On 2020/5/28 20:37, Dan Carpenter wrote:
> Originally this code rejected any read less than 256 bytes. There
> is no need for this artificial limit.
>
> Also I have changed the snprintf() functions to scnprintf(). The
> difference is that snprintf() returns the number of bytes which would
> have been copied if there were enough space and scnprintf() returns the
> number of bytes which were actually copied. It doesn't matter here
> because the strings are very short so they can't go over 256 bytes.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Looks good to me, thanks!
Reviewed-by: Zhou Wang <wangzhou1@xxxxxxxxxxxxx>
> ---
> drivers/crypto/hisilicon/qm.c | 18 ++++++++----------
> 1 file changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/crypto/hisilicon/qm.c b/drivers/crypto/hisilicon/qm.c
> index a781c02251980..9c0c9f500d91d 100644
> --- a/drivers/crypto/hisilicon/qm.c
> +++ b/drivers/crypto/hisilicon/qm.c
> @@ -1076,16 +1076,15 @@ static ssize_t qm_cmd_read(struct file *filp, char __user *buffer,
> if (*pos)
> return 0;
>
> - if (count < QM_DBG_READ_LEN)
> - return -ENOSPC;
> -
> - len = snprintf(buf, QM_DBG_READ_LEN, "%s\n",
> + len = scnprintf(buf, QM_DBG_READ_LEN, "%s\n",
> "Please echo help to cmd to get help information");
>
> + len = min_t(size_t, len, count);
> if (copy_to_user(buffer, buf, len))
> return -EFAULT;
>
> - return (*pos = len);
> + *pos = len;
> + return len;
> }
>
> static void *qm_ctx_alloc(struct hisi_qm *qm, size_t ctx_size,
> @@ -2710,19 +2709,18 @@ static ssize_t qm_status_read(struct file *filp, char __user *buffer,
> if (*pos)
> return 0;
>
> - if (count < QM_DBG_READ_LEN)
> - return -ENOSPC;
> -
> val = atomic_read(&qm->status.flags);
> - len = snprintf(buf, QM_DBG_READ_LEN, "%s\n", qm_s[val]);
> + len = scnprintf(buf, QM_DBG_READ_LEN, "%s\n", qm_s[val]);
> if (!len)
> return -EFAULT;
>
> + len = min_t(size_t, len, count);
> cp_len = copy_to_user(buffer, buf, len);
> if (cp_len)
> return -EFAULT;
>
> - return (*pos = len);
> + *pos = len;
> + return len;
> }
>
> static const struct file_operations qm_status_fops = {
>
