RE: [PATCH net] octeontx2-af: poll for TX link credits before link mode change

[Jagielski, Jedrzej]

From: Ratheesh Kannoth <rkannoth@xxxxxxxxxxx> 
Sent: Wednesday, August 19, 2026 6:39 AM

>On 2026-08-18 at 13:08:48, Jagielski, Jedrzej (jedrzej.jagielski@xxxxxxxxx) wrote:
>> From: Ratheesh Kannoth <rkannoth@xxxxxxxxxxx>
>> Sent: Tuesday, August 18, 2026 5:37 AM
>>
>> >+int rvu_nix_tl1_xoff_wait_for_link_credits(struct rvu *rvu, u16 pcifunc)
>> >+{
>> >+	int link, blkaddr, count = 1000;
>>
>> count can be declared inside the loop as it's not used outside
>> same for regval
>historically the Linux kernel required declaring all variables at the beginning of a function or block.
>
>>
>> moreover defs instead of magic is always better choice
>AFAIK, this is not a magic number but a counter.
>Could you show me the Kernel coding guidilines which mandates this ?

naah, probably i cant but what im saying is that what imho is worth
not mandatory
at the end do what you want

>
>>
>> >+	u64 tx_credits, regval;
>> >+	struct nix_hw *nix_hw;
>> >+
>> >+	blkaddr = rvu_get_blkaddr(rvu, BLKTYPE_NIX, pcifunc);
>> >+	if (blkaddr < 0)
>> >+		return NIX_AF_ERR_AF_LF_INVALID;
>> >+
>> >+	nix_hw =  get_nix_hw(rvu->hw, blkaddr);
>> >+	if (!nix_hw)
>> >+		return NIX_AF_ERR_INVALID_NIXBLK;
>> >+
>> >+	/* set TL1 sw_xoff */
>> >+	link = nix_get_tx_link(rvu, pcifunc);
>> >+	rvu_write64(rvu, blkaddr, NIX_AF_TL1X_SW_XOFF(link), 1);
>> >+
>> >+	/* wait for link credits to return */
>> >+	tx_credits = nix_hw->tx_credits[link];
>> >+	while (1) {
>>
>> cant we use just for loop if this is simple cnt decrementing?
>Do we see any advantage ?

if something is a clear for loop why make it complicated?
again, not insisting - just asking

>
>>
>> >+		regval = rvu_read64(rvu, blkaddr, NIX_AF_TX_LINKX_NORM_CREDIT(link));
>> >+		if (((regval >> 12) & 0xFFFFF) == tx_credits)
>>
>> FIELD_GET(GENMASK(31, 12), regval) ?
>ACK