Hi,
James Bottomley wrote:
On Wed, 2005-03-23 at 11:14 +0900, Tejun Heo wrote:
When hot-unplugging using scsi_remove_host() function (as usb does), scsi_forget_host() used to be called before scsi_host_cancel(). So, the device gets removed first without request cleanup and scsi_host_cancel() never gets to call scsi_device_cancel() on the removed devices. This results in premature completion of hot-unplugging process with active requests left in queue, eventually leading to hang/offlined device or oops when the active command times out.
This patch makes scsi_remove_host() call scsi_host_cancel() first such that the host is first transited into cancel state and all requests of all devices are killed, and then, the devices are removed. This patch fixes the oops in eh after hot-unplugging bug.
This is actually simply reversing this patch:
http://marc.theaimsgroup.com/?l=linux-scsi&m=109268755500248
And all it does is give us the previous consequences back.
The oops isn't in the eh it's in the usb-storage eh routine.
Well, but it's because scsi midlayer calls back into usb-storage eh after the detaching process is complete.
However, the current host code does need fixing, but the fix is to move it over to a proper state model rather than the current bit twiddling we do.
I agree & am working on it. This patch was mainly to verify Jens' oops.
-- tejun
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