On Tue, May 30, 2023 at 11:40:35AM +0200, Johan Hovold wrote:

On Mon, May 29, 2023 at 09:55:15PM -0400, Linus Torvalds wrote:

quoted

On Mon, May 29, 2023 at 11:18 AM Johan Hovold [off-list ref] wrote:

quoted

I took a closer look at some of the modules that failed to load and
noticed a pattern in that they have dependencies that are needed by more
than one device.

Ok, this is a "maybe something like this" RFC series of two patches -
one trivial one to re-organize things a bit so that we can then do the
real one which uses a filter based on the inode pointer to return an
"idempotent return value" for module loads that share the same inode.

It's entirely untested, and since I'm on the road I'm going to not
really be able to test it. It compiles for me, and the code looks
fairly straightforward, but it's probably buggy.

It's very loosely based on Luis' attempt,  but it
 (a) is internal to module loading
 (b) uses a reliable cookie
 (c) doesn't leave the cookie around randomly for later
 (d) has seen absolutely no testing

Put another way: if somebody wants to play with this, please treat it
as a starting point, not the final thing. You might need to debug
things, and fix silly mistakes.

With the missing spinlock initialisation fixed:

-static struct spinlock idem_lock;
+static DEFINE_SPINLOCK(idem_lock);

this passes basic smoke testing and allows the X13s to boot.

It does not seem to have any significant impact on boot time, but it
avoids some of the unnecessary load attempts as intended:

Took another look at code which modulo some nits like missing spaces
around a + operator and an "ourselfs" typo looks good to me. So with the
spinlock initialisation fixed:

Reviewed-by: Johan Hovold <johan@kernel.org>
Tested-by: Johan Hovold <johan@kernel.org>

Johan