ChangeSet 1.2181.22.3, 2005/03/19 14:46:29-06:00, [EMAIL PROTECTED]
[PATCH] queue <-> sdev reference counting problem
There is a problem with the way sdev is freed currently. The reason is
really that there is a circular referencing problem: the sdev needs to
hold on to the queue, but the queue (through the request function) also
needs to hold on to the sdev.
The easiest way to work-around this problem is to kill the sdev
reference in the queue when the sdev is freed. On invocation of
scsi_request_fn(), kill io to this device.
Signed-off-by: Jens Axboe <[EMAIL PROTECTED]>
Signed-off-by: James Bottomley <[EMAIL PROTECTED]>
scsi_lib.c | 25 ++++++++++++++++++++++++-
scsi_sysfs.c | 4 +++-
2 files changed, 27 insertions(+), 2 deletions(-)
diff -Nru a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
--- a/drivers/scsi/scsi_lib.c 2005-03-30 16:06:59 -08:00
+++ b/drivers/scsi/scsi_lib.c 2005-03-30 16:06:59 -08:00
@@ -1233,6 +1233,22 @@
}
/*
+ * Kill requests for a dead device
+ */
+static void scsi_kill_requests(request_queue_t *q)
+{
+ struct request *req;
+
+ while ((req = elv_next_request(q)) != NULL) {
+ blkdev_dequeue_request(req);
+ req->flags |= REQ_QUIET;
+ while (end_that_request_first(req, 0, req->nr_sectors))
+ ;
+ end_that_request_last(req);
+ }
+}
+
+/*
* Function: scsi_request_fn()
*
* Purpose: Main strategy routine for SCSI.
@@ -1246,10 +1262,16 @@
static void scsi_request_fn(struct request_queue *q)
{
struct scsi_device *sdev = q->queuedata;
- struct Scsi_Host *shost = sdev->host;
+ struct Scsi_Host *shost;
struct scsi_cmnd *cmd;
struct request *req;
+ if (!sdev) {
+ printk("scsi: killing requests for dead queue\n");
+ scsi_kill_requests(q);
+ return;
+ }
+
if(!get_device(&sdev->sdev_gendev))
/* We must be tearing the block queue down already */
return;
@@ -1258,6 +1280,7 @@
* To start with, we keep looping until the queue is empty, or until
* the host is no longer able to accept any more requests.
*/
+ shost = sdev->host;
while (!blk_queue_plugged(q)) {
int rtn;
/*
diff -Nru a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
--- a/drivers/scsi/scsi_sysfs.c 2005-03-30 16:06:59 -08:00
+++ b/drivers/scsi/scsi_sysfs.c 2005-03-30 16:06:59 -08:00
@@ -168,8 +168,10 @@
list_del(&sdev->starved_entry);
spin_unlock_irqrestore(sdev->host->host_lock, flags);
- if (sdev->request_queue)
+ if (sdev->request_queue) {
+ sdev->request_queue->queuedata = NULL;
scsi_free_queue(sdev->request_queue);
+ }
scsi_target_reap(scsi_target(sdev));
-
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