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mtd: fix race in cfi_cmdset_0001 driver 

As inval_cache_and_wait_for_operation() drop and reclaim the lock
to invalidate the cache, some other thread may suspend the operation
before reaching the for(;;) loop. Therefore the loop must start with
checking the chip->state before reading status from the chip.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Acked-by: Michael Cashwell <mboards@prograde.net>
Acked-by: Stefan Bigler <stefan.bigler@keymile.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org
This commit is contained in:
Joakim Tjernlund 2011-02-07 17:07:11 +01:00 committed by David Woodhouse
parent ceabebb2bd
commit ecf3fde07c
1 changed files with 22 additions and 21 deletions
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43
drivers/mtd/chips/cfi_cmdset_0001.c
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@ -1230,10 +1230,32 @@ static int inval_cache_and_wait_for_operation(
sleep_time = chip_op_time / 2;
for (;;) {
if (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);
mutex_unlock(&chip->mutex);
schedule();
remove_wait_queue(&chip->wq, &wait);
mutex_lock(&chip->mutex);
continue;
}
status = map_read(map, cmd_adr);
if (map_word_andequal(map, status, status_OK, status_OK))
break;
if (chip->erase_suspended && chip_state == FL_ERASING) {
/* Erase suspend occured while sleep: reset timeout */
timeo = reset_timeo;
chip->erase_suspended = 0;
}
if (chip->write_suspended && chip_state == FL_WRITING) {
/* Write suspend occured while sleep: reset timeout */
timeo = reset_timeo;
chip->write_suspended = 0;
}
if (!timeo) {
map_write(map, CMD(0x70), cmd_adr);
chip->state = FL_STATUS;
@ -1257,27 +1279,6 @@ static int inval_cache_and_wait_for_operation(
timeo--;
}
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);
mutex_unlock(&chip->mutex);
schedule();
remove_wait_queue(&chip->wq, &wait);
mutex_lock(&chip->mutex);
}
if (chip->erase_suspended && chip_state == FL_ERASING) {
/* Erase suspend occured while sleep: reset timeout */
timeo = reset_timeo;
chip->erase_suspended = 0;
}
if (chip->write_suspended && chip_state == FL_WRITING) {
/* Write suspend occured while sleep: reset timeout */
timeo = reset_timeo;
chip->write_suspended = 0;
}
}
/* Done and happy. */