[PATCH] spi: amlogic-spisg: drop misleading NULL check on exdesc

[PATCH] spi: amlogic-spisg: drop misleading NULL check on exdesc

[Stepan Ionichev]

aml_spisg_setup_transfer() takes a non-NULL exdesc pointer; the
function dereferences exdesc unconditionally later in the body to
populate the SPI scatter-gather descriptors (tx_ccsg / rx_ccsg).
The sole caller, aml_spisg_transfer_one_message(), always passes a
valid pointer derived from kcalloc().

The "if (exdesc)" guard around the memset() at the start of the
function is therefore dead and misleading -- it suggests callers
may pass NULL when in fact they may not. smatch flags the
inconsistency:

  drivers/spi/spi-amlogic-spisg.c:314 aml_spisg_setup_transfer()
    error: we previously assumed 'exdesc' could be null (see line 261)

Drop the check; the unconditional memset matches the unconditional
dereferences elsewhere in the function and removes the inconsistency
that smatch reports.

No functional change.

Signed-off-by: Stepan Ionichev <sozdayvek@gmail.com>
---
 drivers/spi/spi-amlogic-spisg.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/spi/spi-amlogic-spisg.c b/drivers/spi/spi-amlogic-spisg.c
index 19c5eba41..b2a916496 100644
--- a/drivers/spi/spi-amlogic-spisg.c
+++ b/drivers/spi/spi-amlogic-spisg.c
@@ -258,8 +258,7 @@ static int aml_spisg_setup_transfer(struct spisg_device *spisg,
 	int ret;
 
 	memset(desc, 0, sizeof(*desc));
-	if (exdesc)
-		memset(exdesc, 0, sizeof(*exdesc));
+	memset(exdesc, 0, sizeof(*exdesc));
 	aml_spisg_set_speed(spisg, xfer->speed_hz);
 	xfer->effective_speed_hz = spisg->effective_speed_hz;
 
-- 
2.43.0

Re: [PATCH] spi: amlogic-spisg: drop misleading NULL check on exdesc

[Xianwei Zhao]

Hi Stepan,

On 2026/5/7 02:35, Stepan Ionichev wrote:
> aml_spisg_setup_transfer() takes a non-NULL exdesc pointer; the
> function dereferences exdesc unconditionally later in the body to
> populate the SPI scatter-gather descriptors (tx_ccsg / rx_ccsg).
> The sole caller, aml_spisg_transfer_one_message(), always passes a
> valid pointer derived from kcalloc().
> 
> The "if (exdesc)" guard around the memset() at the start of the
> function is therefore dead and misleading -- it suggests callers
> may pass NULL when in fact they may not. smatch flags the
> inconsistency:
> 
>    drivers/spi/spi-amlogic-spisg.c:314 aml_spisg_setup_transfer()
>      error: we previously assumed 'exdesc' could be null (see line 261)
> 
> Drop the check; the unconditional memset matches the unconditional
> dereferences elsewhere in the function and removes the inconsistency
> that smatch reports.
> 
> No functional change.
> 
> Signed-off-by: Stepan Ionichev<sozdayvek@gmail.com>
> ---
>   drivers/spi/spi-amlogic-spisg.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/spi/spi-amlogic-spisg.c b/drivers/spi/spi-amlogic-spisg.c
> index 19c5eba41..b2a916496 100644
> --- a/drivers/spi/spi-amlogic-spisg.c
> +++ b/drivers/spi/spi-amlogic-spisg.c
> @@ -258,8 +258,7 @@ static int aml_spisg_setup_transfer(struct spisg_device *spisg,
>          int ret;
> 
>          memset(desc, 0, sizeof(*desc));
> -       if (exdesc)
> -               memset(exdesc, 0, sizeof(*exdesc));
> +       memset(exdesc, 0, sizeof(*exdesc)); >          aml_spisg_set_speed(spisg, xfer->speed_hz);
>          xfer->effective_speed_hz = spisg->effective_speed_hz;

Reviewed-by: Xianwei Zhao <xianwei.zhao@amlogic.com>

Re: [PATCH] spi: amlogic-spisg: drop misleading NULL check on exdesc

[Mark Brown]

On Wed, 06 May 2026 23:35:12 +0500, Stepan Ionichev wrote:
> spi: amlogic-spisg: drop misleading NULL check on exdesc

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-7.2

Thanks!

[1/1] spi: amlogic-spisg: drop misleading NULL check on exdesc
      https://git.kernel.org/broonie/spi/c/54725e3049e1

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark