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| author | Christian Brauner <brauner@kernel.org> | 2025-11-03 00:14:37 +0100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2025-11-04 12:36:24 +0100 |
| commit | e0876bde29c42c5de8ad087b5df7cd27b29defec (patch) | |
| tree | 0dbcb9b9afdbec28ea7741f11feaafa5e551c165 /include/linux/cleanup.h | |
| parent | dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa (diff) | |
| parent | 1ad5b411afc327ae50e569dbfa15774e0baefa68 (diff) | |
Merge patch series "creds: add {scoped_}with_kernel_creds()"
Christian Brauner <brauner@kernel.org> says:
A few months ago I did work to make override_creds()/revert_creds()
completely reference count free - mostly for the sake of
overlayfs but it has been beneficial to everyone using this.
In a recent pull request from Jens that introduced another round of
override_creds()/revert_creds() for nbd Linus asked whether we could
avoide the prepare_kernel_creds() calls that duplicate the kernel
credentials and then drop them again later.
Yes, we can actually. We can use the guard infrastructure to completely
avoid the allocation and then also to never expose the temporary
variable to hold the kernel credentials anywhere in the callers.
So add with_kernel_creds() and scoped_with_kernel_creds() for this
purpose. Also take the opportunity to fixup the scoped_class() macro I
introduced two cycles ago.
* patches from https://patch.msgid.link/20251103-work-creds-init_cred-v1-0-cb3ec8711a6a@kernel.org:
unix: don't copy creds
target: don't copy kernel creds
nbd: don't copy kernel creds
firmware: don't copy kernel creds
cred: add {scoped_}with_kernel_creds
cred: make init_cred static
cred: add kernel_cred() helper
cleanup: fix scoped_class()
Link: https://patch.msgid.link/20251103-work-creds-init_cred-v1-0-cb3ec8711a6a@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'include/linux/cleanup.h')
| -rw-r--r-- | include/linux/cleanup.h | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h index 2573585b7f06..19c7e475d3a4 100644 --- a/include/linux/cleanup.h +++ b/include/linux/cleanup.h @@ -290,15 +290,16 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ class_##_name##_t var __cleanup(class_##_name##_destructor) = \ class_##_name##_constructor -#define scoped_class(_name, var, args) \ - for (CLASS(_name, var)(args); \ - __guard_ptr(_name)(&var) || !__is_cond_ptr(_name); \ - ({ goto _label; })) \ - if (0) { \ -_label: \ - break; \ +#define __scoped_class(_name, var, _label, args...) \ + for (CLASS(_name, var)(args); ; ({ goto _label; })) \ + if (0) { \ +_label: \ + break; \ } else +#define scoped_class(_name, var, args...) \ + __scoped_class(_name, var, __UNIQUE_ID(label), args) + /* * DEFINE_GUARD(name, type, lock, unlock): * trivial wrapper around DEFINE_CLASS() above specifically |