On Mon Jun 5, 2023 at 8:59 PM EEST, Alexander Steffen wrote:
> recv_data either returns the number of received bytes, or a negative value
> representing an error code. Adding the return value directly to the total
> number of received bytes therefore looks a little weird, since it might add
> a negative error code to a sum of bytes.
>
> The following check for size < expected usually makes the function return
> ETIME in that case, so it does not cause too many problems in practice. But
> to make the code look cleaner and because the caller might still be
> interested in the original error code, explicitly check for the presence of
> an error code and pass that through.
>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: cb5354253af2 ("[PATCH] tpm: spacing cleanups 2")
> Signed-off-by: Alexander Steffen <Alexander.Steffen@xxxxxxxxxxxx>
> ---
> drivers/char/tpm/tpm_tis_core.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 558144fa707a..aaaa136044ae 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -363,8 +363,13 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
> goto out;
> }
>
> - size += recv_data(chip, &buf[TPM_HEADER_SIZE],
> - expected - TPM_HEADER_SIZE);
> + rc = recv_data(chip, &buf[TPM_HEADER_SIZE],
> + expected - TPM_HEADER_SIZE);
> + if (rc < 0) {
> + size = rc;
> + goto out;
> + }
> + size += rc;
> if (size < expected) {
> dev_err(&chip->dev, "Unable to read remainder of result\n");
> size = -ETIME;
> --
> 2.34.1
BR, Jarkko
