ChangeSet 1.2181.22.22, 2005/03/30 13:52:14-06:00, [EMAIL PROTECTED](none)
Fix SCSI internal requests hang
When a device is being torn down (mostly in USB ejection)
we hit conditions where SCSI hangs in wait_for_completion().
The reason is that the scsi request prep function does a
state check on the device and rejects it with BLKPREP_KILL if
we're in the DEL (going away, no more I/O) state.
Unfortunately, I/O submitted by scsi_wait_req() doesn't have
its request->end_io initialised, so we're never notified of
this (the submit path expects everything to come back via
the scsi_request->sr_done() routine, which only happens
if the I/O actually gets submitted.
Note: almost everything that uses scsi_do_request() is wrong
not only in this regard but also on other things, like ending
tags.
Problem Diagnosed with help from: Tejun Heo <[EMAIL PROTECTED]>
Signed-off-by: James Bottomley <[EMAIL PROTECTED]>
scsi_lib.c | 11 +++++++++++
1 files changed, 11 insertions(+)
diff -Nru a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
--- a/drivers/scsi/scsi_lib.c 2005-03-30 16:23:58 -08:00
+++ b/drivers/scsi/scsi_lib.c 2005-03-30 16:23:58 -08:00
@@ -252,6 +252,16 @@
complete(req->waiting);
}
+/* This is the end routine we get to if a command was never attached
+ * to the request. Simply complete the request without changing
+ * rq_status; this will cause a DRIVER_ERROR. */
+static void scsi_wait_req_end_io(struct request *req)
+{
+ BUG_ON(!req->waiting);
+
+ complete(req->waiting);
+}
+
void scsi_wait_req(struct scsi_request *sreq, const void *cmnd, void *buffer,
unsigned bufflen, int timeout, int retries)
{
@@ -259,6 +269,7 @@
sreq->sr_request->waiting = &wait;
sreq->sr_request->rq_status = RQ_SCSI_BUSY;
+ sreq->sr_request->end_io = scsi_wait_req_end_io;
scsi_do_req(sreq, cmnd, buffer, bufflen, scsi_wait_done,
timeout, retries);
wait_for_completion(&wait);
-
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