Fix a huge latency problem in the MTD CFI and LPDDR flash drivers.

index 9253043..62f3ea9 100644
@@ -725,8 +725,7 @@ static int cfi_intelext_partition_fixup(struct mtd_info *mtd,
 				/* those should be reset too since
 				   they create memory references. */
 				init_waitqueue_head(&chip->wq);
-				spin_lock_init(&chip->_spinlock);
-				chip->mutex = &chip->_spinlock;
+				mutex_init(&chip->mutex);
 				chip++;
 			}
 		}

@@ -772,9 +771,9 @@ static int chip_ready (struct map_info *map, struct flchip *chip, unsigned long
 			if (chip->priv && map_word_andequal(map, status, status_PWS, status_PWS))
 				break;
 
-			spin_unlock(chip->mutex);
+			mutex_unlock(&chip->mutex);
 			cfi_udelay(1);
-			spin_lock(chip->mutex);
+			mutex_lock(&chip->mutex);
 			/* Someone else might have been playing with it. */
 			return -EAGAIN;
 		}

@@ -821,9 +820,9 @@ static int chip_ready (struct map_info *map, struct flchip *chip, unsigned long
 				return -EIO;
 			}
 
-			spin_unlock(chip->mutex);
+			mutex_unlock(&chip->mutex);
 			cfi_udelay(1);
-			spin_lock(chip->mutex);
+			mutex_lock(&chip->mutex);
 			/* Nobody will touch it while it's in state FL_ERASE_SUSPENDING.
 			   So we can just loop here. */
 		}

@@ -850,10 +849,10 @@ static int chip_ready (struct map_info *map, struct flchip *chip, unsigned long
 	sleep:
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		add_wait_queue(&chip->wq, &wait);
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 		schedule();
 		remove_wait_queue(&chip->wq, &wait);
-		spin_lock(chip->mutex);
+		mutex_lock(&chip->mutex);
 		return -EAGAIN;
 	}
 }

@@ -899,20 +898,20 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr
 			 * it'll happily send us to sleep.  In any case, when
 			 * get_chip returns success we're clear to go ahead.
 			 */
-			ret = spin_trylock(contender->mutex);
+			ret = mutex_trylock(&contender->mutex);
 			spin_unlock(&shared->lock);
 			if (!ret)
 				goto retry;
-			spin_unlock(chip->mutex);
+			mutex_unlock(&chip->mutex);
 			ret = chip_ready(map, contender, contender->start, mode);
-			spin_lock(chip->mutex);
+			mutex_lock(&chip->mutex);
 
 			if (ret == -EAGAIN) {
-				spin_unlock(contender->mutex);
+				mutex_unlock(&contender->mutex);
 				goto retry;
 			}
 			if (ret) {
-				spin_unlock(contender->mutex);
+				mutex_unlock(&contender->mutex);
 				return ret;
 			}
 			spin_lock(&shared->lock);

@@ -921,10 +920,10 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr
 			 * in FL_SYNCING state. Put contender and retry. */
 			if (chip->state == FL_SYNCING) {
 				put_chip(map, contender, contender->start);
-				spin_unlock(contender->mutex);
+				mutex_unlock(&contender->mutex);
 				goto retry;
 			}
-			spin_unlock(contender->mutex);
+			mutex_unlock(&contender->mutex);
 		}
 
 		/* Check if we already have suspended erase

@@ -934,10 +933,10 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr
 			spin_unlock(&shared->lock);
 			set_current_state(TASK_UNINTERRUPTIBLE);
 			add_wait_queue(&chip->wq, &wait);
-			spin_unlock(chip->mutex);
+			mutex_unlock(&chip->mutex);
 			schedule();
 			remove_wait_queue(&chip->wq, &wait);
-			spin_lock(chip->mutex);
+			mutex_lock(&chip->mutex);
 			goto retry;
 		}
 

