Synchronize contrib/linux-kernel with the kernel API

[sirlucjan]

Is your feature request related to a problem? Please describe.

I think it would be a good idea to add the following kernel commits to contrib/linux-kernel:

• torvalds/linux@4fc4187

• torvalds/linux@f3c11cf

• torvalds/linux@5f60d5f (I think the third one is already in one PR)

Describe the solution you'd like

This will allow us to easily update the API on the latest kernel (above 6.12) - the mechanism is described here: https://github.com/facebook/zstd/tree/dev/contrib/linux-kernel#readme

Thanks in advance.

[kdave]

A few days ago the zstd tree was removed from linux-next (https://lore.kernel.org/all/[email protected]/) which makes syncing to kernel a bit harder. I'm offering help to get it back and updated.

[intersectRaven]

I've followed the steps in there to bundle 1.5.7 on my own custom kernel and I believe only the 1st commit's changes needs to be adapted into:
include/linux/zstd.h -> contrib/linux-kernel/linux_zstd.h
lib/zstd/zstd_compress_module.c -> contrib/linux-kernel/zstd_compress_module.c
lib/zstd/zstd_decompress_module.c -> contrib/linux-kernel/zstd_decompress_module.c

The second commit mentioned has already been addressed in 9a3b17c.
The third commit has already been pulled in 92be4be.

After the changes are adapted, the instructions can be used to create a compilable kernel.

[terrelln]

Hey all! I'm beginning work on updating the kernel to zstd-1.5.7 now, and will begin with back-porting the patches mentioned here. Specifically torvalds/linux@4fc4187.

[terrelln]

Thanks for the heads up @kdave! Unless you recommend otherwise, I'll ask for my tree back, and would very much appreciate any support there, if any is needed.

[kdave]

Good news then. To get your tree back you can simply update the tree + branch that is pulled to linux-next and reply to the mail (https://lore.kernel.org/all/[email protected]/). If you want you can I can be 2nd maintainer acting as backup in case the branch needs to be sent to Linus and you for some reason don't have the time. Eg. the 1.5.5 update was ready but never sent, this is something I could do.

[terrelln]

If you're willing to be a 2nd maintainer here, that'd be great! I'm not the most plugged into Linux activity, so your support would be very valuable.