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Commit 8ae66418 authored by Stefani Seibold's avatar Stefani Seibold Committed by David Woodhouse
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mtd: change struct flchip_shared spinlock locking into mutex 



This patch prevent to schedule while atomic by changing the
flchip_shared spinlock into a mutex. This should be save since no atomic
path will use this lock.

It was suggested by Arnd Bergmann and Vasiliy Kulikov.

Signed-off-by: default avatarStefani Seibold <stefani@seibold.net>
Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent b8664b37

drivers/mtd/chips/cfi_cmdset_0001.c

+10 −10
Original line number Diff line number Diff line
@@ -720,7 +720,7 @@ static int cfi_intelext_partition_fixup(struct mtd_info *mtd, 
		chip = &newcfi->chips[0];

		for (i = 0; i < cfi->numchips; i++) {

			shared[i].writing = shared[i].erasing = NULL;

			spin_lock_init(&shared[i].lock);

			mutex_init(&shared[i].lock);

			for (j = 0; j < numparts; j++) {

				*chip = cfi->chips[i];

				chip->start += j << partshift;
@@ -889,7 +889,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr 
		 */

		struct flchip_shared *shared = chip->priv;

		struct flchip *contender;

		spin_lock(&shared->lock);

		mutex_lock(&shared->lock);

		contender = shared->writing;

		if (contender && contender != chip) {

			/*
@@ -902,7 +902,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr 
			 * get_chip returns success we're clear to go ahead.

			 */

			ret = mutex_trylock(&contender->mutex);

			spin_unlock(&shared->lock);

			mutex_unlock(&shared->lock);

			if (!ret)

				goto retry;

			mutex_unlock(&chip->mutex);
@@ -917,7 +917,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr 
				mutex_unlock(&contender->mutex);

				return ret;

			}

			spin_lock(&shared->lock);

			mutex_lock(&shared->lock);



			/* We should not own chip if it is already

			 * in FL_SYNCING state. Put contender and retry. */
@@ -933,7 +933,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr 
		 * on this chip. Sleep. */

		if (mode == FL_ERASING && shared->erasing

		    && shared->erasing->oldstate == FL_ERASING) {

			spin_unlock(&shared->lock);

			mutex_unlock(&shared->lock);

			set_current_state(TASK_UNINTERRUPTIBLE);

			add_wait_queue(&chip->wq, &wait);

			mutex_unlock(&chip->mutex);
@@ -947,7 +947,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr 
		shared->writing = chip;

		if (mode == FL_ERASING)

			shared->erasing = chip;

		spin_unlock(&shared->lock);

		mutex_unlock(&shared->lock);

	}

	ret = chip_ready(map, chip, adr, mode);

	if (ret == -EAGAIN)
@@ -962,7 +962,7 @@ static void put_chip(struct map_info *map, struct flchip *chip, unsigned long ad 


	if (chip->priv) {

		struct flchip_shared *shared = chip->priv;

		spin_lock(&shared->lock);

		mutex_lock(&shared->lock);

		if (shared->writing == chip && chip->oldstate == FL_READY) {

			/* We own the ability to write, but we're done */

			shared->writing = shared->erasing;
@@ -970,7 +970,7 @@ static void put_chip(struct map_info *map, struct flchip *chip, unsigned long ad 
				/* give back ownership to who we loaned it from */

				struct flchip *loaner = shared->writing;

				mutex_lock(&loaner->mutex);

				spin_unlock(&shared->lock);

				mutex_unlock(&shared->lock);

				mutex_unlock(&chip->mutex);

				put_chip(map, loaner, loaner->start);

				mutex_lock(&chip->mutex);
@@ -988,11 +988,11 @@ static void put_chip(struct map_info *map, struct flchip *chip, unsigned long ad 
			 * Don't let the switch below mess things up since

			 * we don't have ownership to resume anything.

