From patchwork Tue Jun 25 20:29:50 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Srivatsa S. 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Bhat" Subject: [PATCH v2 23/45] infiniband: ehca: Use get/put_online_cpus_atomic() to prevent CPU offline To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org, walken@google.com, vincent.guittot@linaro.org, laijs@cn.fujitsu.com Cc: rostedt@goodmis.org, wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com, sbw@mit.edu, fweisbec@gmail.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, linux-pm@vger.kernel.org, linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Hoang-Nam Nguyen , Christoph Raisch , Roland Dreier , Sean Hefty , Hal Rosenstock , linux-rdma@vger.kernel.org, "Srivatsa S. Bhat" Date: Wed, 26 Jun 2013 01:59:50 +0530 Message-ID: <20130625202950.16593.10057.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130625202452.16593.22810.stgit@srivatsabhat.in.ibm.com> References: <20130625202452.16593.22810.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13062520-9574-0000-0000-00000875C0D0 Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org X-Spam-Status: No, score=-8.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Once stop_machine() is gone from the CPU offline path, we won't be able to depend on disabling preemption to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: Hoang-Nam Nguyen Cc: Christoph Raisch Cc: Roland Dreier Cc: Sean Hefty Cc: Hal Rosenstock Cc: linux-rdma@vger.kernel.org Signed-off-by: Srivatsa S. Bhat --- drivers/infiniband/hw/ehca/ehca_irq.c | 5 +++++ 1 file changed, 5 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/infiniband/hw/ehca/ehca_irq.c b/drivers/infiniband/hw/ehca/ehca_irq.c index 8615d7c..ace901e 100644 --- a/drivers/infiniband/hw/ehca/ehca_irq.c +++ b/drivers/infiniband/hw/ehca/ehca_irq.c @@ -43,6 +43,7 @@ #include #include +#include #include "ehca_classes.h" #include "ehca_irq.h" @@ -703,6 +704,7 @@ static void queue_comp_task(struct ehca_cq *__cq) int cq_jobs; unsigned long flags; + get_online_cpus_atomic(); cpu_id = find_next_online_cpu(pool); BUG_ON(!cpu_online(cpu_id)); @@ -720,6 +722,7 @@ static void queue_comp_task(struct ehca_cq *__cq) BUG_ON(!cct || !thread); } __queue_comp_task(__cq, cct, thread); + put_online_cpus_atomic(); } static void run_comp_task(struct ehca_cpu_comp_task *cct) @@ -759,6 +762,7 @@ static void comp_task_park(unsigned int cpu) list_splice_init(&cct->cq_list, &list); spin_unlock_irq(&cct->task_lock); + get_online_cpus_atomic(); cpu = find_next_online_cpu(pool); target = per_cpu_ptr(pool->cpu_comp_tasks, cpu); thread = *per_cpu_ptr(pool->cpu_comp_threads, cpu); @@ -768,6 +772,7 @@ static void comp_task_park(unsigned int cpu) __queue_comp_task(cq, target, thread); } spin_unlock_irq(&target->task_lock); + put_online_cpus_atomic(); } static void comp_task_stop(unsigned int cpu, bool online)