On Sun, Jun 25, 2006 at 04:15:26PM -0500, James Bottomley wrote:
> Actually, the first problem is that SCSI doesn't compile as a module at
> all: late_initcalls are defined to be module_init calls for modules.
> Your adding this to scsi_scan.c now gives us two module_init calls,
> which won't build. I fixed this by putting an #ifdef MODULE around the
> late_initcall.
I think that's a good idea (well, I would, I suggested it to you ;-)
> > There's a potential solution to this. If we add a hook to sys_module_init
> > such that it'll call a specified function before returning, we can make
> > it wait until all scans are done. This way, userspace never sees the
> > asynchronous scanning behaviour. But if you have devices of different
> > types, you won't get the overlapping scans.
>
> How about this solution which works for me with debian on a huge 6 bus
> scsi machine: it introduces a new module scsi_wait_scan.ko whose sole
> job is to wait for the scans to complete in its init function. The
> initrd/initramfs sequence now becomes:
>
> insert all other modules
> modprobe scsi_wait_scan
I think that's a great idea. I wonder about making it always fail
initialisation, since then it can be loaded multiple times without being
unloaded. I think Arjan was suggesting some proc or sysfs file that
would cause scsi_complete_async_scans() to be called, but I couldn't
figure out where a good place to put such a file would be.
> @@ -22,6 +22,10 @@
>
> obj-$(CONFIG_SCSI) += scsi_mod.o
>
> +ifeq ("$(CONFIG_SCSI)", "m")
> + obj-m += scsi_wait_scan.o
> +endif
We seem to have a bit of an allergy to conditionals in Makefiles these
days; how about:
tmp-$(CONFIG_SCSI) := scsi_wait_scan.o
obj-m += $(tmp-m)
>
> -static int scsi_complete_async_scans(void)
> +int scsi_complete_async_scans(void)
> {
> struct async_scan_data *data;
>
> @@ -157,8 +157,10 @@
> kfree(data);
> return 0;
> }
Do you think it's worth putting in something like:
/* Only exported for the benefit of scsi_wait_scan */
And maybe ...
#ifdef MODULE
/* Only exported for the benefit of scsi_wait_scan */
EXPORT_SYMBOL_GPL(scsi_complete_async_scans);
#else
late_initcall(scsi_complete_async_scans);
#endif
I really don't want to see driver authors calling it -- if they are,
something's gone pretty horribly wrong.
-
: 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
