Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932367AbaJ1Dnf (ORCPT ); Mon, 27 Oct 2014 23:43:35 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45169 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755304AbaJ1Dnb (ORCPT ); Mon, 27 Oct 2014 23:43:31 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "K. Y. Srinivasan" , Sitsofe Wheeler Subject: [PATCH 3.16 042/127] Drivers: hv: vmbus: Cleanup hv_post_message() Date: Tue, 28 Oct 2014 11:34:37 +0800 Message-Id: <20141028033422.751280272@linuxfoundation.org> X-Mailer: git-send-email 2.1.2 In-Reply-To: <20141028033420.925922046@linuxfoundation.org> References: <20141028033420.925922046@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: "K. Y. Srinivasan" commit b29ef3546aecb253a5552b198cef23750d56e1e4 upstream. Minimize failures in this function by pre-allocating the buffer for posting messages. The hypercall for posting the message can fail for a number of reasons: 1. Transient resource related issues 2. Buffer alignment 3. Buffer cannot span a page boundry We address issues 2 and 3 by preallocating a per-cpu page for the buffer. Transient resource related failures are handled by retrying by the callers of this function. This patch is based on the investigation done by Dexuan Cui . I would like to thank Sitsofe Wheeler for reporting the issue and helping in debuggging. Signed-off-by: K. Y. Srinivasan Reported-by: Sitsofe Wheeler Tested-by: Sitsofe Wheeler Signed-off-by: Greg Kroah-Hartman --- drivers/hv/hv.c | 27 +++++++++++++++------------ drivers/hv/hyperv_vmbus.h | 4 ++++ 2 files changed, 19 insertions(+), 12 deletions(-) --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -138,6 +138,8 @@ int hv_init(void) memset(hv_context.synic_event_page, 0, sizeof(void *) * NR_CPUS); memset(hv_context.synic_message_page, 0, sizeof(void *) * NR_CPUS); + memset(hv_context.post_msg_page, 0, + sizeof(void *) * NR_CPUS); memset(hv_context.vp_index, 0, sizeof(int) * NR_CPUS); memset(hv_context.event_dpc, 0, @@ -217,26 +219,18 @@ int hv_post_message(union hv_connection_ enum hv_message_type message_type, void *payload, size_t payload_size) { - struct aligned_input { - u64 alignment8; - struct hv_input_post_message msg; - }; struct hv_input_post_message *aligned_msg; u16 status; - unsigned long addr; if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) return -EMSGSIZE; - addr = (unsigned long)kmalloc(sizeof(struct aligned_input), GFP_ATOMIC); - if (!addr) - return -ENOMEM; - aligned_msg = (struct hv_input_post_message *) - (ALIGN(addr, HV_HYPERCALL_PARAM_ALIGN)); + hv_context.post_msg_page[get_cpu()]; aligned_msg->connectionid = connection_id; + aligned_msg->reserved = 0; aligned_msg->message_type = message_type; aligned_msg->payload_size = payload_size; memcpy((void *)aligned_msg->payload, payload, payload_size); @@ -244,8 +238,7 @@ int hv_post_message(union hv_connection_ status = do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL) & 0xFFFF; - kfree((void *)addr); - + put_cpu(); return status; } @@ -294,6 +287,14 @@ int hv_synic_alloc(void) pr_err("Unable to allocate SYNIC event page\n"); goto err; } + + hv_context.post_msg_page[cpu] = + (void *)get_zeroed_page(GFP_ATOMIC); + + if (hv_context.post_msg_page[cpu] == NULL) { + pr_err("Unable to allocate post msg page\n"); + goto err; + } } return 0; @@ -308,6 +309,8 @@ static void hv_synic_free_cpu(int cpu) free_page((unsigned long)hv_context.synic_event_page[cpu]); if (hv_context.synic_message_page[cpu]) free_page((unsigned long)hv_context.synic_message_page[cpu]); + if (hv_context.post_msg_page[cpu]) + free_page((unsigned long)hv_context.post_msg_page[cpu]); } void hv_synic_free(void) --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -515,6 +515,10 @@ struct hv_context { * per-cpu list of the channels based on their CPU affinity. */ struct list_head percpu_list[NR_CPUS]; + /* + * buffer to post messages to the host. + */ + void *post_msg_page[NR_CPUS]; }; extern struct hv_context hv_context; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/