[dm-devel] [PATCH 3/4] scsi_dh_rdac: Adding the match function for rdac device handler
Hannes Reinecke
hare at suse.de
Wed Nov 2 07:20:31 UTC 2011
On 11/01/2011 06:19 PM, Moger, Babu wrote:
> This patch introduces the match function for rdac device handler. Without this,
> sometimes handler attach fails during the device_add. The match function was
> introduced by this patch
> http://www.spinics.net/lists/linux-scsi/msg54284.html
>
> Signed-off-by: Babu Moger<babu.moger at netapp.com>
> ---
>
> --- linux/drivers/scsi/device_handler/scsi_dh_rdac.c.orig 2011-10-31 11:25:44.000000000 -0500
> +++ linux/drivers/scsi/device_handler/scsi_dh_rdac.c 2011-10-31 11:31:34.000000000 -0500
> @@ -819,6 +819,21 @@ static const struct scsi_dh_devlist rdac
> {NULL, NULL},
> };
>
> +static bool rdac_match(struct scsi_device *sdev)
> +{
> + int i;
> +
> + for (i = 0; rdac_dev_list[i].vendor; i++) {
> + if (!strncmp(sdev->vendor, rdac_dev_list[i].vendor,
> + strlen(rdac_dev_list[i].vendor))&&
> + !strncmp(sdev->model, rdac_dev_list[i].model,
> + strlen(rdac_dev_list[i].model))) {
> + return true;
> + }
> + }
> + return false;
> +}
> +
> static int rdac_bus_attach(struct scsi_device *sdev);
> static void rdac_bus_detach(struct scsi_device *sdev);
>
> @@ -831,6 +846,7 @@ static struct scsi_device_handler rdac_d
> .attach = rdac_bus_attach,
> .detach = rdac_bus_detach,
> .activate = rdac_activate,
> + .match = rdac_match,
> };
>
> static int rdac_bus_attach(struct scsi_device *sdev)
>
As stated in the other mail, I guess we would need to have a check
if the LUN is in ALUA mode.
And, btw, the _original_ intention was to allow vendor-specific
device_handler to do some better probing, eg querying some
vendor-specific VPD pages.
Especially for RDAC it would make far more sense to query the
existence and format of one of the RDAC-specific VPD pages (eg 0xC2,
0xC4, or 0xC8) and use that for matching.
Then you could do away with the vendor/model array altogether here
and we wouldn't need to update the rdac handler every time a new
array comes out or has been rebranded by some OEM.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare at suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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