RE: [PATCH 11/31] nds32: Atomic operations

-----Original Message-----
From: arndbergmann@gmail.com [mailto:arndbergmann@gmail.com] On
Behalf Of Arnd Bergmann
Sent: Wednesday, November 08, 2017 4:54 PM
To: Greentime Hu
Cc: Greentime Ying-Han Hu(胡英漢); Linux Kernel Mailing List; linux-arch;
Thomas Gleixner; Jason Cooper; Marc Zyngier; Rob Herring; Networking;
Vincent Ren-Wei Chen(陳人維); Palmer Dabbelt
Subject: Re: [PATCH 11/31] nds32: Atomic operations

On Wed, Nov 8, 2017 at 6:54 AM, Greentime Hu [off-list ref]
wrote:

quoted

From: Greentime Hu <redacted>

Signed-off-by: Vincent Chen <redacted>
Signed-off-by: Greentime Hu <redacted>
---
 arch/nds32/include/asm/futex.h    |  116 ++++++++++++++++++++++++
 arch/nds32/include/asm/spinlock.h |  178
+++++++++++++++++++++++++++++++++++++
 2 files changed, 294 insertions(+)
 create mode 100644 arch/nds32/include/asm/futex.h  create mode

100644

quoted

arch/nds32/include/asm/spinlock.h

quoted

diff --git a/arch/nds32/include/asm/spinlock.h

b/arch/nds32/include/asm/spinlock.h
new file mode 100644
index 0000000..dd5fc71

--- /dev/null
+++ b/arch/nds32/include/asm/spinlock.h

@@ -0,0 +1,178 @@
+
+#define arch_spin_unlock_wait(lock) \
+       do { while (arch_spin_is_locked(lock)) cpu_relax(); } while
+(0)

This was removed from the other architectures in commit
952111d7db02 ("arch: Remove spin_unlock_wait() arch-specific definitions")

Please remove this as well.

Dear Arnd:

I will remove them in the next version patch.

Palmer, I see riscv has the same thing, please also add a patch to your tree to
remove it.

quoted

+#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
+
+static inline void arch_spin_lock(arch_spinlock_t * lock) {
+       unsigned long tmp;
+
+       __asm__ __volatile__("1:\n"
+                            "\tllw\t%0, [%1]\n"
+                            "\tbnez\t%0, 1b\n"
+                            "\tmovi\t%0, #0x1\n"
+                            "\tscw\t%0, [%1]\n"
+                            "\tbeqz\t%0, 1b\n"
+                            :"=&r"(tmp)
+                            :"r"(&lock->lock)
+                            :"memory");

The coding style seems inconsistent here, the other inline asm uses real tabs
instead of \t, and 'asm volatile' is generally preferred over '__asm__
__volatile__'.

       Arnd

OK, I will modify it in the next version patch.

Thanks

Best regards
Vincent
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