qubes-linux-kernel/patches.fixes/scsi-dh-queuedata-accessors
2010-07-07 13:12:45 +02:00

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From: Hannes Reinecke <hare@suse.de>
Subject: Kernel bug triggered in multipath
References: bnc#486001
Patch-mainline: not yet
Starting multipath on a cciss device will cause a kernel
warning to be triggered. Problem is that we're using the
->queuedata field of the request_queue to derefence the
scsi device; however, for other (non-SCSI) devices this
points to a totally different structure.
So we should rather be using accessors here which make
sure we're only returning valid SCSI device structures.
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
drivers/scsi/device_handler/scsi_dh.c | 10 +++++-----
drivers/scsi/scsi_lib.c | 11 +++++++++++
include/scsi/scsi_device.h | 1 +
3 files changed, 17 insertions(+), 5 deletions(-)
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -438,7 +438,7 @@ int scsi_dh_activate(struct request_queu
struct scsi_device_handler *scsi_dh = NULL;
spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
+ sdev = scsi_device_from_queue(q);
if (sdev && sdev->scsi_dh_data)
scsi_dh = sdev->scsi_dh_data->scsi_dh;
if (!scsi_dh || !get_device(&sdev->sdev_gendev))
@@ -500,7 +500,7 @@ int scsi_dh_handler_exist(const char *na
EXPORT_SYMBOL_GPL(scsi_dh_handler_exist);
/*
- * scsi_dh_handler_attach - Attach device handler
+ * scsi_dh_attach - Attach device handler
* @sdev - sdev the handler should be attached to
* @name - name of the handler to attach
*/
@@ -516,7 +516,7 @@ int scsi_dh_attach(struct request_queue
return -EINVAL;
spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
+ sdev = scsi_device_from_queue(q);
if (!sdev || !get_device(&sdev->sdev_gendev))
err = -ENODEV;
spin_unlock_irqrestore(q->queue_lock, flags);
@@ -530,7 +530,7 @@ int scsi_dh_attach(struct request_queue
EXPORT_SYMBOL_GPL(scsi_dh_attach);
/*
- * scsi_dh_handler_detach - Detach device handler
+ * scsi_dh_detach - Detach device handler
* @sdev - sdev the handler should be detached from
*
* This function will detach the device handler only
@@ -544,7 +544,7 @@ void scsi_dh_detach(struct request_queue
struct scsi_device_handler *scsi_dh = NULL;
spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
+ sdev = scsi_device_from_queue(q);
if (!sdev || !get_device(&sdev->sdev_gendev))
sdev = NULL;
spin_unlock_irqrestore(q->queue_lock, flags);
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1595,6 +1595,17 @@ static void scsi_request_fn(struct reque
spin_lock_irq(q->queue_lock);
}
+struct scsi_device *scsi_device_from_queue(struct request_queue *q)
+{
+ struct scsi_device *sdev = NULL;
+
+ if (q->request_fn == scsi_request_fn)
+ sdev = q->queuedata;
+
+ return sdev;
+}
+EXPORT_SYMBOL_GPL(scsi_device_from_queue);
+
u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
{
struct device *host_dev;
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -297,6 +297,7 @@ extern void starget_for_each_device(stru
extern void __starget_for_each_device(struct scsi_target *, void *,
void (*fn)(struct scsi_device *,
void *));
+extern struct scsi_device *scsi_device_from_queue(struct request_queue *);
/* only exposed to implement shost_for_each_device */
extern struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *,