ide: replace the global ide_lock spinlock by per-hwgroup spinlocks (v2)

Now that (almost) all host drivers have been fixed not to abuse ide_lock
and core code usage of ide_lock has been sanitized we may safely replace
ide_lock by per-hwgroup locks.

This patch is partially based on earlier patch from Ravikiran G Thirumalai.

While at it:
- don't use deprecated HWIF() and HWGROUP() macros
- update locking documentation in ide.h

v2:
Add missing spin_lock_init(&hwgroup->lock).  (Noticed by Elias Oltmanns)

Cc: Vaibhav V. Nivargi <vaibhav.nivargi@gmail.com>
Cc: Alok N. Kataria <alokk@calsoftinc.com>
Cc: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/ide/umc8672.c b/drivers/ide/umc8672.c
index 1da076e0c917..e29978cf6197 100644
--- a/drivers/ide/umc8672.c
+++ b/drivers/ide/umc8672.c
@@ -107,18 +107,21 @@ static void umc_set_speeds(u8 speeds[])
 static void umc_set_pio_mode(ide_drive_t *drive, const u8 pio)
 {
         ide_hwif_t *hwif = drive->hwif;
-        unsigned long flags;
+        ide_hwgroup_t *mate_hwgroup = hwif->mate ? hwif->mate->hwgroup : NULL;
+        unsigned long uninitialized_var(flags);
 
         printk("%s: setting umc8672 to PIO mode%d (speed %d)\n",
                 drive->name, pio, pio_to_umc[pio]);
-        spin_lock_irqsave(&ide_lock, flags);
-        if (hwif->mate && hwif->mate->hwgroup->handler) {
+        if (mate_hwgroup)
+                spin_lock_irqsave(&mate_hwgroup->lock, flags);
+        if (mate_hwgroup && mate_hwgroup->handler) {
                 printk(KERN_ERR "umc8672: other interface is busy: exiting tune_umc()\n");
         } else {
                 current_speeds[drive->name[2] - 'a'] = pio_to_umc[pio];
                 umc_set_speeds(current_speeds);
         }
-        spin_unlock_irqrestore(&ide_lock, flags);
+        if (mate_hwgroup)
+                spin_unlock_irqrestore(&mate_hwgroup->lock, flags);
 }
 
 static const struct ide_port_ops umc8672_port_ops = {