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AJvYcCXlu0IccO01YPRQf3xebcWFOTYhlSnwI8pKOtfuCEVKeCbHHOKyitNiS/Y1ug8v/8FGpwvDOX+EhrCXa6S8kwe42fMBq1SjgFAR09oYktsAReh1LueFGK/IV23S2qOZdaGzjTJip9oQzGkNGqwmPk3744IbJ8N+I7rz5TDxFO+EJcMMNldOeZWPQMA+R4RlTSmMsJMVpc4MPoDvH3PpjJzmammQ3HrsPqqbfdbyOBCFQ4+gjb+dqvI5Jr6ysETgVtKfB33/QiEHD4URV6/AwPSVcU1mOqmn1xFhHdEFULsY2/kHU4GsuvERVu1urU+BW00sRAucrA== X-Gm-Message-State: AOJu0Yx3EICn6/LCxZEiWKZWN1ek6yv7XL1KLYmJVxsn4QKcuriFnEfn TTjGFtTLuUnFVqsNa8DjNog06b4/PSwedW3VyW5HXfIgwuh7PQvm9w6c05tagzM= X-Google-Smtp-Source: AGHT+IEL7YdwJrnU7j+3S0kOHwdlHJumXPs1OdWAsSouquvh+afE8cHfhlG2TFnMxzOYJRDIWJjJ4Q== X-Received: by 2002:a17:902:e549:b0:202:100f:7b9b with SMTP id d9443c01a7336-202100f7d6amr36403685ad.35.1723863461337; Fri, 16 Aug 2024 19:57:41 -0700 (PDT) Received: from localhost.localdomain ([183.193.177.10]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-201f031c5e1sm31801785ad.94.2024.08.16.19.57.32 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Aug 2024 19:57:40 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org, alx@kernel.org, justinstitt@google.com, ebiederm@xmission.com, alexei.starovoitov@gmail.com, rostedt@goodmis.org, catalin.marinas@arm.com, penguin-kernel@i-love.sakura.ne.jp, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, audit@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Yafang Shao , Simon Horman , Matthew Wilcox Subject: [PATCH v7 6/8] mm/util: Deduplicate code in {kstrdup,kstrndup,kmemdup_nul} Date: Sat, 17 Aug 2024 10:56:22 +0800 Message-Id: <20240817025624.13157-7-laoar.shao@gmail.com> X-Mailer: git-send-email 2.30.1 (Apple Git-130) In-Reply-To: <20240817025624.13157-1-laoar.shao@gmail.com> References: <20240817025624.13157-1-laoar.shao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 These three functions follow the same pattern. To deduplicate the code, let's introduce a common helper __kmemdup_nul(). Suggested-by: Andrew Morton Signed-off-by: Yafang Shao Cc: Simon Horman Cc: Matthew Wilcox --- mm/util.c | 67 +++++++++++++++++++++---------------------------------- 1 file changed, 26 insertions(+), 41 deletions(-) diff --git a/mm/util.c b/mm/util.c index 4542d8a800d9..310c7735c617 100644 --- a/mm/util.c +++ b/mm/util.c @@ -45,33 +45,40 @@ void kfree_const(const void *x) EXPORT_SYMBOL(kfree_const); /** - * kstrdup - allocate space for and copy an existing string - * @s: the string to duplicate + * __kmemdup_nul - Create a NUL-terminated string from @s, which might be unterminated. + * @s: The data to copy + * @len: The size of the data, including the null terminator * @gfp: the GFP mask used in the kmalloc() call when allocating memory * - * Return: newly allocated copy of @s or %NULL in case of error + * Return: newly allocated copy of @s with NUL-termination or %NULL in + * case of error */ -noinline -char *kstrdup(const char *s, gfp_t gfp) +static __always_inline char *__kmemdup_nul(const char *s, size_t len, gfp_t gfp) { - size_t len; char *buf; - if (!s) + buf = kmalloc_track_caller(len, gfp); + if (!buf) return NULL; - len = strlen(s) + 1; - buf = kmalloc_track_caller(len, gfp); - if (buf) { - memcpy(buf, s, len); - /* During memcpy(), the string might be updated to a new value, - * which could be longer than the string when strlen() is - * called. Therefore, we need to add a null termimator. - */ - buf[len - 1] = '\0'; - } + memcpy(buf, s, len); + /* Ensure the buf is always NUL-terminated, regardless of @s. */ + buf[len - 1] = '\0'; return buf; } + +/** + * kstrdup - allocate space for and copy an existing string + * @s: the string to duplicate + * @gfp: the GFP mask used in the kmalloc() call when allocating memory + * + * Return: newly allocated copy of @s or %NULL in case of error + */ +noinline +char *kstrdup(const char *s, gfp_t gfp) +{ + return s ? __kmemdup_nul(s, strlen(s) + 1, gfp) : NULL; +} EXPORT_SYMBOL(kstrdup); /** @@ -106,19 +113,7 @@ EXPORT_SYMBOL(kstrdup_const); */ char *kstrndup(const char *s, size_t max, gfp_t gfp) { - size_t len; - char *buf; - - if (!s) - return NULL; - - len = strnlen(s, max); - buf = kmalloc_track_caller(len+1, gfp); - if (buf) { - memcpy(buf, s, len); - buf[len] = '\0'; - } - return buf; + return s ? __kmemdup_nul(s, strnlen(s, max) + 1, gfp) : NULL; } EXPORT_SYMBOL(kstrndup); @@ -192,17 +187,7 @@ EXPORT_SYMBOL(kvmemdup); */ char *kmemdup_nul(const char *s, size_t len, gfp_t gfp) { - char *buf; - - if (!s) - return NULL; - - buf = kmalloc_track_caller(len + 1, gfp); - if (buf) { - memcpy(buf, s, len); - buf[len] = '\0'; - } - return buf; + return s ? __kmemdup_nul(s, len + 1, gfp) : NULL; } EXPORT_SYMBOL(kmemdup_nul);