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: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
index 2fadb02..97d5546 100644 (file)
--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -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) {

diff --git a/drivers/mtd/lpddr/lpddr_cmds.c b/drivers/mtd/lpddr/lpddr_cmds.c
index fece5be..04fdfcc 100644 (file)
--- 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_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) {

diff --git a/include/linux/mtd/flashchip.h b/include/linux/mtd/flashchip.h
index f43e9b4..23cc10f 100644 (file)
--- 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;
 };