[044/114] mtd: change struct flchip_shared spinlock locking into mutex

From: Greg KH
Date: Tue Aug 24 2010 - 19:17:53 EST


2.6.35-stable review patch. If anyone has any objections, please let us know.

------------------

From: Stefani Seibold <stefani@xxxxxxxxxxx>

commit 8ae664184c45def51ff0b61d4bd6c6671db6cb4f upstream.

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@xxxxxxxxxxx>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>
Signed-off-by: David Woodhouse <David.Woodhouse@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
drivers/mtd/chips/cfi_cmdset_0001.c | 20 ++++++++++----------
drivers/mtd/lpddr/lpddr_cmds.c | 20 ++++++++++----------
include/linux/mtd/flashchip.h | 2 +-
3 files changed, 21 insertions(+), 21 deletions(-)

--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -717,7 +717,7 @@ static int cfi_intelext_partition_fixup(
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;
@@ -886,7 +886,7 @@ static int get_chip(struct map_info *map
*/
struct flchip_shared *shared = chip->priv;
struct flchip *contender;
- spin_lock(&shared->lock);
+ mutex_lock(&shared->lock);
contender = shared->writing;
if (contender && contender != chip) {
/*
@@ -899,7 +899,7 @@ static int get_chip(struct map_info *map
* 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);
@@ -914,7 +914,7 @@ static int get_chip(struct map_info *map
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. */
@@ -930,7 +930,7 @@ static int get_chip(struct map_info *map
* 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);
@@ -944,7 +944,7 @@ static int get_chip(struct map_info *map
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)
@@ -959,7 +959,7 @@ static void put_chip(struct map_info *ma

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;
@@ -967,7 +967,7 @@ static void put_chip(struct map_info *ma
/* 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);
@@ -985,11 +985,11 @@ static void put_chip(struct map_info *ma
* 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) {
--- a/drivers/mtd/lpddr/lpddr_cmds.c
+++ b/drivers/mtd/lpddr/lpddr_cmds.c
@@ -98,7 +98,7 @@ struct mtd_info *lpddr_cmdset(struct 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_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
* 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
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
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
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 *ma
{
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 *ma
/* 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 *ma
* 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) {
--- a/include/linux/mtd/flashchip.h
+++ b/include/linux/mtd/flashchip.h
@@ -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;
};


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