Re: [RFC] How to fix an async scan - rmmod race?
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On 04/06/12 15:20, James Bottomley wrote: > On Fri, 2012-04-06 at 11:54 +0200, Tomas Henzl wrote: >> I like this idea(try_module_get) it is easy/elegant and it is used in scsi_rescan_device, >> but a scan can take a lot of time and during that time the driver couldn't be removed. >> When a flag in scsi_remove_host is set then the scan can be cancelled, if the user >> rmmods the driver. > > This is my preferred solution too. The rule for async stuff is either > cancel or wait and since we can't cancel, we need to ensure the wait by > holding the module until the async event has finished. > > Since the whole of the host scan must complete, we need to hold the > module across that, but I bet we also need to hold it across user > triggered target scans as well. As far as I can see the queuecommand call in scsi_dispatch_cmd() can race with module removal - that call can be triggered while the host template is being unloaded. I'm not sure though what the best approach is to fix that race. Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html