Re: [dpdk-dev] [PATCH v9] eal: remove sys/queue.h from public headers

[David Marchand <david.marchand@redhat.com>]

Hello William,

On Fri, Oct 1, 2021 at 12:17 AM William Tu <u9012063@gmail.com> wrote:
>
> On Mon, Sep 20, 2021 at 1:11 PM Narcisa Ana Maria Vasile
> <navasile@linux.microsoft.com> wrote:
> >
> > On Tue, Aug 24, 2021 at 04:21:03PM +0000, William Tu wrote:
> > > Currently there are some public headers that include 'sys/queue.h', which
> > > is not POSIX, but usually provided by the Linux/BSD system library.
> > > (Not in POSIX.1, POSIX.1-2001, or POSIX.1-2008. Present on the BSDs.)
> > > The file is missing on Windows. During the Windows build, DPDK uses a
> > > bundled copy, so building a DPDK library works fine.  But when OVS or other
> > > applications use DPDK as a library, because some DPDK public headers
> > > include 'sys/queue.h', on Windows, it triggers an error due to no such
> > > file.
> > >
> > > One solution is to install the 'lib/eal/windows/include/sys/queue.h' into
> > > Windows environment, such as [1]. However, this means DPDK exports the
> > > functionalities of 'sys/queue.h' into the environment, which might cause
> > > symbols, macros, headers clashing with other applications.
> > >
> > > The patch fixes it by removing the "#include <sys/queue.h>" from
> > > DPDK public headers, so programs including DPDK headers don't depend
> > > on the system to provide 'sys/queue.h'. When these public headers use
> > > macros such as TAILQ_xxx, we replace it by the ones with RTE_ prefix.
> > > For Windows, we copy the definitions from <sys/queue.h> to rte_os.h
> > > in Windows EAL. Note that these RTE_ macros are compatible with
> > > <sys/queue.h>, both at the level of API (to use with <sys/queue.h>
> > > macros in C files) and ABI (to avoid breaking it).
> > >
> > > Additionally, the TAILQ_FOREACH_SAFE is not part of <sys/queue.h>,
> > > the patch replaces it with RTE_TAILQ_FOREACH_SAFE.
> > >
> > > [1] http://mails.dpdk.org/archives/dev/2021-August/216304.html
> > >
> > > Suggested-by: Nick Connolly <nick.connolly@mayadata.io>
> > > Suggested-by: Dmitry Kozliuk <Dmitry.Kozliuk@gmail.com>
> > > Acked-by: Dmitry Kozliuk <Dmitry.Kozliuk@gmail.com>
> > > Signed-off-by: William Tu <u9012063@gmail.com>
> > > ---
> > Acked-by: Narcisa Vasile <navasile@linux.microsoft.com>
> Hi Thomas,
> Ping to see if the patch can be applied?

$ grep -rE '\<(|S)(CIRCLEQ|LIST|SIMPLEQ|TAILQ)_' build/install/include/
build/install/include/rte_tailq.h: *   first parameter passed to
TAILQ_HEAD macro)
build/install/include/rte_crypto_sym.h: * - LIST_END should not be
added to this enum
build/install/include/rte_crypto_sym.h: * - LIST_END should not be
added to this enum
build/install/include/rte_crypto_sym.h: * - LIST_END should not be
added to this enum
build/install/include/rte_os.h:#define RTE_TAILQ_HEAD(name, type)
TAILQ_HEAD(name, type)
build/install/include/rte_os.h:#define RTE_TAILQ_ENTRY(type) TAILQ_ENTRY(type)
build/install/include/rte_os.h:#define RTE_TAILQ_FOREACH(var, head,
field) TAILQ_FOREACH(var, head, field)
build/install/include/rte_os.h:#define RTE_TAILQ_FIRST(head) TAILQ_FIRST(head)
build/install/include/rte_os.h:#define RTE_TAILQ_NEXT(elem, field)
TAILQ_NEXT(elem, field)
build/install/include/rte_os.h:#define RTE_STAILQ_HEAD(name, type)
STAILQ_HEAD(name, type)
build/install/include/rte_os.h:#define RTE_STAILQ_ENTRY(type) STAILQ_ENTRY(type)

LGTM.

I just have a concern that headers get broken again if we have no check.
Could buildtools/chkincs do the job (if we make this check work on Windows)?


-- 
David Marchand