Re: [PATCH v1 01/20] [SCSI] mpt3sas: Added Combined Reply Queue feature to extend up-to 96 MSIX vector support

From: Martin K. Petersen
Date: Fri Jun 19 2015 - 10:58:47 EST


>>>>> "Sreekanth" == Sreekanth Reddy <sreekanth.reddy@xxxxxxxxxxxxx> writes:

Sreekanth,

It's fine that you outline the 96 / 12 = 8 layout in the patch
description. But that relationship is not made clear when reading the
code. Please add a comment describing why things are set up this way.

> @@ -1009,8 +1009,15 @@ _base_interrupt(int irq, void *bus_id)
> }
>
> wmb();
> - writel(reply_q->reply_post_host_index | (msix_index <<
> - MPI2_RPHI_MSIX_INDEX_SHIFT), &ioc->chip->ReplyPostHostIndex);
> + if (ioc->msix96_vector) {
> + writel(reply_q->reply_post_host_index | ((msix_index & 7) <<
> + MPI2_RPHI_MSIX_INDEX_SHIFT),
> + ioc->replyPostRegisterIndex[msix_index/8]);
> + } else {
> + writel(reply_q->reply_post_host_index | (msix_index <<
> + MPI2_RPHI_MSIX_INDEX_SHIFT),
> + &ioc->chip->ReplyPostHostIndex);
> + }

Too many brackets. Why don't you do:

index = reply_q->reply_post_host_index |
((msix_index & 7) << MPI_RPHI_MSIX_INDEX_SHIFT);

if (ioc->msix96_vector)
writel(index, ioc->replyPostRegisterIndex[msix_index / 8]);
else
writel(index, &ioc->chip->ReplyPostHostIndex);

> + if (ioc->msix96_vector && ioc->reply_queue_count > 8) {
> + /* If this is an 96 vector supported device,
> + set up ReplyPostIndex addresses */

Bad comment formatting.

> + ioc->replyPostRegisterIndex = kcalloc(12,
> + sizeof(resource_size_t *), GFP_KERNEL);
[...]
> + for (i = 0; i < 12; i++) {

Make 12 a constant or at the very least a variable with a comment.

> + ioc->replyPostRegisterIndex[i] = (resource_size_t *)
> + ((u8 *)&ioc->chip->Doorbell +
> + MPI25_SUP_REPLY_POST_HOST_INDEX_OFFSET +
> + (i * 0x10));

0x10 - Another magic constant.

> @@ -4522,8 +4554,16 @@ _base_make_ioc_operational(struct MPT3SAS_ADAPTER *ioc, int sleep_flag)
>
> /* initialize reply post host index */
> list_for_each_entry(reply_q, &ioc->reply_queue_list, list) {
> - writel(reply_q->msix_index << MPI2_RPHI_MSIX_INDEX_SHIFT,
> - &ioc->chip->ReplyPostHostIndex);
> + if (ioc->msix96_vector) {
> + writel((reply_q->msix_index & 7)<<
> + MPI2_RPHI_MSIX_INDEX_SHIFT,
> + ioc->replyPostRegisterIndex[reply_q->msix_index/8]);
> + } else {
> + writel(reply_q->msix_index <<
> + MPI2_RPHI_MSIX_INDEX_SHIFT,
> + &ioc->chip->ReplyPostHostIndex);
> + }
> +

Too many brackets.

--
Martin K. Petersen Oracle Linux Engineering
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