Matthew Wilcox wrote: > On Sat, Sep 08, 2007 at 05:14:21PM +0900, Tejun Heo wrote: >> Matthew Wilcox wrote: >>> By using the scsi async probing code, we can remove the 'sync' argument >>> from ata_scsi_scan_host(): >> Hmmm... How so? @sync is there to keep device numbering stable even >> when SCSI scan fails due to allocation failure. I don't see how async >> probing changes that. > > async probing also keeps device numbering stable. As long as the device > responds within ten seconds (and the current code has half a second as > the timeout), it'll get the same number it would have had, even though > other hosts have successfully completed their probes during that time. The @sync parameter is to work around GFP_ATOMIC allocation in SCSI scan code. A libata SCSI host can have upto 15 devices with PMP and with multiple devices allocation failure is not so rare, probably because libata SCSI scanning is done back-to-back in rapid succession. The proper fix is probably to make SCSI scanning code not use GFP_ATOMIC (there doesn't seem to be any reason to) but @sync is the bandaid till that happens. Thanks. -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
