[2.1] linux/spl/kmem_cache: undefine kmem_cache_alloc before defining it
#15143
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
RaitoBezarius
changed the title
kmem_cache_alloc before defining itkmem_cache_alloc before defining it
This was referenced Aug 2, 2023
When compiling a kernel with bcachefs and zfs, the two macros will collide, making it impossible to have both filesystems. It is sufficient to just undefine the macro before calling it. On why this should be in ZFS rather than bcachefs, currently, bcachefs is not a in-tree filesystem, but, it has a reasonably high chance of getting included soon. This avoids the breakage in ZFS early, this patch may be distributed downstream in NixOS and is already used there.
RaitoBezarius
force-pushed
the
bcachefs-compat
branch
from
97bc047
to
ec641e5
Compare
behlendorf
reviewed
Aug 2, 2023
| * or in-tree filesystem that may define kmem_cache_alloc, | ||
| * like bcachefs does it now. | ||
| */ | ||
| #undef kmem_cache_alloc |
There was a problem hiding this comment.
I'd recommend wrapping this #undef with a #ifdef kmem_cache_alloc guard. This will avoid any pedantic compiler warnings about undef'ing a define which doesn't exist.
There was a problem hiding this comment.
Done in #15144 which is the rebased version.
There was a problem hiding this comment.
We can close this one if you want.
There was a problem hiding this comment.
Great. Let's go ahead and open new PRs for the backports after it's merged.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Motivation and Context
When compiling a kernel with bcachefs and zfs, the two macros will collide, making it impossible to have both filesystems.
It is sufficient to just undefine the macro before calling it.
On why this should be in ZFS rather than bcachefs, currently, bcachefs is not an in-tree filesystem, but, it has a reasonably high chance of getting included soon.
This avoids the breakage in ZFS early, this patch may be distributed downstream in NixOS and is already used there.
I will send the PR for 2.2 too (on master).
Description
Undefining the macro
kmem_cache_allocbefore its redefinition to ensure we have "the right one".How Has This Been Tested?
I have been running a NixOS system with a bcachefs rootfs and various ZFS external disks with it for more than 2 weeks now.
I did not run specific tests beyond workstation-class usage.
See NixOS/nixpkgs#243075 the downstream PR.
Types of changes
Checklist:
Signed-off-by.