@@ -967,12 +966,12 @@ static void put_chip(struct map_info *map, struct flchip *chip, unsigned long ad
 			if (shared->writing && shared->writing != chip) {
 				/* give back ownership to who we loaned it from */
 				struct flchip *loaner = shared->writing;
-				spin_lock(loaner->mutex);
+				mutex_lock(&loaner->mutex);
 				spin_unlock(&shared->lock);
-				spin_unlock(chip->mutex);
+				mutex_unlock(&chip->mutex);
 				put_chip(map, loaner, loaner->start);
-				spin_lock(chip->mutex);
-				spin_unlock(loaner->mutex);
+				mutex_lock(&chip->mutex);
+				mutex_unlock(&loaner->mutex);
 				wake_up(&chip->wq);
 				return;
 			}

@@ -1142,7 +1141,7 @@ static int __xipram xip_wait_for_operation(
 			(void) map_read(map, adr);
 			xip_iprefetch();
 			local_irq_enable();
-			spin_unlock(chip->mutex);
+			mutex_unlock(&chip->mutex);
 			xip_iprefetch();
 			cond_resched();
 

@@ -1152,15 +1151,15 @@ static int __xipram xip_wait_for_operation(
 			 * a suspended erase state.  If so let's wait
 			 * until it's done.
 			 */
-			spin_lock(chip->mutex);
+			mutex_lock(&chip->mutex);
 			while (chip->state != newstate) {
 				DECLARE_WAITQUEUE(wait, current);
 				set_current_state(TASK_UNINTERRUPTIBLE);
 				add_wait_queue(&chip->wq, &wait);
-				spin_unlock(chip->mutex);
+				mutex_unlock(&chip->mutex);
 				schedule();
 				remove_wait_queue(&chip->wq, &wait);
-				spin_lock(chip->mutex);
+				mutex_lock(&chip->mutex);
 			}
 			/* Disallow XIP again */
 			local_irq_disable();

@@ -1216,10 +1215,10 @@ static int inval_cache_and_wait_for_operation(
 	int chip_state = chip->state;
 	unsigned int timeo, sleep_time, reset_timeo;
 
-	spin_unlock(chip->mutex);
+	mutex_unlock(&chip->mutex);
 	if (inval_len)
 		INVALIDATE_CACHED_RANGE(map, inval_adr, inval_len);
-	spin_lock(chip->mutex);
+	mutex_lock(&chip->mutex);
 
 	timeo = chip_op_time_max;
 	if (!timeo)

@@ -1239,7 +1238,7 @@ static int inval_cache_and_wait_for_operation(
 		}
 
 		/* OK Still waiting. Drop the lock, wait a while and retry. */
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 		if (sleep_time >= 1000000/HZ) {
 			/*
 			 * Half of the normal delay still remaining

@@ -1254,17 +1253,17 @@ static int inval_cache_and_wait_for_operation(
 			cond_resched();
 			timeo--;
 		}
-		spin_lock(chip->mutex);
+		mutex_lock(&chip->mutex);
 
 		while (chip->state != chip_state) {
 			/* Someone's suspended the operation: sleep */
 			DECLARE_WAITQUEUE(wait, current);
 			set_current_state(TASK_UNINTERRUPTIBLE);
 			add_wait_queue(&chip->wq, &wait);
-			spin_unlock(chip->mutex);
+			mutex_unlock(&chip->mutex);
 			schedule();
 			remove_wait_queue(&chip->wq, &wait);
-			spin_lock(chip->mutex);
+			mutex_lock(&chip->mutex);
 		}
 		if (chip->erase_suspended && chip_state == FL_ERASING)  {
 			/* Erase suspend occured while sleep: reset timeout */

@@ -1300,7 +1299,7 @@ static int do_point_onechip (struct map_info *map, struct flchip *chip, loff_t a
 	/* Ensure cmd read/writes are aligned. */
 	cmd_addr = adr & ~(map_bankwidth(map)-1);
 
