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author | Jean-Sébastien Pédron <dumbbell@FreeBSD.org> | 2023-02-20 20:50:29 +0000 |
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committer | Jean-Sébastien Pédron <dumbbell@FreeBSD.org> | 2023-03-20 20:47:36 +0000 |
commit | 1b4e08b4832deeea4b9121cdaed4f6700bdab03f (patch) | |
tree | 23f3d80c1d5fc8907ba4eab6aac83252bbedaaf0 /sys | |
parent | eef905a85907102bc00b76b5b135c24cabe0456a (diff) | |
download | src-1b4e08b4832deeea4b9121cdaed4f6700bdab03f.tar.gz src-1b4e08b4832deeea4b9121cdaed4f6700bdab03f.zip |
linuxkpi: Support non-NULL zero-size pointers
DRM drivers set some pointers to `ZERO_SIZE_PTR` directly (without
allocating anything), to treat pointers which were "initialized" (set to
`ZERO_SIZE_PTR`) with no memory allocation like really allocated
pointers. NULL isn't used because it represents a third state.
Reviewed by: emaste, manu
Approved by: emaste, manu
Differential Revision: https://reviews.freebsd.org/D39055
Diffstat (limited to 'sys')
-rw-r--r-- | sys/compat/linuxkpi/common/include/linux/slab.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/sys/compat/linuxkpi/common/include/linux/slab.h b/sys/compat/linuxkpi/common/include/linux/slab.h index 915f33acf67e..a2cce4cfe75a 100644 --- a/sys/compat/linuxkpi/common/include/linux/slab.h +++ b/sys/compat/linuxkpi/common/include/linux/slab.h @@ -90,7 +90,8 @@ struct linux_kmem_cache; /* drm-kmod 5.4 compat */ #define kfree_async(ptr) kfree(ptr); -#define ZERO_OR_NULL_PTR(x) ((x) == NULL) +#define ZERO_SIZE_PTR ((void *)16) +#define ZERO_OR_NULL_PTR(x) ((x) == NULL || (x) == ZERO_SIZE_PTR) static inline gfp_t linux_check_m_flags(gfp_t flags) @@ -195,6 +196,9 @@ extern void linux_kfree_async(void *); static inline void kfree(const void *ptr) { + if (ZERO_OR_NULL_PTR(ptr)) + return; + if (curthread->td_critnest != 0) linux_kfree_async(__DECONST(void *, ptr)); else @@ -204,6 +208,9 @@ kfree(const void *ptr) static __inline void kfree_sensitive(const void *ptr) { + if (ZERO_OR_NULL_PTR(ptr)) + return; + zfree(__DECONST(void *, ptr), M_KMALLOC); } |