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Sun, 18 Dec 2022 20:21:55 -0800 (PST) From: Hao Sun To: linux-mm@kvack.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Cc: daniel@iogearbox.net, Hao Sun Subject: [PATCH] mm: new primitive kvmemdup() Date: Mon, 19 Dec 2022 12:21:26 +0800 Message-Id: <20221219042126.3396-1-sunhao.th@gmail.com> X-Mailer: git-send-email 2.37.1 (Apple Git-137.1) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 11AADA0002 X-Stat-Signature: irpo3bu7u68nbcifwjzt38mtkxphc4nj X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1671423717-613175 X-HE-Meta: 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 8jtBsyxG 0ZTo4JfDD7nN/NowCrJ2IhtsRPPY7DWXXyumcvcHJwTiZKHAJ7Rgtrl+kGq7mPiLPZXy2Az8JaKCjsP15XeUphMABM8tver5xjJ16zSRENQ8t4fNf01hwi9cT5xupVARQFClIWpQGEg3xe/1sT7U41N9KOiH4dsucSYw9kMR6n9+9Aub9g9C/vLkldPQ6uUP5Pxlw/WV8qOOOr4gpA9IpK2YMLqczOJPb5/dkdtwCxYg/lJA= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000010, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 Signed-off-by: Hao Sun --- 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/7d274284-0fcc-061c-582e-3dfb629c6a44@iogearbox.net/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