[PATCH v5 4/5] firmware: drop bit ops in favor of simple state machine

From: Daniel Wagner
Date: Fri Sep 09 2016 - 08:13:11 EST


From: Daniel Wagner <daniel.wagner@xxxxxxxxxxxx>

We track the state of the loading with bit ops. Since the state machine
has only a couple of states and they are all mutual exclusive there are
only a few simple state transition we can model this simplify.

UNKNOWN -> LOADING -> DONE | ABORTED

Cc: Ming Lei <ming.lei@xxxxxxxxxxxxx>
Cc: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Daniel Wagner <daniel.wagner@xxxxxxxxxxxx>
---
drivers/base/firmware_class.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 5e38c27..8f5838c 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -109,7 +109,7 @@ enum {

struct fw_umh {
struct completion completion;
- unsigned long status;
+ u8 status;
};

static void fw_umh_init(struct fw_umh *fw_umh)
@@ -120,7 +120,7 @@ static void fw_umh_init(struct fw_umh *fw_umh)

static int __fw_umh_check(struct fw_umh *fw_umh, unsigned long status)
{
- return test_bit(status, &fw_umh->status);
+ return fw_umh->status == status;
}

static int fw_umh_wait_timeout(struct fw_umh *fw_umh, long timeout)
@@ -129,7 +129,7 @@ static int fw_umh_wait_timeout(struct fw_umh *fw_umh, long timeout)

ret = wait_for_completion_interruptible_timeout(&fw_umh->completion,
timeout);
- if (ret != 0 && test_bit(FW_UMH_ABORTED, &fw_umh->status))
+ if (ret != 0 && READ_ONCE(fw_umh->status) == FW_UMH_ABORTED)
return -ENOENT;

return ret;
@@ -138,12 +138,10 @@ static int fw_umh_wait_timeout(struct fw_umh *fw_umh, long timeout)
static void __fw_umh_set(struct fw_umh *fw_umh,
unsigned long status)
{
- set_bit(status, &fw_umh->status);
+ WRITE_ONCE(fw_umh->status, status);

- if (status == FW_UMH_DONE || status == FW_UMH_ABORTED) {
- clear_bit(FW_UMH_LOADING, &fw_umh->status);
+ if (status == FW_UMH_DONE || status == FW_UMH_ABORTED)
complete_all(&fw_umh->completion);
- }
}

#define fw_umh_start(fw_umh) \
--
2.7.4