-	spin_lock(chip->mutex);
+	mutex_lock(&chip->mutex);
 
 	ret = get_chip(map, chip, cmd_addr, FL_POINT);
 

@@ -1311,7 +1310,7 @@ static int do_point_onechip (struct map_info *map, struct flchip *chip, loff_t a
 		chip->state = FL_POINT;
 		chip->ref_point_counter++;
 	}
-	spin_unlock(chip->mutex);
+	mutex_unlock(&chip->mutex);
 
 	return ret;
 }

@@ -1396,7 +1395,7 @@ static void cfi_intelext_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
 		else
 			thislen = len;
 
-		spin_lock(chip->mutex);
+		mutex_lock(&chip->mutex);
 		if (chip->state == FL_POINT) {
 			chip->ref_point_counter--;
 			if(chip->ref_point_counter == 0)

@@ -1405,7 +1404,7 @@ static void cfi_intelext_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
 			printk(KERN_ERR "%s: Warning: unpoint called on non pointed region\n", map->name); /* Should this give an error? */
 
 		put_chip(map, chip, chip->start);
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 
 		len -= thislen;
 		ofs = 0;

@@ -1424,10 +1423,10 @@ static inline int do_read_onechip(struct map_info *map, struct flchip *chip, lof
 	/* Ensure cmd read/writes are aligned. */
 	cmd_addr = adr & ~(map_bankwidth(map)-1);
 
-	spin_lock(chip->mutex);
+	mutex_lock(&chip->mutex);
 	ret = get_chip(map, chip, cmd_addr, FL_READY);
 	if (ret) {
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 		return ret;
 	}
 

@@ -1441,7 +1440,7 @@ static inline int do_read_onechip(struct map_info *map, struct flchip *chip, lof
 
 	put_chip(map, chip, cmd_addr);
 
-	spin_unlock(chip->mutex);
+	mutex_unlock(&chip->mutex);
 	return 0;
 }
 

@@ -1504,10 +1503,10 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,
 		return -EINVAL;
 	}
 
-	spin_lock(chip->mutex);
+	mutex_lock(&chip->mutex);
 	ret = get_chip(map, chip, adr, mode);
 	if (ret) {
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 		return ret;
 	}
 

@@ -1553,7 +1552,7 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,
 
 	xip_enable(map, chip, adr);
  out:	put_chip(map, chip, adr);
-	spin_unlock(chip->mutex);
+	mutex_unlock(&chip->mutex);
 	return ret;
 }
 

@@ -1662,10 +1661,10 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
 	/* Let's determine this according to the interleave only once */
 	write_cmd = (cfi->cfiq->P_ID != 0x0200) ? CMD(0xe8) : CMD(0xe9);
 
-	spin_lock(chip->mutex);
+	mutex_lock(&chip->mutex);
 	ret = get_chip(map, chip, cmd_adr, FL_WRITING);
 	if (ret) {
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 		return ret;
 	}
 

@@ -1796,7 +1795,7 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
 
 	xip_enable(map, chip, cmd_adr);
  out:	put_chip(map, chip, cmd_adr);
-	spin_unlock(chip->mutex);
+	mutex_unlock(&chip->mutex);
 	return ret;
 }
 

@@ -1875,10 +1874,10 @@ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
 	adr += chip->start;
 
  retry:
-	spin_lock(chip->mutex);
+	mutex_lock(&chip->mutex);
 	ret = get_chip(map, chip, adr, FL_ERASING);
 	if (ret) {
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 		return ret;
 	}
 

@@ -1934,7 +1933,7 @@ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
 		} else if (chipstatus & 0x20 && retries--) {
 			printk(KERN_DEBUG "block erase failed at 0x%08lx: status 0x%lx. Retrying...\n", adr, chipstatus);
 			put_chip(map, chip, adr);
-			spin_unlock(chip->mutex);
+			mutex_unlock(&chip->mutex);
 			goto retry;
 		} else {
 			printk(KERN_ERR "%s: block erase failed at 0x%08lx (status 0x%lx)\n", map->name, adr, chipstatus);

@@ -1946,7 +1945,7 @@ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
 
 	xip_enable(map, chip, adr);
  out:	put_chip(map, chip, adr);
-	spin_unlock(chip->mutex);
+	mutex_unlock(&chip->mutex);
 	return ret;
 }
 

@@ -1979,7 +1978,7 @@ static void cfi_intelext_sync (struct mtd_info *mtd)
 	for (i=0; !ret && i<cfi->numchips; i++) {
 		chip = &cfi->chips[i];
 
-		spin_lock(chip->mutex);
+		mutex_lock(&chip->mutex);
 		ret = get_chip(map, chip, chip->start, FL_SYNCING);
 
 		if (!ret) {

@@ -1990,7 +1989,7 @@ static void cfi_intelext_sync (struct mtd_info *mtd)
 			 * with the chip now anyway.
 			 */
 		}
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 	}
 
 	/* Unlock the chips again */

@@ -1998,14 +1997,14 @@ static void cfi_intelext_sync (struct mtd_info *mtd)
 	for (i--; i >=0; i--) {
 		chip = &cfi->chips[i];
 
-		spin_lock(chip->mutex);
+		mutex_lock(&chip->mutex);
 
 		if (chip->state == FL_SYNCING) {
 			chip->state = chip->oldstate;
 			chip->oldstate = FL_READY;
 			wake_up(&chip->wq);
 		}
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 	}
 }
 

@@ -2051,10 +2050,10 @@ static int __xipram do_xxlock_oneblock(struct map_info *map, struct flchip *chip
 
 	adr += chip->start;
 
-	spin_lock(chip->mutex);
+	mutex_lock(&chip->mutex);
 	ret = get_chip(map, chip, adr, FL_LOCKING);
 	if (ret) {
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 		return ret;
 	}
 

@@ -2088,7 +2087,7 @@ static int __xipram do_xxlock_oneblock(struct map_info *map, struct flchip *chip
 
 	xip_enable(map, chip, adr);
 out:	put_chip(map, chip, adr);
-	spin_unlock(chip->mutex);
+	mutex_unlock(&chip->mutex);
 	return ret;
 }
 

@@ -2153,10 +2152,10 @@ do_otp_read(struct map_info *map, struct flchip *chip, u_long offset,
 	struct cfi_private *cfi = map->fldrv_priv;
 	int ret;
 
-	spin_lock(chip->mutex);
+	mutex_lock(&chip->mutex);
 	ret = get_chip(map, chip, chip->start, FL_JEDEC_QUERY);
 	if (ret) {
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 		return ret;
 	}
 

@@ -2175,7 +2174,7 @@ do_otp_read(struct map_info *map, struct flchip *chip, u_long offset,
 	INVALIDATE_CACHED_RANGE(map, chip->start + offset, size);
 
 	put_chip(map, chip, chip->start);
-	spin_unlock(chip->mutex);
+	mutex_unlock(&chip->mutex);
 	return 0;
 }
 

@@ -2450,7 +2449,7 @@ static int cfi_intelext_suspend(struct mtd_info *mtd)
 	for (i=0; !ret && i<cfi->numchips; i++) {
 		chip = &cfi->chips[i];
 
-		spin_lock(chip->mutex);
+		mutex_lock(&chip->mutex);
 
 		switch (chip->state) {
 		case FL_READY:

@@ -2482,7 +2481,7 @@ static int cfi_intelext_suspend(struct mtd_info *mtd)
 		case FL_PM_SUSPENDED:
 			break;
 		}
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 	}
 
 	/* Unlock the chips again */

@@ -2491,7 +2490,7 @@ static int cfi_intelext_suspend(struct mtd_info *mtd)
 		for (i--; i >=0; i--) {
 			chip = &cfi->chips[i];
 
-			spin_lock(chip->mutex);
+			mutex_lock(&chip->mutex);
 
 			if (chip->state == FL_PM_SUSPENDED) {
 				/* No need to force it into a known state here,

@@ -2501,7 +2500,7 @@ static int cfi_intelext_suspend(struct mtd_info *mtd)
 				chip->oldstate = FL_READY;
 				wake_up(&chip->wq);
 			}
-			spin_unlock(chip->mutex);
+			mutex_unlock(&chip->mutex);
 		}
 	}
 

@@ -2542,7 +2541,7 @@ static void cfi_intelext_resume(struct mtd_info *mtd)
 
 		chip = &cfi->chips[i];
 
-		spin_lock(chip->mutex);
+		mutex_lock(&chip->mutex);
 
 		/* Go to known state. Chip may have been power cycled */
 		if (chip->state == FL_PM_SUSPENDED) {

@@ -2551,7 +2550,7 @@ static void cfi_intelext_resume(struct mtd_info *mtd)
 			wake_up(&chip->wq);
 		}
 
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 	}
 
 	if ((mtd->flags & MTD_POWERUP_LOCK)

@@ -2571,14 +2570,14 @@ static int cfi_intelext_reset(struct mtd_info *mtd)
 		/* force the completion of any ongoing operation
 		   and switch to array mode so any bootloader in
 		   flash is accessible for soft reboot. */
-		spin_lock(chip->mutex);
+		mutex_lock(&chip->mutex);
 		ret = get_chip(map, chip, chip->start, FL_SHUTDOWN);
 		if (!ret) {
 			map_write(map, CMD(0xff), chip->start);
 			chip->state = FL_SHUTDOWN;
 			put_chip(map, chip, chip->start);
 		}
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 	}
 
 	return 0;

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index 57e0e4e..d180649 100644
@@ -58,10 +58,10 @@ static int fwh_xxlock_oneblock(struct map_info *map, struct flchip *chip,
 	 * to flash memory - that means that we don't have to check status
 	 * and timeout.
 	 */
-	spin_lock(chip->mutex);
+	mutex_lock(&chip->mutex);
 	ret = get_chip(map, chip, adr, FL_LOCKING);
 	if (ret) {
-		spin_unlock(chip->mutex);
+		mutex_unlock(&chip->mutex);
 		return ret;
 	}
 

@@ -72,7 +72,7 @@ static int fwh_xxlock_oneblock(struct map_info *map, struct flchip *chip,
 	/* Done and happy. */
 	chip->state = chip->oldstate;
 	put_chip(map, chip, adr);
-	spin_unlock(chip->mutex);
+	mutex_unlock(&chip->mutex);
 	return 0;
 }
 

index e2dc964..fcc1bc0 100644
@@ -155,8 +155,7 @@ static struct cfi_private *genprobe_ident_chips(struct map_info *map, struct chi
 			pchip->start = (i << cfi.chipshift);
 			pchip->state = FL_READY;
 			init_waitqueue_head(&pchip->wq);
-			spin_lock_init(&pchip->_spinlock);
-			pchip->mutex = &pchip->_spinlock;
+			mutex_init(&pchip->mutex);
 		}
 	}
 

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index d0bf422..f43e9b4 100644
@@ -15,6 +15,7 @@
  * has asm/spinlock.h, or 2.4, which has linux/spinlock.h
  */
 #include <linux/sched.h>
+#include <linux/mutex.h>
 
 typedef enum {
 	FL_READY,

@@ -74,8 +75,7 @@ struct flchip {
 	unsigned int erase_suspended:1;
 	unsigned long in_progress_block_addr;
 
-	spinlock_t *mutex;
-	spinlock_t _spinlock; /* We do it like this because sometimes they'll be shared. */
+	struct mutex mutex;
 	wait_queue_head_t wq; /* Wait on here when we're waiting for the chip
 			     to be ready */
 	int word_write_time;