Hello Chandra, I have not seen this patch being submitted to mainstream kernel. When are you planning to submit this patch? Should I open a bugzilla for tracking purposes? Thanks Babu Moger -----Original Message----- From: Chandra Seetharaman [mailto:sekharan@xxxxxxxxxx] Sent: Tuesday, October 07, 2008 2:19 PM To: Moger, Babu Cc: device-mapper development; linux-scsi@xxxxxxxxxxxxxxx Subject: RE: failover does not work with rdac device handler Sorry, I sent an imcomplete patch. Here is the correct one. BTW, The panic you saw is caused by the line (one of the lines you added): dev = container_of(&scsi_dh_data, struct scsi_device, scsi_dh_data); in scsi_dh_release(). We cannot use pointer in a structure to get the parent structure. chandra Keep a reference count of attaches, so that same number of detaches are allowed. ----------- Signed-off-by: Chandra Seetharaman <sekharan@xxxxxxxxxx> --- Index: linux-2.6.27-rc8-git5/drivers/scsi/device_handler/scsi_dh.c =================================================================== --- linux-2.6.27-rc8-git5.orig/drivers/scsi/device_handler/scsi_dh.c +++ linux-2.6.27-rc8-git5/drivers/scsi/device_handler/scsi_dh.c @@ -153,12 +153,28 @@ static int scsi_dh_handler_attach(struct if (sdev->scsi_dh_data) { if (sdev->scsi_dh_data->scsi_dh != scsi_dh) err = -EBUSY; - } else if (scsi_dh->attach) + else + kref_get(&sdev->scsi_dh_data->kref); + } else if (scsi_dh->attach) { err = scsi_dh->attach(sdev); + if (!err) { + kref_init(&sdev->scsi_dh_data->kref); + sdev->scsi_dh_data->sdev = sdev; + } + } return err; } +static void scsi_dh_release(struct kref *kref) +{ + struct scsi_dh_data *scsi_dh_data; + scsi_dh_data = container_of(kref, struct scsi_dh_data, kref); + + if (scsi_dh_data->scsi_dh && scsi_dh_data->scsi_dh->detach) + scsi_dh_data->scsi_dh->detach(scsi_dh_data->sdev); +} + /* * scsi_dh_handler_detach - Detach a device handler from a device * @sdev - SCSI device the device handler should be detached from @@ -176,11 +192,7 @@ static void scsi_dh_handler_detach(struc if (scsi_dh && scsi_dh != sdev->scsi_dh_data->scsi_dh) return; - if (!scsi_dh) - scsi_dh = sdev->scsi_dh_data->scsi_dh; - - if (scsi_dh && scsi_dh->detach) - scsi_dh->detach(sdev); + kref_put(&sdev->scsi_dh_data->kref, scsi_dh_release); } /* Index: linux-2.6.27-rc8-git5/include/scsi/scsi_device.h =================================================================== --- linux-2.6.27-rc8-git5.orig/include/scsi/scsi_device.h +++ linux-2.6.27-rc8-git5/include/scsi/scsi_device.h @@ -6,6 +6,7 @@ #include <linux/spinlock.h> #include <linux/workqueue.h> #include <linux/blkdev.h> +#include <linux/kref.h> #include <scsi/scsi.h> #include <asm/atomic.h> @@ -191,6 +192,8 @@ struct scsi_device_handler { struct scsi_dh_data { struct scsi_device_handler *scsi_dh; + struct kref kref; + struct scsi_device *sdev; /* back reference */ char buf[0]; }; -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
