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mtd: change struct flchip_shared spinlock locking into mutex
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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: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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Stefani Seibold authored and David Woodhouse committed Aug 6, 2010
1 parent b8664b3 commit 8ae6641
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Showing 3 changed files with 21 additions and 21 deletions.
20 changes: 10 additions & 10 deletions drivers/mtd/chips/cfi_cmdset_0001.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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) {
/*
Expand All @@ -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);
Expand All @@ -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. */
Expand All @@ -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);
Expand All @@ -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)
Expand All @@ -962,15 +962,15 @@ 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;
if (shared->writing && shared->writing != chip) {
/* 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);
Expand All @@ -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) {
Expand Down
20 changes: 10 additions & 10 deletions drivers/mtd/lpddr/lpddr_cmds.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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) {
/*
Expand All @@ -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);
Expand All @@ -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. */
Expand All @@ -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);
Expand All @@ -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);
Expand Down Expand Up @@ -348,15 +348,15 @@ 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;
if (shared->writing && shared->writing != 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);
Expand All @@ -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) {
Expand Down
2 changes: 1 addition & 1 deletion include/linux/mtd/flashchip.h
Original file line number Diff line number Diff line change
Expand Up @@ -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;
};
Expand Down

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