Similar to kmemdup(), but support large amount of bytes with kvmalloc()
and does *not* guarantee that the result will be physically contiguous.
Use only in cases where kvmalloc() is needed and free it with kvfree().
Suggested-by: Daniel Borkmann <[email protected]>
Signed-off-by: Hao Sun <[email protected]>
---
This pattern has been used in several places and we're also going to
do this[1], seems reasonable to add this so that bpf and in future
others could make use of it.
[1] https://lore.kernel.org/bpf/[email protected]/T/#t
---
include/linux/string.h | 1 +
mm/util.c | 24 +++++++++++++++++++++++-
2 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/include/linux/string.h b/include/linux/string.h
index db28802ab0a6..c062c581a98b 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -177,6 +177,7 @@ extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
extern const char *kstrdup_const(const char *s, gfp_t gfp);
extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
extern void *kmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
+extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
diff --git a/mm/util.c b/mm/util.c
index b56c92fb910f..cec9327b27b4 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -120,7 +120,8 @@ EXPORT_SYMBOL(kstrndup);
* @len: memory region length
* @gfp: GFP mask to use
*
- * Return: newly allocated copy of @src or %NULL in case of error
+ * Return: newly allocated copy of @src or %NULL in case of error,
+ * result is physically contiguous. Use kfree() to free.
*/
void *kmemdup(const void *src, size_t len, gfp_t gfp)
{
@@ -133,6 +134,27 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp)
}
EXPORT_SYMBOL(kmemdup);
+/**
+ * kvmemdup - duplicate region of memory
+ *
+ * @src: memory region to duplicate
+ * @len: memory region length
+ * @gfp: GFP mask to use
+ *
+ * Return: newly allocated copy of @src or %NULL in case of error,
+ * result may be not physically contiguous. Use kvfree() to free.
+ */
+void *kvmemdup(const void *src, size_t len, gfp_t gfp)
+{
+ void *p;
+
+ p = kvmalloc(len, gfp);
+ if (p)
+ memcpy(p, src, len);
+ return p;
+}
+EXPORT_SYMBOL(kvmemdup);
+
/**
* kmemdup_nul - Create a NUL-terminated string from unterminated data
* @s: The data to stringify
base-commit: f9ff5644bcc04221bae56f922122f2b7f5d24d62
--
2.39.0
Hi Hao,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on f9ff5644bcc04221bae56f922122f2b7f5d24d62]
url: https://github.com/intel-lab-lkp/linux/commits/Hao-Sun/mm-new-primitive-kvmemdup/20221219-122348
base: f9ff5644bcc04221bae56f922122f2b7f5d24d62
patch link: https://lore.kernel.org/r/20221219042126.3396-1-sunhao.th%40gmail.com
patch subject: [PATCH] mm: new primitive kvmemdup()
config: sh-allmodconfig
compiler: sh4-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/29c8ee8f5f8fcd8f52aa6912bdb55f3dc135b5a0
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Hao-Sun/mm-new-primitive-kvmemdup/20221219-122348
git checkout 29c8ee8f5f8fcd8f52aa6912bdb55f3dc135b5a0
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sh olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sh SHELL=/bin/bash security/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
>> security/apparmor/policy_unpack.c:164:14: error: conflicting types for 'kvmemdup'; have 'void *(const void *, size_t)' {aka 'void *(const void *, unsigned int)'}
164 | static void *kvmemdup(const void *src, size_t len)
| ^~~~~~~~
In file included from include/linux/bitmap.h:11,
from include/linux/cpumask.h:12,
from include/linux/smp.h:13,
from include/linux/lockdep.h:14,
from include/linux/rcupdate.h:29,
from include/linux/rculist.h:11,
from include/linux/pid.h:5,
from include/linux/sched.h:14,
from include/linux/audit.h:12,
