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Linux 6.10: work harder to avoid kmem_cache_alloc reuse 

Linux 6.10 change kmem_cache_alloc to be a macro, rather than a
function, such that the old #undef for it in spl-kmem-cache.c would
remove its definition completely, breaking the build.

This inverts the model used before. Rather than always defining the
kmem_cache_* macro, then undefining then inside spl-kmem-cache.c,
instead we make a special tag to indicate we're currently inside
spl-kmem-cache.c, and not defining those in macros in the first place,
so we can use the kernel-supplied kmem_cache_* functions to implement
spl_kmem_cache_*, as we expect.

For all other callers, we create the macros as normal and remove access
to the kernel's own conflicting names.

Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
This commit is contained in:
Rob Norris 2024-05-28 11:56:41 -04:00 committed by Tony Hutter
parent b409892ae5
commit e951dba48a
2 changed files with 13 additions and 18 deletions
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19
include/os/linux/spl/sys/kmem_cache.h
View File

@ -192,22 +192,25 @@ extern void spl_kmem_reap(void);
extern uint64_t spl_kmem_cache_inuse(kmem_cache_t *cache); extern uint64_t spl_kmem_cache_inuse(kmem_cache_t *cache);
extern uint64_t spl_kmem_cache_entry_size(kmem_cache_t *cache); extern uint64_t spl_kmem_cache_entry_size(kmem_cache_t *cache);
#ifndef SPL_KMEM_CACHE_IMPLEMENTING
/*
* Macros for the kmem_cache_* API expected by ZFS and SPL clients. We don't
* define them inside spl-kmem-cache.c, as that uses the kernel's incompatible
* kmem_cache_* facilities to implement ours.
*/
/* Avoid conflicts with kernel names that might be implemented as macros. */
#undef kmem_cache_alloc
#define kmem_cache_create(name, size, align, ctor, dtor, rclm, priv, vmp, fl) \ #define kmem_cache_create(name, size, align, ctor, dtor, rclm, priv, vmp, fl) \
spl_kmem_cache_create(name, size, align, ctor, dtor, rclm, priv, vmp, fl) spl_kmem_cache_create(name, size, align, ctor, dtor, rclm, priv, vmp, fl)
#define kmem_cache_set_move(skc, move) spl_kmem_cache_set_move(skc, move) #define kmem_cache_set_move(skc, move) spl_kmem_cache_set_move(skc, move)
#define kmem_cache_destroy(skc) spl_kmem_cache_destroy(skc) #define kmem_cache_destroy(skc) spl_kmem_cache_destroy(skc)
/*
* This is necessary to be compatible with other kernel modules
* or in-tree filesystem that may define kmem_cache_alloc,
* like bcachefs does it now.
*/
#ifdef kmem_cache_alloc
#undef kmem_cache_alloc
#endif
#define kmem_cache_alloc(skc, flags) spl_kmem_cache_alloc(skc, flags) #define kmem_cache_alloc(skc, flags) spl_kmem_cache_alloc(skc, flags)
#define kmem_cache_free(skc, obj) spl_kmem_cache_free(skc, obj) #define kmem_cache_free(skc, obj) spl_kmem_cache_free(skc, obj)
#define kmem_cache_reap_now(skc) spl_kmem_cache_reap_now(skc) #define kmem_cache_reap_now(skc) spl_kmem_cache_reap_now(skc)
#define kmem_reap() spl_kmem_reap() #define kmem_reap() spl_kmem_reap()
#endif
/* /*
* The following functions are only available for internal use. * The following functions are only available for internal use.

12
module/os/linux/spl/spl-kmem-cache.c
View File

@ -21,6 +21,8 @@
* with the SPL. If not, see <http://www.gnu.org/licenses/>. * with the SPL. If not, see <http://www.gnu.org/licenses/>.
*/ */
#define SPL_KMEM_CACHE_IMPLEMENTING
#include <linux/percpu_compat.h> #include <linux/percpu_compat.h>
#include <sys/kmem.h> #include <sys/kmem.h>
#include <sys/kmem_cache.h> #include <sys/kmem_cache.h>
@ -33,16 +35,6 @@
#include <linux/swap.h> #include <linux/swap.h>
#include <linux/prefetch.h> #include <linux/prefetch.h>
/*
* Within the scope of spl-kmem.c file the kmem_cache_* definitions
* are removed to allow access to the real Linux slab allocator.
*/
#undef kmem_cache_destroy
#undef kmem_cache_create
#undef kmem_cache_alloc
#undef kmem_cache_free
/* /*
* Linux 3.16 replaced smp_mb__{before,after}_{atomic,clear}_{dec,inc,bit}() * Linux 3.16 replaced smp_mb__{before,after}_{atomic,clear}_{dec,inc,bit}()
* with smp_mb__{before,after}_atomic() because they were redundant. This is * with smp_mb__{before,after}_atomic() because they were redundant. This is