linux-kernel - [PATCH] docs: deprecated.rst: Update zero-length/one-element arrays section

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Message-ID: <20200901010949.GA21398@embeddedor>
Date:   Mon, 31 Aug 2020 20:09:49 -0500
From:   "Gustavo A. R. Silva" <gustavoars@...nel.org>
To:     Jonathan Corbet <corbet@....net>
Cc:     Kees Cook <keescook@...omium.org>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>
Subject: [PATCH] docs: deprecated.rst: Update zero-length/one-element arrays
 section

Update information in the zero-length and one-element arrays section
and illustrate how to make use of the new flex_array_size() helper,
together with struct_size() and a flexible-array member.

Signed-off-by: Gustavo A. R. Silva <gustavoars@...nel.org>
---
 Documentation/process/deprecated.rst | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst
index 918e32d76fc4..9731704b3f3d 100644
--- a/Documentation/process/deprecated.rst
+++ b/Documentation/process/deprecated.rst
@@ -322,7 +322,8 @@ to allocate for a structure containing an array of this kind as a member::
 In the example above, we had to remember to calculate ``count - 1`` when using
 the struct_size() helper, otherwise we would have --unintentionally-- allocated
 memory for one too many ``items`` objects. The cleanest and least error-prone way
-to implement this is through the use of a `flexible array member`::
+to implement this is through the use of a `flexible array member`, together with
+struct_size() and flex_array_size() helpers::
 
         struct something {
                 size_t count;
@@ -334,5 +335,4 @@ to implement this is through the use of a `flexible array member`::
         instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
         instance->count = count;
 
-        size = sizeof(instance->items[0]) * instance->count;
-        memcpy(instance->items, source, size);
+        memcpy(instance->items, source, flex_array_size(instance, items, instance->count));
-- 
2.27.0