2021-07-31 16:36:54

by Len Baker

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

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 <[email protected]>
Signed-off-by: Len Baker <[email protected]>
---
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/[email protected]/

v2
https://lore.kernel.org/lkml/[email protected]/

v3
https://lore.kernel.org/lkml/[email protected]/

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

2021-08-21 19:20:40

by Kalle Valo

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

Len Baker <[email protected]> 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 <[email protected]>
> Signed-off-by: Len Baker <[email protected]>

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

d816ce8744db rtw88: Remove unnecessary check code

--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/

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