Re: [PATCH 06/22] [SCSI] mpt2sas, mpt3sas: Removing uppper boundary restriction for the module parameter max_sgl_entries

From: Sreekanth Reddy
Date: Thu Dec 11 2014 - 07:14:12 EST


> @@ -2486,9 +2486,13 @@ _base_allocate_memory_pools(struct MPT2SAS_ADAPTER *ioc, int sleep_flag)
>
> /* command line tunables for max sgl entries */
> if (max_sgl_entries != -1) {
> - ioc->shost->sg_tablesize = (max_sgl_entries <
> - MPT2SAS_SG_DEPTH) ? max_sgl_entries :
> - MPT2SAS_SG_DEPTH;
> + if (max_sgl_entries > MPT2SAS_SG_DEPTH)
> + printk(MPT2SAS_WARN_FMT
> + "setting max_sgl_entries(%d), overriding kernel"
> + " defined SCSI_MAX_SG_SEGMENTS(%d)\n", ioc->name,
> + max_sgl_entries, MPT2SAS_SG_DEPTH);
> + ioc->shost->sg_tablesize = min_t(unsigned short,
> + max_sgl_entries, SCSI_MAX_SG_CHAIN_SEGMENTS);
> } else {
> ioc->shost->sg_tablesize = MPT2SAS_SG_DEPTH;
> }
>
> Wouldn't it be better to print the new scatterlist limit after it has
> been clamped to reflect what it's actually being set to?

but Martin, I though to warn the user that the module parameter
max_sgl_entries value what they provided is greater than the kernel
defined SCSI_MAX_SG_SEGMENTS, whether if this module parameter value
is greater than or less than the SCSI_MAX_SG_CHAIN_SEGMENTS. Also I
thought, user may confuse if see observes SCSI_MAX_SG_CHAIN_SEGMENTS
value instead of max_sgl_entries value in the warning message.

Please let me known If my assumption is wrong. Then I will modify this
patch according to your suggestion i.e I will print the scatterlist
limit after it has been clamped.

Thanks,
Sreekanth
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