On Thu 19 Mar 16:10 PDT 2020, Mike Tipton wrote:
> Currently, if tcs_cmd_gen is called with commit=false, then
> tcs_cmd::wait is left uninitialized. Since the tcs_cmd structures passed
> to this function aren't zero-initialized, then we're left with random
> wait values. This results in waiting for completion for more commands
> than is necessary, depending on what's on the stack at the time.
>
> Removing the unnecessary if-condition fixes this, but add an explicit
> memset of the tcs_cmd structure as well to ensure predictable behavior
> if more tcs_cmd members are added in the future.
>
> Fixes: 976daac4a1c5 ("interconnect: qcom: Consolidate interconnect RPMh support")
> Signed-off-by: Mike Tipton <mdtipton@xxxxxxxxxxxxxx>
Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Regards,
Bjorn
> ---
> drivers/interconnect/qcom/bcm-voter.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/interconnect/qcom/bcm-voter.c b/drivers/interconnect/qcom/bcm-voter.c
> index 2adfde8cdf19..2a11a63e7217 100644
> --- a/drivers/interconnect/qcom/bcm-voter.c
> +++ b/drivers/interconnect/qcom/bcm-voter.c
> @@ -96,6 +96,8 @@ static inline void tcs_cmd_gen(struct tcs_cmd *cmd, u64 vote_x, u64 vote_y,
> if (!cmd)
> return;
>
> + memset(cmd, 0, sizeof(*cmd));
> +
> if (vote_x == 0 && vote_y == 0)
> valid = false;
>
> @@ -112,8 +114,7 @@ static inline void tcs_cmd_gen(struct tcs_cmd *cmd, u64 vote_x, u64 vote_y,
> * Set the wait for completion flag on command that need to be completed
> * before the next command.
> */
> - if (commit)
> - cmd->wait = true;
> + cmd->wait = commit;
> }
>
> static void tcs_list_gen(struct list_head *bcm_list, int bucket,
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
