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SubjectRe: [PATCH v2] staging: rtl8188eu: remove dead code/vestigial do..while loop
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On 9/24/19 9:28 AM, Connor Kuehl wrote:
> The local variable 'bcmd_down' is always set to true almost immediately
> before the do-while's condition is checked. As a result, !bcmd_down
> evaluates to false which short circuits the logical AND operator meaning
> that the second operand is never reached and is therefore dead code.
>
> Furthermore, the do..while loop may be removed since it will always only
> execute once because 'bcmd_down' is always set to true, so the
> !bcmd_down evaluates to false and the loop exits immediately after the
> first pass.
>
> Fix this by removing the loop and its condition variables 'bcmd_down'
> and 'retry_cnts'
>
> While we're in there, also fix some checkpatch.pl suggestions regarding
> spaces around arithmetic operators like '+'
>
> Addresses-Coverity: ("Logically dead code")
>
> Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
> ---
> v1 -> v2:
> - remove the loop and its condition variable bcmd_down
> - address some non-invasive checkpatch.pl suggestions as a result of
> deleting the loop
>
> drivers/staging/rtl8188eu/hal/rtl8188e_cmd.c | 55 +++++++++-----------
> 1 file changed, 24 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/staging/rtl8188eu/hal/rtl8188e_cmd.c b/drivers/staging/rtl8188eu/hal/rtl8188e_cmd.c
> index 47352f210c0b..7646167a0b36 100644
> --- a/drivers/staging/rtl8188eu/hal/rtl8188e_cmd.c
> +++ b/drivers/staging/rtl8188eu/hal/rtl8188e_cmd.c
> @@ -47,8 +47,6 @@ static u8 _is_fw_read_cmd_down(struct adapter *adapt, u8 msgbox_num)
> ******************************************/
> static s32 FillH2CCmd_88E(struct adapter *adapt, u8 ElementID, u32 CmdLen, u8 *pCmdBuffer)
> {
> - u8 bcmd_down = false;
> - s32 retry_cnts = 100;
> u8 h2c_box_num;
> u32 msgbox_addr;
> u32 msgbox_ex_addr;
> @@ -71,39 +69,34 @@ static s32 FillH2CCmd_88E(struct adapter *adapt, u8 ElementID, u32 CmdLen, u8 *p
> goto exit;
>
> /* pay attention to if race condition happened in H2C cmd setting. */
> - do {
> - h2c_box_num = adapt->HalData->LastHMEBoxNum;
> -
> - if (!_is_fw_read_cmd_down(adapt, h2c_box_num)) {
> - DBG_88E(" fw read cmd failed...\n");
> - goto exit;
> - }
> -
> - *(u8 *)(&h2c_cmd) = ElementID;
> -
> - if (CmdLen <= 3) {
> - memcpy((u8 *)(&h2c_cmd)+1, pCmdBuffer, CmdLen);
> - } else {
> - memcpy((u8 *)(&h2c_cmd)+1, pCmdBuffer, 3);
> - ext_cmd_len = CmdLen-3;
> - memcpy((u8 *)(&h2c_cmd_ex), pCmdBuffer+3, ext_cmd_len);
> + h2c_box_num = adapt->HalData->LastHMEBoxNum;
>
> - /* Write Ext command */
> - msgbox_ex_addr = REG_HMEBOX_EXT_0 + (h2c_box_num * RTL88E_EX_MESSAGE_BOX_SIZE);
> - for (cmd_idx = 0; cmd_idx < ext_cmd_len; cmd_idx++)
> - usb_write8(adapt, msgbox_ex_addr+cmd_idx, *((u8 *)(&h2c_cmd_ex)+cmd_idx));
> - }
> - /* Write command */
> - msgbox_addr = REG_HMEBOX_0 + (h2c_box_num * RTL88E_MESSAGE_BOX_SIZE);
> - for (cmd_idx = 0; cmd_idx < RTL88E_MESSAGE_BOX_SIZE; cmd_idx++)
> - usb_write8(adapt, msgbox_addr+cmd_idx, *((u8 *)(&h2c_cmd)+cmd_idx));
> + if (!_is_fw_read_cmd_down(adapt, h2c_box_num)) {
> + DBG_88E(" fw read cmd failed...\n");
> + goto exit;
> + }
>
> - bcmd_down = true;
> + *(u8 *)(&h2c_cmd) = ElementID;
>
> - adapt->HalData->LastHMEBoxNum =
> - (h2c_box_num+1) % RTL88E_MAX_H2C_BOX_NUMS;
> + if (CmdLen <= 3) {
> + memcpy((u8 *)(&h2c_cmd) + 1, pCmdBuffer, CmdLen);
> + } else {
> + memcpy((u8 *)(&h2c_cmd) + 1, pCmdBuffer, 3);
> + ext_cmd_len = CmdLen - 3;
> + memcpy((u8 *)(&h2c_cmd_ex), pCmdBuffer + 3, ext_cmd_len);
> +
> + /* Write Ext command */
> + msgbox_ex_addr = REG_HMEBOX_EXT_0 + (h2c_box_num * RTL88E_EX_MESSAGE_BOX_SIZE);
> + for (cmd_idx = 0; cmd_idx < ext_cmd_len; cmd_idx++)
> + usb_write8(adapt, msgbox_ex_addr + cmd_idx, *((u8 *)(&h2c_cmd_ex) + cmd_idx));
> + }
> + /* Write command */
> + msgbox_addr = REG_HMEBOX_0 + (h2c_box_num * RTL88E_MESSAGE_BOX_SIZE);
> + for (cmd_idx = 0; cmd_idx < RTL88E_MESSAGE_BOX_SIZE; cmd_idx++)
> + usb_write8(adapt, msgbox_addr + cmd_idx, *((u8 *)(&h2c_cmd) + cmd_idx));
>
> - } while ((!bcmd_down) && (retry_cnts--));
> + adapt->HalData->LastHMEBoxNum =
> + (h2c_box_num + 1) % RTL88E_MAX_H2C_BOX_NUMS;
>
> ret = _SUCCESS;

Acked-by: Larry Finger <Larry.Finger@lwfinger.net>

Thanks,

Larry

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