| Message ID | 54EE5989.7010800@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 1f8c82ab1b0bc7e24601c0fca411fd27b9c883ef |
| Headers | show |
On Wed, Feb 25, 2015 at 05:23:53PM -0600, Suresh E. Warrier wrote: > Export __spin_yield so that the arch_spin_unlock() function can > be invoked from a module. This will be required for modules where > we want to take a lock that is also is acquired in hypervisor > real mode. Because we want to avoid running any lockdep code > (which may not be safe in real mode), this lock needs to be > an arch_spinlock_t instead of a normal spinlock. > > Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com> Acked-by: Paul Mackerras <paulus@samba.org>
Hi Ben, On Fri, Mar 20, 2015 at 12:08 AM, Paul Mackerras <paulus@samba.org> wrote: > On Wed, Feb 25, 2015 at 05:23:53PM -0600, Suresh E. Warrier wrote: >> Export __spin_yield so that the arch_spin_unlock() function can >> be invoked from a module. This will be required for modules where >> we want to take a lock that is also is acquired in hypervisor >> real mode. Because we want to avoid running any lockdep code >> (which may not be safe in real mode), this lock needs to be >> an arch_spinlock_t instead of a normal spinlock. >> >> Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com> > > Acked-by: Paul Mackerras <paulus@samba.org> Something went wrong when applying this, as it ended up as: commit 1f8c82ab1b0bc7e24601c0fca411fd27b9c883ef Author: Geert Uytterhoeven <geert+renesas@glider.be> Date: Wed Mar 4 12:56:20 2015 +0100 cpufreq/ppc: Add missing #include <asm/smp.h> If CONFIG_SMP=n, <linux/smp.h> does not include <asm/smp.h>, causing: drivers/cpufreq/ppc-corenet-cpufreq.c: In function 'corenet_cpufreq_cpu_init drivers/cpufreq/ppc-corenet-cpufreq.c:173:3: error: implicit declaration of X-Patchwork-Id: 443703 Message-Id: <54EE5989.7010800@linux.vnet.ibm.com> To: linuxppc-dev@ozlabs.org Date: Wed, 25 Feb 2015 17:23:53 -0600 Export __spin_yield so that the arch_spin_unlock() function can be invoked from a module. This will be required for modules where we want to take a lock that is also is acquired in hypervisor real mode. Because we want to avoid running any lockdep code (which may not be safe in real mode), this lock needs to be an arch_spinlock_t instead of a normal spinlock. Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Mon, 2015-03-30 at 12:17 +0200, Geert Uytterhoeven wrote: > Hi Ben, > > On Fri, Mar 20, 2015 at 12:08 AM, Paul Mackerras <paulus@samba.org> wrote: > > On Wed, Feb 25, 2015 at 05:23:53PM -0600, Suresh E. Warrier wrote: > >> Export __spin_yield so that the arch_spin_unlock() function can > >> be invoked from a module. This will be required for modules where > >> we want to take a lock that is also is acquired in hypervisor > >> real mode. Because we want to avoid running any lockdep code > >> (which may not be safe in real mode), this lock needs to be > >> an arch_spinlock_t instead of a normal spinlock. > >> > >> Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com> > > > > Acked-by: Paul Mackerras <paulus@samba.org> > > Something went wrong when applying this, as it ended up as: Ugh, weird. I must have fucked up something when rebasing. I don't want to rebase that branch now that it's out, I know of at least one series based on it. We'll live with it. > commit 1f8c82ab1b0bc7e24601c0fca411fd27b9c883ef > Author: Geert Uytterhoeven <geert+renesas@glider.be> > Date: Wed Mar 4 12:56:20 2015 +0100 > > cpufreq/ppc: Add missing #include <asm/smp.h> > > If CONFIG_SMP=n, <linux/smp.h> does not include <asm/smp.h>, causing: > > drivers/cpufreq/ppc-corenet-cpufreq.c: In function 'corenet_cpufreq_cpu_init > drivers/cpufreq/ppc-corenet-cpufreq.c:173:3: error: implicit declaration of > X-Patchwork-Id: 443703 > Message-Id: <54EE5989.7010800@linux.vnet.ibm.com> > To: linuxppc-dev@ozlabs.org > Date: Wed, 25 Feb 2015 17:23:53 -0600 > > Export __spin_yield so that the arch_spin_unlock() function can > be invoked from a module. This will be required for modules where > we want to take a lock that is also is acquired in hypervisor > real mode. Because we want to avoid running any lockdep code > (which may not be safe in real mode), this lock needs to be > an arch_spinlock_t instead of a normal spinlock. > > Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com> > Acked-by: Paul Mackerras <paulus@samba.org> > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds
diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c index bb7cfec..f31bcee 100644 --- a/arch/powerpc/lib/locks.c +++ b/arch/powerpc/lib/locks.c @@ -41,6 +41,7 @@ void __spin_yield(arch_spinlock_t *lock) plpar_hcall_norets(H_CONFER, get_hard_smp_processor_id(holder_cpu), yield_count); } +EXPORT_SYMBOL_GPL(__spin_yield); /* * Waiting for a read lock or a write lock on a rwlock...
Export __spin_yield so that the arch_spin_unlock() function can be invoked from a module. This will be required for modules where we want to take a lock that is also is acquired in hypervisor real mode. Because we want to avoid running any lockdep code (which may not be safe in real mode), this lock needs to be an arch_spinlock_t instead of a normal spinlock. Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com> --- Replaced export to EXPORT_SYMBOL_GPL Updated commit log to explain what kind of modules will need to use the arch_spin_unlock() function arch/powerpc/lib/locks.c | 1 + 1 file changed, 1 insertion(+)