Messages in this thread | | | Subject | Re: [PATCH] scsi: isci: initialize shost fully before calling scsi_add_host() | From | John Garry <> | Date | Mon, 14 Jan 2019 12:10:23 +0000 |
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On 12/01/2019 02:34, Martin K. Petersen wrote: > > John, > >> So how about just drop these APIs and let the user set the shost >> protection parameters directly, like other shost parameters, > > The protection interfaces here obviously predate the block layer > allocation changes that made this particular issue pop up. > >> which should make it a bit clearer when these should be set, >> i.e. before scsi_add_host()? > > In general, I am not so keen on the somewhat messy intersection between > the host parameters and the host template. The static host templates > made lots of sense in the days of Seagate ST01 and fixed hardware > capabilities. But reality is that most modern controllers have to query > firmware interfaces to figure out what their actual capabilities are.
Hi Martin,
I am not suggested setting the parameters via scsi host template, but rather dynamically (as we currently do) but just drop the set helper functions, like:
shost->max_channel = 1; shost->max_cmd_len = 16;
...
if (hisi_hba->prot_mask) { dev_info(dev, "Registering for DIF/DIX prot_mask=0x%x\n", prot_mask); - scsi_host_set_prot(hisi_hba->shost, prot_mask); + shost->prot_capabilities = prot_mask; }
rc = scsi_add_host(shost, dev); if (rc) goto err_out_ha;
rc = sas_register_ha(sha); if (rc) goto err_out_register_ha;
I find that it is not crystal clear when scsi_host_set_prot() and scsi_host_set_guard() should be called, but not so for setting the shost parameters directly, which is common.
> > So in this case I think that accessor functions are actually better > because they allow us to print a big fat warning when you twiddle > something you shouldn't post-initialization. So that's something I think > we could--and should--improve. >
Sure, this is an alternative, but I would rather make it obvious when these parameters should be set so that this would not be required.
Thanks, John
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