Hi Pat,
General comments / questions below:
On Mon, Sep 27, 2010 at 4:14 PM, Thomson, Patrick S
<patrick.s.thomson@xxxxxxxxx> wrote:
> Hello,
>
> I'm working on a SAS driver for Intel's Patsburg chipset and ran across a problem (for me) when libsas creates a port. Specifically, it appears that libsas will use only use the attached sas address when creating a port, instead of the sas address on each side of the link. What I'd like to propose is to modify port creation such that, based on a flag stored in struct sas_ha_struct, that the SAS address on the initiator side can be taken into account. If the flag is not set, then the original behavior is in force.
>
> The main point is that the original behavior is the default, and if anyone wants to use the modified port creation, they call sas_ha_struct.notify_libsas_config() right after sas_ha_register during module init.
>
Shouldn't this just be the default without a configuration option?
For cases where port->sas_addr != phy->sas_addr I assume you would
always want this new behavior regardless of the flag??
> Thanks!
> Pat Thomson
>
> diff -Nau old/include/scsi/libsas.h new/include/scsi/libsas.h
> --- old/include/scsi/libsas.h 2010-09-27 14:23:14.142380393 -0700
> +++ new/include/scsi/libsas.h 2010-09-27 15:26:38.040818779 -0700
> @@ -89,6 +89,11 @@
> DISC_NUM_EVENTS = 3,
> };
>
> +enum cfg_state {
> + CFGE_USE_HOST_TARGET_SAS = 0U, /* struct sas_ha_struct.use_host_phy_addr */
> + CFGE_USE_ONLY_TARGET_SAS = 1, /* struct sas_ha_struct.use_host_phy_addr */
> +};
> +
> /* ---------- Expander Devices ---------- */
>
> #define to_dom_device(_obj) container_of(_obj, struct domain_device, dev_obj)
> @@ -344,6 +349,9 @@
>
> struct scsi_core core;
>
> + spinlock_t libsas_config_lock;
> + unsigned int use_host_phy_addr; /* defaults to 0 */
> +
Reading an int is assumed atomic so we wouldn't need a lock to set or
clear this flag. Something like this would be better done at init
time. Maybe if you needed it for ordering you could do something like
use_host_phy_addr=1
spin_lock();
spin_unlock();
...but that does not appear to be the case here.
--
Dan
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