2014-10-04 1:35 GMT+09:00 Christoph Hellwig <hch@xxxxxxxxxxxxx>: > On Sat, Oct 04, 2014 at 01:16:16AM +0900, Akinobu Mita wrote: >> These __scsi_add_device() calls for W-LUs increase the module reference >> count of ufshcd.ko by three. But no one calls scsi_device_put() for >> these W-LUs, so it is impossible to unload ufshcd.ko. >> >> There are scsi_remove_device() calls for W-LUs in ufshcd_scsi_remove_wlus(), >> But these calls do nothing (please see a comment below). >> >> I could fix this issue by putting scsi_device_put() just after each >> __scsi_add_device() call. I'll prepare a patch if I haven't missed >> something. > > >> When ufshcd_scsi_remove_wlus() is called in ufshcd_remove(), these >> three W-LU devices have already been deleted by scsi_remove_host() which >> is called just before ufshcd_scsi_remove_wlus(). The scsi >> device state of these W-LU devices is SDEV_DEL at this time, and >> scsi_remove_device() does nothing. > > > No, we need to keep a reference to avoid them going away due to a manual > delete. We need a scsi_device_put where we currently call > scsi_remove_device I guess. This also works for now. But there is a concern. In the previous email, I said that __scsi_add_device() calls for W-LUs increase the module reference count of ufshcd.ko by three. But the module reference count of ufshcd-pci.ko (or ufshcd-pltfrm.ko) should be increased instead of ufshcd.ko. Because ufshcd.ko is core driver and it just provides library function for the actual LLD (ufshcd-pci.ko and ufshcd-pltfrm.ko). Once this problem is fixed (by setting correct ufshcd_driver_template.module or else way), it is impossible to unload ufshcd-pci.ko (or ufshcd-pltfrm.ko). So the fix I proposed in the previous email plus additional work to avoid breakage with manual delete of W-LUs (specifically, correct mutal exclusion for hba->sdev_ufs_device accesses from ufshcd_slave_destroy() and from ufshcd_set_dev_pwr_mode()) is acceptable? -- 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
