Re: [PATCH v3 6/8] riscv: Apply acquire/release semantics to arch_xchg/arch_cmpxchg operations

kernel test robot
2025-09-20T14:52:15Z

Hi Xu,

kernel test robot noticed the following build errors:

[auto build test ERROR on robh/for-next]
[also build test ERROR on kvm/queue kvm/next linus/master v6.17-rc6]
[cannot apply to kvm/linux-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Xu-Lu/riscv-add-ISA-extension-parsing-for-Zalasr/20250919-154304
base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
patch link: https://lore.kernel.org/r/20250919073714.83063-7-luxu.kernel%40bytedance.com
patch subject: [PATCH v3 6/8] riscv: Apply acquire/release semantics to arch_xchg/arch_cmpxchg operations
config: riscv-randconfig-002-20250920 (https://download.01.org/0day-ci/archive/20250920/202509202249.rOR3GJbT-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 7c861bcedf61607b6c087380ac711eb7ff918ca6)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250920/202509202249.rOR3GJbT-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509202249.rOR3GJbT-lkp@intel.com/

All errors (new ones prefixed by >>):

In file included from lib/objpool.c:3:
>> include/linux/objpool.h:156:7: error: invalid .org offset '1528' (at offset '1532')
156 | if (try_cmpxchg_release(&slot->head, &head, head + 1))
| ^
include/linux/atomic/atomic-instrumented.h:4899:2: note: expanded from macro 'try_cmpxchg_release'
4899 | raw_try_cmpxchg_release(__ai_ptr, __ai_oldp, __VA_ARGS__); \
| ^
include/linux/atomic/atomic-arch-fallback.h:228:9: note: expanded from macro 'raw_try_cmpxchg_release'
228 | ___r = raw_cmpxchg_release((_ptr), ___o, (_new)); \
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
note: (skipping 4 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
In file included from lib/objpool.c:3:
>> include/linux/objpool.h:156:7: error: invalid .org offset '1528' (at offset '1532')
156 | if (try_cmpxchg_release(&slot->head, &head, head + 1))
| ^
include/linux/atomic/atomic-instrumented.h:4899:2: note: expanded from macro 'try_cmpxchg_release'
4899 | raw_try_cmpxchg_release(__ai_ptr, __ai_oldp, __VA_ARGS__); \
| ^
include/linux/atomic/atomic-arch-fallback.h:228:9: note: expanded from macro 'raw_try_cmpxchg_release'
228 | ___r = raw_cmpxchg_release((_ptr), ___o, (_new)); \
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
note: (skipping 4 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
2 errors generated.
--
>> lib/generic-radix-tree.c:53:12: error: invalid .org offset '1850' (at offset '1854')
53 | if ((v = cmpxchg_release(&radix->root, r, new_root)) == r) {
| ^
include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
4803 | raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
265 | _arch_cmpxchg((ptr), (o), (n), \
| ^
note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
lib/generic-radix-tree.c:74:14: error: invalid .org offset '1862' (at offset '1866')
74 | if (!(n = cmpxchg_release(p, NULL, new_node)))
| ^
include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
4803 | raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
265 | _arch_cmpxchg((ptr), (o), (n), \
| ^
note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
>> lib/generic-radix-tree.c:53:12: error: invalid .org offset '1850' (at offset '1854')
53 | if ((v = cmpxchg_release(&radix->root, r, new_root)) == r) {
| ^
include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
4803 | raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
265 | _arch_cmpxchg((ptr), (o), (n), \
| ^
note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
lib/generic-radix-tree.c:74:14: error: invalid .org offset '1862' (at offset '1866')
74 | if (!(n = cmpxchg_release(p, NULL, new_node)))
| ^
include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
4803 | raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
265 | _arch_cmpxchg((ptr), (o), (n), \
| ^
note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
4 errors generated.
--
In file included from lib/refcount.c:6:
In file included from include/linux/mutex.h:17:
In file included from include/linux/lockdep.h:14:
In file included from include/linux/smp.h:13:
