Re: [PATCH 2/4] scsi: qedi: Fix command overqueueing

[Mike Christie <michael.christie@oracle.com>]

On 4/20/26 1:02 PM, Bart Van Assche wrote:
> On 4/20/26 10:47 AM, Mike Christie wrote:
>> On 4/20/26 11:45 AM, Bart Van Assche wrote:
>>> On 4/17/26 3:57 PM, Mike Christie wrote:
>>>> qedi supports a total of can_queue commands over all queues so set
>>>> host_tagset when multiple queues are used.
>>>>
>>>> Signed-off-by: Mike Christie <michael.christie@oracle.com>
>>>> ---
>>>>   drivers/scsi/qedi/qedi_main.c | 2 ++
>>>>   1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/drivers/scsi/qedi/qedi_main.c b/drivers/scsi/qedi/ qedi_main.c
>>>> index 227ff7bd1bdc..0be0a9f30ee2 100644
>>>> --- a/drivers/scsi/qedi/qedi_main.c
>>>> +++ b/drivers/scsi/qedi/qedi_main.c
>>>> @@ -657,6 +657,8 @@ static struct qedi_ctx *qedi_host_alloc(struct pci_dev *pdev)
>>>>       qedi->max_sqes = QEDI_SQ_SIZE;
>>>>       shost->nr_hw_queues = MIN_NUM_CPUS_MSIX(qedi);
>>>> +    if (shost->nr_hw_queues > 1)
>>>> +        shost->host_tagset = 1;
>>>>       pci_set_drvdata(pdev, qedi);
>>>
>>> Why "if (shost->nr_hw_queues > 1)"? It is safe to set host_tagset even
>>> if shost->nr_hw_queues == 1. See e.g. "[PATCH] ufs: core: Use a host-
>>> wide tagset in SDB mode" (https://lore.kernel.org/linux- scsi/20260116180800.3085233-1-bvanassche@acm.org/).
>>>
>> But you can't do batching with host_tagset right?
> 
> Batching? Does this refer to struct io_comp_batch or perhaps to another
> batching feature?
> 
I was talking about when we unplug a queue we try to allocate
the tags/requests in a batch. But, ignore my comment. I mixed up
BLK_MQ_F_TAG_QUEUE_SHARED and BLK_MQ_F_TAG_HCTX_SHARED.

I'll fix my patch.