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18c25b4019
list_for_each_entry{_safe} is able to handle an empty list.
The only effect of avoiding the loop is not initializing the
index variable.
Drop list_empty tests in cases where these variables are not
used.
Note that list_for_each_entry{_safe} is defined in terms of
list_first_entry, which indicates that it should not be used on an
empty list. But in list_for_each_entry{_safe}, the element obtained
by list_first_entry is not really accessed, only the address of its
list_head field is compared to the address of the list head, so the
list_first_entry is safe.
The semantic patch that makes this change for the list_for_each_entry
case is as follows: (http://coccinelle.lip6.fr/)
<smpl>
@@
expression x,e;
statement S;
identifier i;
@@
-if (!(list_empty(x)))
list_for_each_entry(i,x,...) S
... when != i
? i = e
</smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1595761112-11003-8-git-send-email-Julia.Lawall@inria.fr
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.