In file included from include/linux/cpumask.h:14:
In file included from include/linux/atomic.h:80:
>> include/linux/atomic/atomic-arch-fallback.h:2083:9: error: invalid .org offset '528' (at offset '532')
2083 | return raw_cmpxchg_release(&v->counter, old, new);
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
265 | _arch_cmpxchg((ptr), (o), (n), \
| ^
arch/riscv/include/asm/cmpxchg.h:238:3: note: expanded from macro '_arch_cmpxchg'
238 | __arch_cmpxchg(".w" lr_sfx, ".w" sc_sfx, ".w" cas_sfx, \
| ^
note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
In file included from lib/refcount.c:6:
In file included from include/linux/mutex.h:17:
In file included from include/linux/lockdep.h:14:
In file included from include/linux/smp.h:13:
In file included from include/linux/cpumask.h:14:
In file included from include/linux/atomic.h:80:
include/linux/atomic/atomic-arch-fallback.h:2083:9: error: invalid .org offset '540' (at offset '544')
2083 | return raw_cmpxchg_release(&v->counter, old, new);
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
265 | _arch_cmpxchg((ptr), (o), (n), \
| ^
arch/riscv/include/asm/cmpxchg.h:238:3: note: expanded from macro '_arch_cmpxchg'
238 | __arch_cmpxchg(".w" lr_sfx, ".w" sc_sfx, ".w" cas_sfx, \
| ^
note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
In file included from lib/refcount.c:6:
In file included from include/linux/mutex.h:17:
In file included from include/linux/lockdep.h:14:
In file included from include/linux/smp.h:13:
In file included from include/linux/cpumask.h:14:
In file included from include/linux/atomic.h:80:
>> include/linux/atomic/atomic-arch-fallback.h:2083:9: error: invalid .org offset '528' (at offset '532')
2083 | return raw_cmpxchg_release(&v->counter, old, new);
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
265 | _arch_cmpxchg((ptr), (o), (n), \
| ^
arch/riscv/include/asm/cmpxchg.h:238:3: note: expanded from macro '_arch_cmpxchg'
238 | __arch_cmpxchg(".w" lr_sfx, ".w" sc_sfx, ".w" cas_sfx, \
| ^
note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
In file included from lib/refcount.c:6:
In file included from include/linux/mutex.h:17:
In file included from include/linux/lockdep.h:14:
In file included from include/linux/smp.h:13:
In file included from include/linux/cpumask.h:14:
In file included from include/linux/atomic.h:80:
include/linux/atomic/atomic-arch-fallback.h:2083:9: error: invalid .org offset '540' (at offset '544')
2083 | return raw_cmpxchg_release(&v->counter, old, new);
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
265 | _arch_cmpxchg((ptr), (o), (n), \
| ^
arch/riscv/include/asm/cmpxchg.h:238:3: note: expanded from macro '_arch_cmpxchg'
238 | __arch_cmpxchg(".w" lr_sfx, ".w" sc_sfx, ".w" cas_sfx, \
| ^
note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
4 errors generated.
--
>> fs/overlayfs/file.c:147:10: error: invalid .org offset '3640' (at offset '3644')
147 | old = cmpxchg_release(&of->upperfile, NULL, upperfile);
| ^
include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
4803 | raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
265 | _arch_cmpxchg((ptr), (o), (n), \
| ^
note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
>> fs/overlayfs/file.c:147:10: error: invalid .org offset '3640' (at offset '3644')
147 | old = cmpxchg_release(&of->upperfile, NULL, upperfile);
| ^
include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
4803 | raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
| ^
include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
77 | #define raw_cmpxchg_release arch_cmpxchg_release
| ^
arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
265 | _arch_cmpxchg((ptr), (o), (n), \
| ^
note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
104 | __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
| ^
arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
94 | ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
| ^
arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
81 | ".org . - (887b - 886b) + (889b - 888b)\n" \
| ^
<inline asm>:27:6: note: instantiated into assembly here
27 | .org . - (887b - 886b) + (889b - 888b)
| ^
2 errors generated.
..

