On Wed, May 08, 2013 at 08:45:24PM +0200, Borislav Petkov wrote:
> On Wed, May 08, 2013 at 12:12:32PM -0400, Naoya Horiguchi wrote:
> > Thank you for the report.
> > I believe we can fix it with this one.
> > ---
> > From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> > Date: Wed, 8 May 2013 11:48:01 -0400
> > Subject: [PATCH] ipc/shm.c: don't use auto variable hs in newseg()
> >
> > This patch fixes "warning: unused variable 'hs'" when !CONFIG_HUGETLB_PAGE
> > introduced by commit af73e4d9506d "hugetlbfs: fix mmap failure in unaligned
> > size request".
> >
> > Reported-by: Borislav Petkov <bp@xxxxxxxxx>
> > Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> > ---
> > ipc/shm.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/ipc/shm.c b/ipc/shm.c
> > index e316cb9..9ff741a 100644
> > --- a/ipc/shm.c
> > +++ b/ipc/shm.c
> > @@ -491,9 +491,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
> >
> > sprintf (name, "SYSV%08x", key);
> > if (shmflg & SHM_HUGETLB) {
> > - struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT)
> > - & SHM_HUGE_MASK);
> > - size_t hugesize = ALIGN(size, huge_page_size(hs));
> > + size_t hugesize = ALIGN(size, huge_page_size(hstate_sizelog(
> > + (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK)));
>
> Yeah, it fixes the warning alright but makes the code more unreadable.
> Which makes me wonder which is worse - to have an innocuous warning or
> have unreadable code.
>
> You could also do the below. The line sticks out but it kills the
> warning. Readability is hmm, not optimal still though. :)
> --
> diff --git a/ipc/shm.c b/ipc/shm.c
> --- a/ipc/shm.c
> +++ b/ipc/shm.c
> @@ -491,9 +491,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
>
> sprintf (name, "SYSV%08x", key);
> if (shmflg & SHM_HUGETLB) {
> - struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT)
> - & SHM_HUGE_MASK);
> - size_t hugesize = ALIGN(size, huge_page_size(hs));
> + unsigned long hsz = huge_page_size(hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK));
> + size_t hugesize = ALIGN(size, hsz);
>
> /* hugetlb_file_setup applies strict accounting */
> if (shmflg & SHM_NORESERVE)
> --
>
> Yeah, you decide.
(CCed: Andrew and linux-mm)
OK, personally both are OK (comparably bad) for me, so I'll do the same
as af73e4d9506d3b does for SYSCALL_DEFINE6(mmap_pgoff), where we have
a line break just after '('.
Andrew, could you pick up the following fix?
-----
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Date: Wed, 8 May 2013 11:48:01 -0400
Subject: [PATCH] ipc/shm.c: don't use auto variable hs in newseg()
This patch fixes "warning: unused variable 'hs'" when !CONFIG_HUGETLB_PAGE
introduced by commit af73e4d9506d "hugetlbfs: fix mmap failure in unaligned
size request".
Reported-by: Borislav Petkov <bp@xxxxxxxxx>
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
---
ipc/shm.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/ipc/shm.c b/ipc/shm.c
index e316cb9..9ff741a 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -491,9 +491,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
sprintf (name, "SYSV%08x", key);
if (shmflg & SHM_HUGETLB) {
- struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT)
- & SHM_HUGE_MASK);
- size_t hugesize = ALIGN(size, huge_page_size(hs));
+ size_t hugesize = ALIGN(size, huge_page_size(hstate_sizelog(
+ (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK)));
/* hugetlb_file_setup applies strict accounting */
if (shmflg & SHM_NORESERVE)
--
1.7.11.7
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