From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH RT 09/25][RFC 3.0.23-rt39-rc1] ia64: vsyscall: Use seqcount instead of seqlock Date: Tue, 06 Mar 2012 11:16:45 -0500 Message-ID: <20120306161946.789821696@goodmis.org> References: <20120306161636.491172179@goodmis.org> Cc: Thomas Gleixner , Carsten Emde , John Kacur , Tony Luck , stable-rt@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-rt-users Return-path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:32910 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755534Ab2CFQTs (ORCPT ); Tue, 6 Mar 2012 11:19:48 -0500 Content-Disposition: inline; filename=0009-ia64-vsyscall-Use-seqcount-instead-of-seqlock.patch Sender: linux-rt-users-owner@vger.kernel.org List-ID: From: Thomas Gleixner 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 Cc: stable-rt@vger.kernel.org Signed-off-by: Steven Rostedt --- 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 af56501..106aeb6 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 331d42b..fa77de7 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 57d2ee6..146b15b 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 85118df..15823ed 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;