from security/apparmor/include/audit.h:14,
from security/apparmor/policy_unpack.c:23:
include/linux/string.h:180:14: note: previous declaration of 'kvmemdup' with type 'void *(const void *, size_t, gfp_t)' {aka 'void *(const void *, unsigned int, unsigned int)'}
180 | extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
| ^~~~~~~~
vim +164 security/apparmor/policy_unpack.c
736ec752d95e91 John Johansen 2010-07-29 163
8e51f9087f4024 Matthew Garrett 2018-02-08 @164 static void *kvmemdup(const void *src, size_t len)
8e51f9087f4024 Matthew Garrett 2018-02-08 165 {
8e51f9087f4024 Matthew Garrett 2018-02-08 166 void *p = kvmalloc(len, GFP_KERNEL);
8e51f9087f4024 Matthew Garrett 2018-02-08 167
8e51f9087f4024 Matthew Garrett 2018-02-08 168 if (p)
8e51f9087f4024 Matthew Garrett 2018-02-08 169 memcpy(p, src, len);
8e51f9087f4024 Matthew Garrett 2018-02-08 170 return p;
8e51f9087f4024 Matthew Garrett 2018-02-08 171 }
8e51f9087f4024 Matthew Garrett 2018-02-08 172
--
0-DAY CI Kernel Test Service
https://01.org/lkp
Hi Hao,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on f9ff5644bcc04221bae56f922122f2b7f5d24d62]
url: https://github.com/intel-lab-lkp/linux/commits/Hao-Sun/mm-new-primitive-kvmemdup/20221219-122348
base: f9ff5644bcc04221bae56f922122f2b7f5d24d62
patch link: https://lore.kernel.org/r/20221219042126.3396-1-sunhao.th%40gmail.com
patch subject: [PATCH] mm: new primitive kvmemdup()
config: x86_64-rhel-8.3
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
reproduce (this is a W=1 build):
# https://github.com/intel-lab-lkp/linux/commit/29c8ee8f5f8fcd8f52aa6912bdb55f3dc135b5a0
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Hao-Sun/mm-new-primitive-kvmemdup/20221219-122348
git checkout 29c8ee8f5f8fcd8f52aa6912bdb55f3dc135b5a0
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=x86_64 olddefconfig
make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
>> security/apparmor/policy_unpack.c:164:14: error: conflicting types for 'kvmemdup'; have 'void *(const void *, size_t)' {aka 'void *(const void *, long unsigned int)'}
164 | static void *kvmemdup(const void *src, size_t len)
| ^~~~~~~~
In file included from include/linux/bitmap.h:11,
from include/linux/cpumask.h:12,
from arch/x86/include/asm/cpumask.h:5,
from arch/x86/include/asm/msr.h:11,
from arch/x86/include/asm/processor.h:23,
from arch/x86/include/asm/cpufeature.h:5,
from arch/x86/include/asm/thread_info.h:53,
from include/linux/thread_info.h:60,
from arch/x86/include/asm/preempt.h:9,
from include/linux/preempt.h:78,
from include/linux/rcupdate.h:27,
from include/linux/rculist.h:11,
from include/linux/pid.h:5,
from include/linux/sched.h:14,
from include/linux/audit.h:12,
from security/apparmor/include/audit.h:14,
from security/apparmor/policy_unpack.c:23:
include/linux/string.h:180:14: note: previous declaration of 'kvmemdup' with type 'void *(const void *, size_t, gfp_t)' {aka 'void *(const void *, long unsigned int, unsigned int)'}
180 | extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
| ^~~~~~~~
vim +164 security/apparmor/policy_unpack.c
736ec752d95e91 John Johansen 2010-07-29 163
8e51f9087f4024 Matthew Garrett 2018-02-08 @164 static void *kvmemdup(const void *src, size_t len)
8e51f9087f4024 Matthew Garrett 2018-02-08 165 {
8e51f9087f4024 Matthew Garrett 2018-02-08 166 void *p = kvmalloc(len, GFP_KERNEL);
8e51f9087f4024 Matthew Garrett 2018-02-08 167
8e51f9087f4024 Matthew Garrett 2018-02-08 168 if (p)
8e51f9087f4024 Matthew Garrett 2018-02-08 169 memcpy(p, src, len);
8e51f9087f4024 Matthew Garrett 2018-02-08 170 return p;
8e51f9087f4024 Matthew Garrett 2018-02-08 171 }
8e51f9087f4024 Matthew Garrett 2018-02-08 172
--
0-DAY CI Kernel Test Service
https://01.org/lkp