From 84292b29475bc7bb6b04ae5360595bd816ca4efb Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 21 Oct 2013 13:25:36 +0200 Subject: percpu: remove this_cpu_xor() implementation There is not a single user in the whole kernel. Besides that this_cpu_xor() is broken anyway since it gets translated to this_cpu_or() (see __pcpu_size_call() line). So instead of fixing an unused definition just remove it. Signed-off-by: Heiko Carstens Acked-by: Ingo Molnar Signed-off-by: Tejun Heo --- include/linux/percpu.h | 32 -------------------------------- 1 file changed, 32 deletions(-) (limited to 'include/linux/percpu.h') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index cc88172c7d9a..fd6ffe459aae 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -375,22 +375,6 @@ do { \ # define this_cpu_or(pcp, val) __pcpu_size_call(this_cpu_or_, (pcp), (val)) #endif -#ifndef this_cpu_xor -# ifndef this_cpu_xor_1 -# define this_cpu_xor_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=) -# endif -# ifndef this_cpu_xor_2 -# define this_cpu_xor_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=) -# endif -# ifndef this_cpu_xor_4 -# define this_cpu_xor_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=) -# endif -# ifndef this_cpu_xor_8 -# define this_cpu_xor_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=) -# endif -# define this_cpu_xor(pcp, val) __pcpu_size_call(this_cpu_or_, (pcp), (val)) -#endif - #define _this_cpu_generic_add_return(pcp, val) \ ({ \ typeof(pcp) ret__; \ @@ -629,22 +613,6 @@ do { \ # define __this_cpu_or(pcp, val) __pcpu_size_call(__this_cpu_or_, (pcp), (val)) #endif -#ifndef __this_cpu_xor -# ifndef __this_cpu_xor_1 -# define __this_cpu_xor_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=) -# endif -# ifndef __this_cpu_xor_2 -# define __this_cpu_xor_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=) -# endif -# ifndef __this_cpu_xor_4 -# define __this_cpu_xor_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=) -# endif -# ifndef __this_cpu_xor_8 -# define __this_cpu_xor_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=) -# endif -# define __this_cpu_xor(pcp, val) __pcpu_size_call(__this_cpu_xor_, (pcp), (val)) -#endif - #define __this_cpu_generic_add_return(pcp, val) \ ({ \ __this_cpu_add(pcp, val); \ -- cgit v1.2.2 From bd09d9a35111b6ffc0c7585d3853d0ec7f9f1eb4 Mon Sep 17 00:00:00 2001 From: Greg Thelen Date: Wed, 30 Oct 2013 13:56:20 -0700 Subject: percpu: fix this_cpu_sub() subtrahend casting for unsigneds this_cpu_sub() is implemented as negation and addition. This patch casts the adjustment to the counter type before negation to sign extend the adjustment. This helps in cases where the counter type is wider than an unsigned adjustment. An alternative to this patch is to declare such operations unsupported, but it seemed useful to avoid surprises. This patch specifically helps the following example: unsigned int delta = 1 preempt_disable() this_cpu_write(long_counter, 0) this_cpu_sub(long_counter, delta) preempt_enable() Before this change long_counter on a 64 bit machine ends with value 0xffffffff, rather than 0xffffffffffffffff. This is because this_cpu_sub(pcp, delta) boils down to this_cpu_add(pcp, -delta), which is basically: long_counter = 0 + 0xffffffff Also apply the same cast to: __this_cpu_sub() __this_cpu_sub_return() this_cpu_sub_return() All percpu_test.ko passes, especially the following cases which previously failed: l -= ui_one; __this_cpu_sub(long_counter, ui_one); CHECK(l, long_counter, -1); l -= ui_one; this_cpu_sub(long_counter, ui_one); CHECK(l, long_counter, -1); CHECK(l, long_counter, 0xffffffffffffffff); ul -= ui_one; __this_cpu_sub(ulong_counter, ui_one); CHECK(ul, ulong_counter, -1); CHECK(ul, ulong_counter, 0xffffffffffffffff); ul = this_cpu_sub_return(ulong_counter, ui_one); CHECK(ul, ulong_counter, 2); ul = __this_cpu_sub_return(ulong_counter, ui_one); CHECK(ul, ulong_counter, 1); Signed-off-by: Greg Thelen Acked-by: Tejun Heo Acked-by: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/percpu.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux/percpu.h') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index cc88172c7d9a..c74088ab103b 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -332,7 +332,7 @@ do { \ #endif #ifndef this_cpu_sub -# define this_cpu_sub(pcp, val) this_cpu_add((pcp), -(val)) +# define this_cpu_sub(pcp, val) this_cpu_add((pcp), -(typeof(pcp))(val)) #endif #ifndef this_cpu_inc @@ -418,7 +418,7 @@ do { \ # define this_cpu_add_return(pcp, val) __pcpu_size_call_return2(this_cpu_add_return_, pcp, val) #endif -#define this_cpu_sub_return(pcp, val) this_cpu_add_return(pcp, -(val)) +#define this_cpu_sub_return(pcp, val) this_cpu_add_return(pcp, -(typeof(pcp))(val)) #define this_cpu_inc_return(pcp) this_cpu_add_return(pcp, 1) #define this_cpu_dec_return(pcp) this_cpu_add_return(pcp, -1) @@ -586,7 +586,7 @@ do { \ #endif #ifndef __this_cpu_sub -# define __this_cpu_sub(pcp, val) __this_cpu_add((pcp), -(val)) +# define __this_cpu_sub(pcp, val) __this_cpu_add((pcp), -(typeof(pcp))(val)) #endif #ifndef __this_cpu_inc @@ -668,7 +668,7 @@ do { \ __pcpu_size_call_return2(__this_cpu_add_return_, pcp, val) #endif -#define __this_cpu_sub_return(pcp, val) __this_cpu_add_return(pcp, -(val)) +#define __this_cpu_sub_return(pcp, val) __this_cpu_add_return(pcp, -(typeof(pcp))(val)) #define __this_cpu_inc_return(pcp) __this_cpu_add_return(pcp, 1) #define __this_cpu_dec_return(pcp) __this_cpu_add_return(pcp, -1) -- cgit v1.2.2