================================================
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -588,7 +588,6 @@ struct ide_drive_s {
struct request_queue *queue; /* request queue */

struct request *rq; /* current request */
- struct ide_drive_s *next; /* circular list of hwgroup drives */
void *driver_data; /* extra driver data */
u16 *id; /* identification info */
#ifdef CONFIG_IDE_PROC_FS
@@ -750,7 +749,6 @@ struct ide_dma_ops {
struct ide_host;

typedef struct hwif_s {
- struct hwif_s *next; /* for linked-list in ide_hwgroup_t */
struct hwif_s *mate; /* other hwif from same PCI chip */
struct hwgroup_s *hwgroup; /* actually (ide_hwgroup_t *) */
struct proc_dir_entry *proc; /* /proc/ide/ directory entry */
@@ -874,9 +872,7 @@ typedef struct hwgroup_s {
unsigned int polling : 1;

/* current drive */
- ide_drive_t *drive;
- /* ptr to current hwif in linked-list */
- ide_hwif_t *hwif;
+ ide_drive_t *cur_dev;

/* current request */
struct request *rq;
@@ -892,6 +888,8 @@ typedef struct hwgroup_s {
int req_gen_timer;

spinlock_t lock;
+
+ int port_count;
} ide_hwgroup_t;

typedef struct ide_driver_s ide_driver_t;
@@ -1622,12 +1620,7 @@ extern struct mutex ide_cfg_mtx;
/*
* Structure locking:
*
- * ide_cfg_mtx and hwgroup->lock together protect changes to
- * ide_hwif_t->next
- * ide_drive_t->next
- *
* ide_hwgroup_t->busy: hwgroup->lock
- * ide_hwgroup_t->hwif: hwgroup->lock
* ide_hwif_t->{hwgroup,mate}: constant, no locking
* ide_drive_t->hwif: constant, no locking
*/