On Thu, Jun 19, 2025 at 05:37:07AM -0700, Chelsy Ratnawat wrote:
> Replace calls to scnprintf() with sysfs_emit() and sysfs_emit_at() in
> sysfs show functions. These helpers are preferred in sysfs callbacks
> because they automatically handle buffer sizing (PAGE_SIZE) and
> improve safety and readability.
>
> Signed-off-by: Chelsy Ratnawat <chelsyratnawat2...@gmail.com>
Some comments about the commit message.
Don't use "readability" as an argument as it is something that we cannot
measure, and thus useless documentation.
I neither don't understand "PAGE_SIZE" in the parentheses, or how it
"connects" to the sentence. And what do you mean exactly by safety?
Off-topic'ish:
In the Jargon world, safety is actually different than security :-)
Commercial airline planes have great safety (through redundancy)
and not as great (information) security. Just to reflect why
"safety" is neither an argument ...
> ---
> drivers/char/tpm/tpm_ppi.c | 26 +++++++++++++-------------
> 1 file changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
> index bc7b1b4501b3..421c6264bac9 100644
> --- a/drivers/char/tpm/tpm_ppi.c
> +++ b/drivers/char/tpm/tpm_ppi.c
> @@ -52,7 +52,7 @@ static ssize_t tpm_show_ppi_version(struct device *dev,
> {
> struct tpm_chip *chip = to_tpm_chip(dev);
>
> - return scnprintf(buf, PAGE_SIZE, "%s\n", chip->ppi_version);
> + return sysfs_emit(buf, "%s\n", chip->ppi_version);
> }
>
> static ssize_t tpm_show_ppi_request(struct device *dev,
> @@ -87,11 +87,11 @@ static ssize_t tpm_show_ppi_request(struct device *dev,
> else {
> req = obj->package.elements[1].integer.value;
> if (tpm_ppi_req_has_parameter(req))
> - size = scnprintf(buf, PAGE_SIZE,
> + size = sysfs_emit(buf,
> "%llu %llu\n", req,
> obj->package.elements[2].integer.value);
> else
> - size = scnprintf(buf, PAGE_SIZE,
> + size = sysfs_emit(buf,
> "%llu\n", req);
> }
> } else if (obj->package.count == 2 &&
> @@ -100,7 +100,7 @@ static ssize_t tpm_show_ppi_request(struct device *dev,
> if (obj->package.elements[0].integer.value)
> size = -EFAULT;
> else
> - size = scnprintf(buf, PAGE_SIZE, "%llu\n",
> + size = sysfs_emit(buf, "%llu\n",
> obj->package.elements[1].integer.value);
> }
>
> @@ -211,9 +211,9 @@ static ssize_t tpm_show_ppi_transition_action(struct
> device *dev,
> }
>
> if (ret < ARRAY_SIZE(info) - 1)
> - status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret, info[ret]);
> + status = sysfs_emit(buf, "%d: %s\n", ret, info[ret]);
> else
> - status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret,
> + status = sysfs_emit(buf, "%d: %s\n", ret,
> info[ARRAY_SIZE(info)-1]);
> return status;
> }
> @@ -255,22 +255,22 @@ static ssize_t tpm_show_ppi_response(struct device *dev,
> res = ret_obj[2].integer.value;
> if (req) {
> if (res == 0)
> - status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
> + status = sysfs_emit(buf, "%llu %s\n", req,
> "0: Success");
> else if (res == 0xFFFFFFF0)
> - status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
> + status = sysfs_emit(buf, "%llu %s\n", req,
> "0xFFFFFFF0: User Abort");
> else if (res == 0xFFFFFFF1)
> - status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
> + status = sysfs_emit(buf, "%llu %s\n", req,
> "0xFFFFFFF1: BIOS Failure");
> else if (res >= 1 && res <= 0x00000FFF)
> - status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
> + status = sysfs_emit(buf, "%llu %llu: %s\n",
> req, res, "Corresponding TPM error");
> else
> - status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
> + status = sysfs_emit(buf, "%llu %llu: %s\n",
> req, res, "Error");
> } else {
> - status = scnprintf(buf, PAGE_SIZE, "%llu: %s\n",
> + status = sysfs_emit(buf, "%llu: %s\n",
> req, "No Recent Request");
> }
>
> @@ -314,7 +314,7 @@ static ssize_t show_ppi_operations(acpi_handle
> dev_handle, char *buf, u32 start,
> }
>
> if (ret > 0 && ret < ARRAY_SIZE(info))
> - str += scnprintf(str, PAGE_SIZE, "%d %d: %s\n",
> + str += sysfs_emit_at(str, "%d %d: %s\n",
> i, ret, info[ret]);
> }
>
> --
> 2.47.1
>
BR, Jarkko
