Re: [PATCH] scsi_lib.c: sleeping function called from invalidcontext

[James Bottomley]

On Tue, 2009-10-06 at 12:30 +0000, iceberg wrote:
> James, what about code where spin_unlock is called before scsi_device_put, 
> especially for avoiding atomic context?
> In code like 
> 	spin_unlock
> 	scsi_device_put
> 	spin_lock
> Is spin_unlock/spin_lock redundant?

Depends on context ... most of them are actually swapping locks or
providing pre-emption points ... it could be redundant, but doesn't have
to be.

> Why do we need scsi_device_get/scsi_device_put pair in scsi_lib.c at all? If 
> we are sure that scsi_device_put is always not last, for what purpose do we 
> call it together with scsi_device_get in the loop?

We're not sure (and never can be in a hotplug world) that any put isn't
the last one.

James


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/