From 74a622be3db2898251cb524d1edbeaea589f2723 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 28 Feb 2012 19:46:05 +0000 Subject: ia64: vsyscall: Use seqcount instead of seqlock The update of the vdso data happens under xtime_lock, so adding a nested lock is pointless. Just use a seqcount to sync the readers. Signed-off-by: Thomas Gleixner Cc: Tony Luck Signed-off-by: John Stultz --- arch/ia64/kernel/asm-offsets.c | 4 ++-- arch/ia64/kernel/fsys.S | 2 +- arch/ia64/kernel/fsyscall_gtod_data.h | 2 +- arch/ia64/kernel/time.c | 10 +++------- 4 files changed, 7 insertions(+), 11 deletions(-) diff --git a/arch/ia64/kernel/asm-offsets.c b/arch/ia64/kernel/asm-offsets.c index af565016904..106aeb670e5 100644 --- a/arch/ia64/kernel/asm-offsets.c +++ b/arch/ia64/kernel/asm-offsets.c @@ -269,8 +269,8 @@ void foo(void) BLANK(); /* used by fsys_gettimeofday in arch/ia64/kernel/fsys.S */ - DEFINE(IA64_GTOD_LOCK_OFFSET, - offsetof (struct fsyscall_gtod_data_t, lock)); + DEFINE(IA64_GTOD_SEQ_OFFSET, + offsetof (struct fsyscall_gtod_data_t, seq); DEFINE(IA64_GTOD_WALL_TIME_OFFSET, offsetof (struct fsyscall_gtod_data_t, wall_time)); DEFINE(IA64_GTOD_MONO_TIME_OFFSET, diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S index 331d42bda77..fa77de7032b 100644 --- a/arch/ia64/kernel/fsys.S +++ b/arch/ia64/kernel/fsys.S @@ -174,7 +174,7 @@ ENTRY(fsys_set_tid_address) FSYS_RETURN END(fsys_set_tid_address) -#if IA64_GTOD_LOCK_OFFSET !=0 +#if IA64_GTOD_SEQ_OFFSET !=0 #error fsys_gettimeofday incompatible with changes to struct fsyscall_gtod_data_t #endif #if IA64_ITC_JITTER_OFFSET !=0 diff --git a/arch/ia64/kernel/fsyscall_gtod_data.h b/arch/ia64/kernel/fsyscall_gtod_data.h index 57d2ee6c83e..146b15b5fec 100644 --- a/arch/ia64/kernel/fsyscall_gtod_data.h +++ b/arch/ia64/kernel/fsyscall_gtod_data.h @@ -6,7 +6,7 @@ */ struct fsyscall_gtod_data_t { - seqlock_t lock; + seqcount_t seq; struct timespec wall_time; struct timespec monotonic_time; cycle_t clk_mask; diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c index 43920de425f..8e991a0b5e3 100644 --- a/arch/ia64/kernel/time.c +++ b/arch/ia64/kernel/time.c @@ -35,9 +35,7 @@ static cycle_t itc_get_cycles(struct clocksource *cs); -struct fsyscall_gtod_data_t fsyscall_gtod_data = { - .lock = __SEQLOCK_UNLOCKED(fsyscall_gtod_data.lock), -}; +struct fsyscall_gtod_data_t fsyscall_gtod_data; struct itc_jitter_data_t itc_jitter_data; @@ -460,9 +458,7 @@ void update_vsyscall_tz(void) void update_vsyscall(struct timespec *wall, struct timespec *wtm, struct clocksource *c, u32 mult) { - unsigned long flags; - - write_seqlock_irqsave(&fsyscall_gtod_data.lock, flags); + write_seqcount_begin(&fsyscall_gtod_data.seq); /* copy fsyscall clock data */ fsyscall_gtod_data.clk_mask = c->mask; @@ -485,6 +481,6 @@ void update_vsyscall(struct timespec *wall, struct timespec *wtm, fsyscall_gtod_data.monotonic_time.tv_sec++; } - write_sequnlock_irqrestore(&fsyscall_gtod_data.lock, flags); + write_seqcount_end(&fsyscall_gtod_data.seq); } -- cgit v1.2.3