On Wed, Nov 02 2011 at 11:23am -0400, Moger, Babu <Babu.Moger@xxxxxxxxxx> wrote: > > -----Original Message----- > > From: Hannes Reinecke [mailto:hare@xxxxxxx] > > Sent: Wednesday, November 02, 2011 2:21 AM > > To: dm-devel@xxxxxxxxxx > > Subject: Re: [dm-devel] [PATCH 3/4] scsi_dh_rdac: Adding the match > > function for rdac device handler > > > > 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@xxxxxxxxxx> > > > --- > > > > > > --- 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. > > OK. I will add the check for TPGS. I will send the patches tomorrow. > For sending the VPD pages(0xC2, 0xC4 and 0xC8), I think we need be little careful here. > This includes sending these commands to every possible device in the system. That is what we want to avoid. > I will investigate more on that. That will be my next set of patches independent of this. Much appreciated. I agree with Hannes, ideally we wouldn't need the rdac dev_list. What about the issue where the appropriate scsi_dh isn't attached during scan (resulting in boot failures, trespasses, etc)? Hannes, I know you had plans for how to address the early scsi_dh attachment (and this match() work is a great step forward). I just wanted to touch base with you on what your current vision is on how to achieve proper early scsi_dh attachment (and what the remaining TODO is). Thanks, Mike -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
