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From: Peter Zijlstra <peterz@infradead.org>
To: Arjan van de Ven <arjan@linux.intel.com>,
	lenb@kernel.org, rjw@rjwysocki.net,
	Eliezer Tamir <eliezer.tamir@linux.intel.com>,
	David Miller <davem@davemloft.net>,
	rui.zhang@intel.com, jacob.jun.pan@linux.intel.com,
	Mike Galbraith <bitbucket@online.de>,
	Ingo Molnar <mingo@kernel.org>,
	hpa@zytor.com, Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Subject: [PATCH 6/8] sched, net: Clean up preempt_enable_no_resched() abuse
Date: Tue, 26 Nov 2013 16:57:49 +0100	[thread overview]
Message-ID: <20131126160815.225776365@infradead.org> (raw)
In-Reply-To: 20131126155743.116756708@infradead.org

[-- Attachment #1: peterz-fixup-weird-preempt_enable_no_resched-usage.patch --]
[-- Type: text/plain, Size: 1171 bytes --]

The only valid use of preempt_enable_no_resched() is if the very next
line is schedule() or if we know preemption cannot actually be enabled
by that statement due to known more preempt_count 'refs'.

Cc: rjw@rjwysocki.net
Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: rui.zhang@intel.com
Cc: jacob.jun.pan@linux.intel.com
Cc: Mike Galbraith <bitbucket@online.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: hpa@zytor.com
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: lenb@kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
---
 net/ipv4/tcp.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1623,11 +1623,11 @@ int tcp_recvmsg(struct kiocb *iocb, stru
 		    (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
 		    !sysctl_tcp_low_latency &&
 		    net_dma_find_channel()) {
-			preempt_enable_no_resched();
+			preempt_enable();
 			tp->ucopy.pinned_list =
 					dma_pin_iovec_pages(msg->msg_iov, len);
 		} else {
-			preempt_enable_no_resched();
+			preempt_enable();
 		}
 	}
 #endif



  parent reply	other threads:[~2013-11-26 16:11 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-26 15:57 [PATCH 0/8] Cure faux idle wreckage Peter Zijlstra
2013-11-26 15:57 ` [PATCH 1/8] x86, acpi, idle: Restructure the mwait idle routines Peter Zijlstra
2013-11-26 15:57 ` [PATCH 2/8] sched, preempt: Fixup missed PREEMPT_NEED_RESCHED folding Peter Zijlstra
2013-11-26 15:57 ` [PATCH 3/8] idle, thermal, acpi: Remove home grown idle implementations Peter Zijlstra
2013-11-26 15:57 ` [PATCH 4/8] preempt, locking: Rework local_bh_{dis,en}able() Peter Zijlstra
2013-11-26 15:57 ` [PATCH 5/8] locking: Optimize lock_bh functions Peter Zijlstra
2013-11-26 15:57 ` Peter Zijlstra [this message]
2013-11-26 15:57 ` [PATCH 7/8] sched, net: Fixup busy_loop_us_clock() Peter Zijlstra
2013-11-28 16:49   ` Eliezer Tamir
2013-11-28 17:40     ` Peter Zijlstra
2013-11-28 18:50       ` Peter Zijlstra
2013-11-29 13:52       ` Eliezer Tamir
2013-11-26 15:57 ` [PATCH 8/8] preempt: Take away preempt_enable_no_resched() from modules Peter Zijlstra
2013-11-26 23:23 ` [PATCH 0/8] Cure faux idle wreckage Jacob Pan

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