diff mbox series

[v2,1/4] tpm_tis: Explicitly check for error code

Message ID 20230605175959.2131-2-Alexander.Steffen@infineon.com
State New
Headers
Series Recovery from data transfer errors for tpm_tis |

Commit Message

Alexander Steffen June 5, 2023, 5:59 p.m. UTC 
  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.

Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
---
 drivers/char/tpm/tpm_tis_core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Comments

Jarkko Sakkinen June 6, 2023, 9:09 p.m. UTC | #1 
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@vger.kernel.org
Fixes: cb5354253af2 ("[PATCH] tpm: spacing cleanups 2")

> Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
> ---
>  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
diff mbox series

Patch

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;