			 */

			spin_unlock(&shared->lock);

			mutex_unlock(&shared->lock);

			wake_up(&chip->wq);

			return;

		}

		spin_unlock(&shared->lock);

		mutex_unlock(&shared->lock);

	}



	switch(chip->oldstate) {

drivers/mtd/lpddr/lpddr_cmds.c

+10 −10
Original line number Diff line number Diff line
@@ -98,7 +98,7 @@ struct mtd_info *lpddr_cmdset(struct map_info *map) 
	numchips = lpddr->numchips / lpddr->qinfo->HWPartsNum;

	for (i = 0; i < numchips; i++) {

		shared[i].writing = shared[i].erasing = NULL;

		spin_lock_init(&shared[i].lock);

		mutex_init(&shared[i].lock);

		for (j = 0; j < lpddr->qinfo->HWPartsNum; j++) {

			*chip = lpddr->chips[i];

			chip->start += j << lpddr->chipshift;
@@ -217,7 +217,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, int mode) 
		 */

		struct flchip_shared *shared = chip->priv;

		struct flchip *contender;

		spin_lock(&shared->lock);

		mutex_lock(&shared->lock);

		contender = shared->writing;

		if (contender && contender != chip) {

			/*
@@ -230,7 +230,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, int mode) 
			 * get_chip returns success we're clear to go ahead.

			 */

			ret = mutex_trylock(&contender->mutex);

			spin_unlock(&shared->lock);

			mutex_unlock(&shared->lock);

			if (!ret)

				goto retry;

			mutex_unlock(&chip->mutex);
@@ -245,7 +245,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, int mode) 
				mutex_unlock(&contender->mutex);

				return ret;

			}

			spin_lock(&shared->lock);

			mutex_lock(&shared->lock);



			/* We should not own chip if it is already in FL_SYNCING

			 * state. Put contender and retry. */
@@ -261,7 +261,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, int mode) 
		   Must sleep in such a case. */

		if (mode == FL_ERASING && shared->erasing

		    && shared->erasing->oldstate == FL_ERASING) {

			spin_unlock(&shared->lock);

			mutex_unlock(&shared->lock);

			set_current_state(TASK_UNINTERRUPTIBLE);

			add_wait_queue(&chip->wq, &wait);

			mutex_unlock(&chip->mutex);
@@ -275,7 +275,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, int mode) 
		shared->writing = chip;

		if (mode == FL_ERASING)

			shared->erasing = chip;

		spin_unlock(&shared->lock);

		mutex_unlock(&shared->lock);

	}



	ret = chip_ready(map, chip, mode);
@@ -348,7 +348,7 @@ static void put_chip(struct map_info *map, struct flchip *chip) 
{

	if (chip->priv) {

		struct flchip_shared *shared = chip->priv;

		spin_lock(&shared->lock);

		mutex_lock(&shared->lock);

		if (shared->writing == chip && chip->oldstate == FL_READY) {

			/* We own the ability to write, but we're done */

			shared->writing = shared->erasing;
@@ -356,7 +356,7 @@ static void put_chip(struct map_info *map, struct flchip *chip) 
				/* give back the ownership */

				struct flchip *loaner = shared->writing;

				mutex_lock(&loaner->mutex);

				spin_unlock(&shared->lock);

				mutex_unlock(&shared->lock);

				mutex_unlock(&chip->mutex);

				put_chip(map, loaner);

				mutex_lock(&chip->mutex);
@@ -374,11 +374,11 @@ static void put_chip(struct map_info *map, struct flchip *chip) 
			 * Don't let the switch below mess things up since

			 * we don't have ownership to resume anything.

			 */

			spin_unlock(&shared->lock);

			mutex_unlock(&shared->lock);

			wake_up(&chip->wq);

			return;

		}

		spin_unlock(&shared->lock);

		mutex_unlock(&shared->lock);

	}



	switch (chip->oldstate) {

include/linux/mtd/flashchip.h

+1 −1
Original line number Diff line number Diff line
@@ -92,7 +92,7 @@ struct flchip { 
/* This is used to handle contention on write/erase operations

   between partitions of the same physical chip. */

struct flchip_shared {

	spinlock_t lock;

	struct mutex lock;

	struct flchip *writing;

	struct flchip *erasing;

};