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| author | Daniel Wagner <daniel.wagner@bmw-carit.de> | 2016-11-17 11:00:49 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-11-29 21:28:54 +0100 |
| commit | 0430cafcc4fb632beeeab42f8817542dcf6901ce (patch) | |
| tree | 90af94390fc112eb3fd2d1e4914a2052da8d5677 /drivers/base | |
| parent | f52cc379423d61ae370aefe5344c88bc88881043 (diff) | |
| download | lwn-0430cafcc4fb632beeeab42f8817542dcf6901ce.tar.gz lwn-0430cafcc4fb632beeeab42f8817542dcf6901ce.zip | |
firmware: drop bit ops in favor of simple state machine
We track the state of the firmware loading with bit ops. Since the
state machine has only a few states and they are all mutual exclusive
there are only a few simple state transition we can model this simplify.
UNKNOWN -> LOADING -> DONE | ABORTED
Because we don't use any bit ops on fw_state::status anymore we are able
to change the data type to enum fw_status and update the function
arguments accordingly.
READ_ONCE() and WRITE_ONCE() are propably not needed because there are a
lot of load and stores around fw_st->status. But let's make it explicit
and not be sorry later.
Cc: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/firmware_class.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index 4f5105f57521..45a20dd31c25 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -112,7 +112,7 @@ static inline long firmware_loading_timeout(void) */ struct fw_state { struct completion completion; - unsigned long status; + enum fw_status status; }; static void fw_state_init(struct fw_state *fw_st) @@ -123,7 +123,7 @@ static void fw_state_init(struct fw_state *fw_st) static int __fw_state_check(struct fw_state *fw_st, enum fw_status status) { - return test_bit(status, &fw_st->status); + return fw_st->status == status; } static long __fw_state_wait_common(struct fw_state *fw_st, long timeout) @@ -132,7 +132,7 @@ static long __fw_state_wait_common(struct fw_state *fw_st, long timeout) ret = wait_for_completion_interruptible_timeout(&fw_st->completion, timeout); - if (ret != 0 && test_bit(FW_STATUS_ABORTED, &fw_st->status)) + if (ret != 0 && READ_ONCE(fw_st->status) == FW_STATUS_ABORTED) return -ENOENT; return ret; @@ -141,12 +141,10 @@ static long __fw_state_wait_common(struct fw_state *fw_st, long timeout) static void __fw_state_set(struct fw_state *fw_st, enum fw_status status) { - set_bit(status, &fw_st->status); + WRITE_ONCE(fw_st->status, status); - if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED) { - clear_bit(FW_STATUS_LOADING, &fw_st->status); + if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED) complete_all(&fw_st->completion); - } } #define fw_state_start(fw_st) \ |