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| author | Chandra Seetharaman <sekharan@us.ibm.com> | 2009-06-27 04:30:06 +0200 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@suse.de> | 2009-08-23 00:51:51 +0200 |
| commit | 6c10db72c94818573552fd71c89540da325efdfb (patch) | |
| tree | 6afa9b0431d22638a1a11dfe3c5924b8e1a8e2f3 /drivers/scsi/device_handler | |
| parent | [SCSI] update scsi/constants.c (diff) | |
| download | linux-6c10db72c94818573552fd71c89540da325efdfb.tar.xz linux-6c10db72c94818573552fd71c89540da325efdfb.zip | |
[SCSI] scsi_dh: Reference count scsi_dh_attach
Problem reported: http://marc.info/?l=dm-devel&m=124585978305866&w=2
scsi_dh does not do a refernce count for attach/detach, and this affects
the way it is supposed to work with multipath when a device is not
in the dev_list of the hardware handler.
This patch adds a reference count that counts each attach.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers/scsi/device_handler')
| -rw-r--r-- | drivers/scsi/device_handler/scsi_dh.c | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c index a518f2eff19a..53a7385e1b4d 100644 --- a/drivers/scsi/device_handler/scsi_dh.c +++ b/drivers/scsi/device_handler/scsi_dh.c @@ -153,12 +153,24 @@ static int scsi_dh_handler_attach(struct scsi_device *sdev, 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 __detach_handler (struct kref *kref) +{ + struct scsi_dh_data *scsi_dh_data = container_of(kref, struct scsi_dh_data, kref); + 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 @@ -180,7 +192,7 @@ static void scsi_dh_handler_detach(struct scsi_device *sdev, 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, __detach_handler); } /* @@ -474,7 +486,6 @@ int scsi_dh_attach(struct request_queue *q, const char *name) if (!err) { err = scsi_dh_handler_attach(sdev, scsi_dh); - put_device(&sdev->sdev_gendev); } return err; @@ -505,10 +516,8 @@ void scsi_dh_detach(struct request_queue *q) return; if (sdev->scsi_dh_data) { - /* if sdev is not on internal list, detach */ scsi_dh = sdev->scsi_dh_data->scsi_dh; - if (!device_handler_match(scsi_dh, sdev)) - scsi_dh_handler_detach(sdev, scsi_dh); + scsi_dh_handler_detach(sdev, scsi_dh); } put_device(&sdev->sdev_gendev); } |