[tip:sched/core] sched, net: Clean up preempt_enable_no_resched() abuse

[tip-bot for Peter Zijlstra]

Commit-ID:  1774e9f3e5c8b38de3b3bc8bd0eacd280f655baf
Gitweb:     http://git.kernel.org/tip/1774e9f3e5c8b38de3b3bc8bd0eacd280f655baf
Author:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Tue, 19 Nov 2013 16:13:38 +0100
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 13 Jan 2014 17:39:04 +0100

sched, net: Clean up preempt_enable_no_resched() abuse

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'.

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: rjw@xxxxxxxxxxxxx
Cc: Eliezer Tamir <eliezer.tamir@xxxxxxxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: rui.zhang@xxxxxxxxx
Cc: jacob.jun.pan@xxxxxxxxxxxxxxx
Cc: Mike Galbraith <bitbucket@xxxxxxxxx>
Cc: hpa@xxxxxxxxx
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Cc: lenb@xxxxxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20131119151338.GF3694@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 net/ipv4/tcp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index c4638e6..82de786 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1623,11 +1623,11 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 		    (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
--
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