ide-disk: fix flush requests (take 2)
commit 813a0eb233ee67d7166241a8b389b6a76f2247f9
Author: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
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 reporting the
problem and testing patches (extra thanks to Sebastian for bisecting
it to the guilty commmit).
Tested-by: Sebastian Siewior <ide-bug@ml.breakpoint.cc>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index 3c69822..aed8b31c 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -590,20 +590,24 @@
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));
if (ide_id_has_flush_cache_ext(drive->id) &&
(drive->capacity64 >= (1UL << 28)))
- task.tf.command = WIN_FLUSH_CACHE_EXT;
+ task->tf.command = WIN_FLUSH_CACHE_EXT;
else
- task.tf.command = WIN_FLUSH_CACHE;
- task.tf_flags = IDE_TFLAG_OUT_TF | IDE_TFLAG_OUT_DEVICE;
- task.data_phase = TASKFILE_NO_DATA;
+ task->tf.command = WIN_FLUSH_CACHE;
+ task->tf_flags = IDE_TFLAG_OUT_TF | IDE_TFLAG_OUT_DEVICE |
+ IDE_TFLAG_DYN;
+ task->data_phase = TASKFILE_NO_DATA;
rq->cmd_type = REQ_TYPE_ATA_TASKFILE;
rq->cmd_flags |= REQ_SOFTBARRIER;
- rq->special = &task;
+ rq->special = task;
}
/*