Bartlomiej Zolnierkiewicz wrote:
From: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
Subject: [PATCH] ide-disk: fix flush requests (take 2)
commit 813a0eb233ee67d7166241a8b389b6a76f2247f9
Author: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
Date: Fri Jan 25 22:17:10 2008 +0100
ide: switch idedisk_prepare_flush() to use REQ_TYPE_ATA_TASKFILE requests
...
broke flush requests.
Allocating IDE command structure on the stack for flush requests is not
a very brilliant idea:
- idedisk_prepare_flush() only prepares the request and it doesn't wait
for it to be completed
- there are can be multiple flush requests queued in the queue
Fix the problem (per hints from James Bottomley) by:
- dynamically allocating ide_task_t instance using kmalloc(..., GFP_ATOMIC)
- adding new taskfile flag (IDE_TFLAG_DYN)
- calling kfree() in ide_end_drive_command() if IDE_TFLAG_DYN is set
(while at it rename 'args' to 'task' and fix whitespace damage)
[ This will be fixed properly before 2.6.25 but this bug is rather
critical and the proper solution requires some more work + testing. ]
Thanks to Sebastian Siewior and Christoph Hellwig for reporitng the
problem and testing patches (extra thanks to Sebastian for bisecting
it to the guilty commmit).
Cc: Sebastian Siewior <ide-bug@xxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
Cc: Tejun Heo <htejun@xxxxxxxxx>
Cc: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
Acked-by: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx>
Index: b/drivers/ide/ide-disk.c
===================================================================
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -590,20 +590,24 @@ static ide_proc_entry_t idedisk_proc[] =
static void idedisk_prepare_flush(struct request_queue *q, struct request *rq)
{
ide_drive_t *drive = q->queuedata;
- ide_task_t task;
+ ide_task_t *task = kmalloc(sizeof(*task), GFP_ATOMIC);
- memset(&task, 0, sizeof(task));
+ /* FIXME: map struct ide_taskfile on rq->cmd[] */
+ BUG_ON(task == NULL);
+
+ memset(task, 0, sizeof(*task));
Why not kzalloc() then?
MBR, Sergei
-
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