vim +156 include/linux/objpool.h

b4edb8d2d4647a wuqiang.matt 2023-10-17 100
b4edb8d2d4647a wuqiang.matt 2023-10-17 101 /**
b4edb8d2d4647a wuqiang.matt 2023-10-17 102 * objpool_init() - initialize objpool and pre-allocated objects
b4edb8d2d4647a wuqiang.matt 2023-10-17 103 * @pool: the object pool to be initialized, declared by caller
b4edb8d2d4647a wuqiang.matt 2023-10-17 104 * @nr_objs: total objects to be pre-allocated by this object pool
b4edb8d2d4647a wuqiang.matt 2023-10-17 105 * @object_size: size of an object (should be > 0)
b4edb8d2d4647a wuqiang.matt 2023-10-17 106 * @gfp: flags for memory allocation (via kmalloc or vmalloc)
b4edb8d2d4647a wuqiang.matt 2023-10-17 107 * @context: user context for object initialization callback
b4edb8d2d4647a wuqiang.matt 2023-10-17 108 * @objinit: object initialization callback for extra setup
b4edb8d2d4647a wuqiang.matt 2023-10-17 109 * @release: cleanup callback for extra cleanup task
b4edb8d2d4647a wuqiang.matt 2023-10-17 110 *
b4edb8d2d4647a wuqiang.matt 2023-10-17 111 * return value: 0 for success, otherwise error code
b4edb8d2d4647a wuqiang.matt 2023-10-17 112 *
b4edb8d2d4647a wuqiang.matt 2023-10-17 113 * All pre-allocated objects are to be zeroed after memory allocation.
b4edb8d2d4647a wuqiang.matt 2023-10-17 114 * Caller could do extra initialization in objinit callback. objinit()
b4edb8d2d4647a wuqiang.matt 2023-10-17 115 * will be called just after slot allocation and called only once for
b4edb8d2d4647a wuqiang.matt 2023-10-17 116 * each object. After that the objpool won't touch any content of the
b4edb8d2d4647a wuqiang.matt 2023-10-17 117 * objects. It's caller's duty to perform reinitialization after each
b4edb8d2d4647a wuqiang.matt 2023-10-17 118 * pop (object allocation) or do clearance before each push (object
b4edb8d2d4647a wuqiang.matt 2023-10-17 119 * reclamation).
b4edb8d2d4647a wuqiang.matt 2023-10-17 120 */
b4edb8d2d4647a wuqiang.matt 2023-10-17 121 int objpool_init(struct objpool_head *pool, int nr_objs, int object_size,
b4edb8d2d4647a wuqiang.matt 2023-10-17 122 gfp_t gfp, void *context, objpool_init_obj_cb objinit,
b4edb8d2d4647a wuqiang.matt 2023-10-17 123 objpool_fini_cb release);
b4edb8d2d4647a wuqiang.matt 2023-10-17 124
a3b00f10da808b Andrii Nakryiko 2024-04-24 125 /* try to retrieve object from slot */
a3b00f10da808b Andrii Nakryiko 2024-04-24 126 static inline void *__objpool_try_get_slot(struct objpool_head *pool, int cpu)
a3b00f10da808b Andrii Nakryiko 2024-04-24 127 {
a3b00f10da808b Andrii Nakryiko 2024-04-24 128 struct objpool_slot *slot = pool->cpu_slots[cpu];
a3b00f10da808b Andrii Nakryiko 2024-04-24 129 /* load head snapshot, other cpus may change it */
a3b00f10da808b Andrii Nakryiko 2024-04-24 130 uint32_t head = smp_load_acquire(&slot->head);
a3b00f10da808b Andrii Nakryiko 2024-04-24 131
a3b00f10da808b Andrii Nakryiko 2024-04-24 132 while (head != READ_ONCE(slot->last)) {
a3b00f10da808b Andrii Nakryiko 2024-04-24 133 void *obj;
a3b00f10da808b Andrii Nakryiko 2024-04-24 134
a3b00f10da808b Andrii Nakryiko 2024-04-24 135 /*
a3b00f10da808b Andrii Nakryiko 2024-04-24 136 * data visibility of 'last' and 'head' could be out of
a3b00f10da808b Andrii Nakryiko 2024-04-24 137 * order since memory updating of 'last' and 'head' are
a3b00f10da808b Andrii Nakryiko 2024-04-24 138 * performed in push() and pop() independently
a3b00f10da808b Andrii Nakryiko 2024-04-24 139 *
a3b00f10da808b Andrii Nakryiko 2024-04-24 140 * before any retrieving attempts, pop() must guarantee
a3b00f10da808b Andrii Nakryiko 2024-04-24 141 * 'last' is behind 'head', that is to say, there must
a3b00f10da808b Andrii Nakryiko 2024-04-24 142 * be available objects in slot, which could be ensured
a3b00f10da808b Andrii Nakryiko 2024-04-24 143 * by condition 'last != head && last - head <= nr_objs'
a3b00f10da808b Andrii Nakryiko 2024-04-24 144 * that is equivalent to 'last - head - 1 < nr_objs' as
a3b00f10da808b Andrii Nakryiko 2024-04-24 145 * 'last' and 'head' are both unsigned int32
a3b00f10da808b Andrii Nakryiko 2024-04-24 146 */
a3b00f10da808b Andrii Nakryiko 2024-04-24 147 if (READ_ONCE(slot->last) - head - 1 >= pool->nr_objs) {
a3b00f10da808b Andrii Nakryiko 2024-04-24 148 head = READ_ONCE(slot->head);
a3b00f10da808b Andrii Nakryiko 2024-04-24 149 continue;
a3b00f10da808b Andrii Nakryiko 2024-04-24 150 }
a3b00f10da808b Andrii Nakryiko 2024-04-24 151
a3b00f10da808b Andrii Nakryiko 2024-04-24 152 /* obj must be retrieved before moving forward head */
a3b00f10da808b Andrii Nakryiko 2024-04-24 153 obj = READ_ONCE(slot->entries[head & slot->mask]);
a3b00f10da808b Andrii Nakryiko 2024-04-24 154
a3b00f10da808b Andrii Nakryiko 2024-04-24 155 /* move head forward to mark it's consumption */
a3b00f10da808b Andrii Nakryiko 2024-04-24 @156 if (try_cmpxchg_release(&slot->head, &head, head + 1))
a3b00f10da808b Andrii Nakryiko 2024-04-24 157 return obj;
a3b00f10da808b Andrii Nakryiko 2024-04-24 158 }
a3b00f10da808b Andrii Nakryiko 2024-04-24 159
a3b00f10da808b Andrii Nakryiko 2024-04-24 160 return NULL;
a3b00f10da808b Andrii Nakryiko 2024-04-24 161 }
a3b00f10da808b Andrii Nakryiko 2024-04-24 162

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0-DAY CI Kernel Test Service