[PATCH v4] rtw88: Remove unnecessary check code

[PATCH v4] rtw88: Remove unnecessary check code

[Len Baker]

The rtw_pci_init_rx_ring function is only ever called with a fixed
constant or RTK_MAX_RX_DESC_NUM for the "len" argument. Since this
constant is defined as 512, the "if (len > TRX_BD_IDX_MASK)" check
can never happen (TRX_BD_IDX_MASK is defined as GENMASK(11, 0) or in
other words as 4095).

So, remove this check.

The true motivation for this patch is to silence a false Coverity
warning.

Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Len Baker <len.baker@gmx.com>
---
Changelog v1 -> v2
- Remove the macro ARRAY_SIZE from the for loop (Pkshih, Brian Norris).
- Add a new check for the len variable (Pkshih, Brian Norris).

Changelog v2 -> v3
- Change the subject of the patch.
- Remove the "if" check statement (Greg KH)
- Remove the "Fixes" tag, "Addresses-Coverity-ID" tag and Cc to stable.

Changelog v3 -> v4
- Add the "Reviewed-by: Brian Norris" tag.
- Update the commit changelog to include the true motivation for the
  patch (Brian Norris).

The previous versions can be found at:

v1
https://lore.kernel.org/lkml/20210711141634.6133-1-len.baker@gmx.com/

v2
https://lore.kernel.org/lkml/20210716155311.5570-1-len.baker@gmx.com/

v3
https://lore.kernel.org/lkml/20210718084202.5118-1-len.baker@gmx.com/

 drivers/net/wireless/realtek/rtw88/pci.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c
index e7d17ab8f113..f17e7146f20f 100644
--- a/drivers/net/wireless/realtek/rtw88/pci.c
+++ b/drivers/net/wireless/realtek/rtw88/pci.c
@@ -268,11 +268,6 @@ static int rtw_pci_init_rx_ring(struct rtw_dev *rtwdev,
 	int i, allocated;
 	int ret = 0;

-	if (len > TRX_BD_IDX_MASK) {
-		rtw_err(rtwdev, "len %d exceeds maximum RX entries\n", len);
-		return -EINVAL;
-	}
-
 	head = dma_alloc_coherent(&pdev->dev, ring_sz, &dma, GFP_KERNEL);
 	if (!head) {
 		rtw_err(rtwdev, "failed to allocate rx ring\n");
--
2.25.1

Re: [PATCH v4] rtw88: Remove unnecessary check code

[Kalle Valo]

Len Baker <len.baker@gmx.com> wrote:

> The rtw_pci_init_rx_ring function is only ever called with a fixed
> constant or RTK_MAX_RX_DESC_NUM for the "len" argument. Since this
> constant is defined as 512, the "if (len > TRX_BD_IDX_MASK)" check
> can never happen (TRX_BD_IDX_MASK is defined as GENMASK(11, 0) or in
> other words as 4095).
> 
> So, remove this check.
> 
> The true motivation for this patch is to silence a false Coverity
> warning.
> 
> Reviewed-by: Brian Norris <briannorris@chromium.org>
> Signed-off-by: Len Baker <len.baker@gmx.com>

Patch applied to wireless-drivers-next.git, thanks.

d816ce8744db rtw88: Remove unnecessary check code

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20210731163546.10753-1-len.baker@gmx.com/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches