linux-kernel - [tip:x86/entry] x86/entry: Remove unneeded need

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Message-ID: <tip-b5b447b6b4e899e0978b95cb42d272978f8c7b4d@git.kernel.org>
Date:   Fri, 5 Apr 2019 06:13:19 -0700
From:   tip-bot for Valentin Schneider <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, bp@...en8.de, mingo@...nel.org,
        linux-kernel@...r.kernel.org, luto@...nel.org, tglx@...utronix.de,
        valentin.schneider@....com
Subject: [tip:x86/entry] x86/entry: Remove unneeded need_resched() loop

Commit-ID:  b5b447b6b4e899e0978b95cb42d272978f8c7b4d
Gitweb:     https://git.kernel.org/tip/b5b447b6b4e899e0978b95cb42d272978f8c7b4d
Author:     Valentin Schneider <valentin.schneider@....com>
AuthorDate: Mon, 11 Mar 2019 22:47:51 +0000
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Fri, 5 Apr 2019 15:08:03 +0200

x86/entry: Remove unneeded need_resched() loop

Since the enabling and disabling of IRQs within preempt_schedule_irq() is
contained in a need_resched() loop, there is no need for the outer
architecture specific loop.

Signed-off-by: Valentin Schneider <valentin.schneider@....com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Link: https://lkml.kernel.org/r/20190311224752.8337-14-valentin.schneider@arm.com

---
 arch/x86/entry/entry_32.S | 3 +--
 arch/x86/entry/entry_64.S | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index d309f30cf7af..b1856fe9decf 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -766,13 +766,12 @@ END(ret_from_exception)
 #ifdef CONFIG_PREEMPT
 ENTRY(resume_kernel)
 	DISABLE_INTERRUPTS(CLBR_ANY)
-.Lneed_resched:
 	cmpl	$0, PER_CPU_VAR(__preempt_count)
 	jnz	restore_all_kernel
 	testl	$X86_EFLAGS_IF, PT_EFLAGS(%esp)	# interrupts off (exception path) ?
 	jz	restore_all_kernel
 	call	preempt_schedule_irq
-	jmp	.Lneed_resched
+	jmp	restore_all_kernel
 END(resume_kernel)
 #endif
 
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 1f0efdb7b629..e7e270603fe7 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -645,10 +645,9 @@ retint_kernel:
 	/* Check if we need preemption */
 	btl	$9, EFLAGS(%rsp)		/* were interrupts off? */
 	jnc	1f
-0:	cmpl	$0, PER_CPU_VAR(__preempt_count)
+	cmpl	$0, PER_CPU_VAR(__preempt_count)
 	jnz	1f
 	call	preempt_schedule_irq
-	jmp	0b
 1:
 #endif
 	/*