Re: PATCH 1/5] scsi: megaraid_sas - Add Online Controller Reset to MegaRAID SAS drive

[Tomas Henzl <thenzl@redhat.com>]

On 09/23/2010 04:36 AM, bo yang wrote:
> This patch is too big.  I am using attachment to submit.  Please
> use attached file to apply.  Also let me know if it can't be accepted.
>
> To add the Online controller reset support, driver need to do:
> a). reset the controller chips -- Xscale and Gen2 which will change
> the function calls and add the reset function related to this two
> chips.
> b). during the reset, driver will store the pending cmds which not
> returned by FW to driver's pending queue.  Driver will re-issue those
> pending cmds again to FW after the OCR finished.
> c). In driver's timeout routine, driver will report to OS as reset.
> Also driver's queue routine will block the cmds until the OCR
> finished.
> d). in Driver's ISR routine, if driver get the FW state as state
> change, FW in Failure status and FW support online controller
> reset (OCR), driver will start to do the controller reset.
> e). In driver's IOCTL routine, the application cmds will wait for the
> OCR to finish, then issue the cmds to FW.
>
> Signed-off-by Bo Yang<bo.yang@lsi.com>
>
> ---
>  drivers/scsi/megaraid/megaraid_sas.c |  756 ++++++++++++++++++++++++++++++++---
>  drivers/scsi/megaraid/megaraid_sas.h |   88 +++-
>  2 files changed, 787 insertions(+), 57 deletions(-)
Hi Bo,
in the workqueue function you sleep for 30s,
it's scheduled here - schedule_work(&instance->work_init);

+process_fw_state_change_wq(struct work_struct *work)
+{
...
+		/*waitting for about 20 second before start the second init*/
+		for (wait = 0; wait < 30; wait++) {
+			msleep(1000);
+		}

- this is not a good practice to sleep for a so long time I think
- you should use in your exit function some synchronization 
  for example 'cancel_work_sync', without that if someone rmmods your 
  module, it could then lead to a memory corruption

Tomas