James:
When a request is deferred in scsi_init_io because the sg table could not
be allocated, the associated scsi_cmnd is not released and the request is
not marked with REQ_DONTPREP. When the command is retried, if
scsi_prep_fn decides to kill it then the scsi_cmnd will never be released.
This patch (as573) changes scsi_init_io so that it calls scsi_put_command
before deferring a request.
Alan Stern
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
It may still be too soon to apply this patch. I don't know how it will
interact with the old scsi_request mechanism (if that is still being
used).
Also, at some stage you will want to delete the code paths in scsi_prep_fn
that assign cmd = req->special, because unprepared requests will _never_
have an already-associated scsi_cmnd.
Index: usb-2.6/drivers/scsi/scsi_lib.c
===================================================================
--- usb-2.6.orig/drivers/scsi/scsi_lib.c
+++ usb-2.6/drivers/scsi/scsi_lib.c
@@ -97,7 +97,6 @@ int scsi_insert_special_req(struct scsi_
}
static void scsi_run_queue(struct request_queue *q);
-static void scsi_release_buffers(struct scsi_cmnd *cmd);
/*
* Function: scsi_unprep_request()
@@ -1040,8 +1039,10 @@ static int scsi_init_io(struct scsi_cmnd
* if sg table allocation fails, requeue request later.
*/
sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
- if (unlikely(!sgpnt))
+ if (unlikely(!sgpnt)) {
+ scsi_unprep_request(req);
return BLKPREP_DEFER;
+ }
cmd->request_buffer = (char *) sgpnt;
cmd->request_bufflen = req->nr_sectors << 9;
@@ -1245,8 +1246,8 @@ static int scsi_prep_fn(struct request_q
*/
ret = scsi_init_io(cmd);
switch(ret) {
+ /* For BLKPREP_KILL/DEFER the cmd was released */
case BLKPREP_KILL:
- /* BLKPREP_KILL return also releases the command */
goto kill;
case BLKPREP_DEFER:
goto defer;
-
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