From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754207AbcCRXiS (ORCPT ); Fri, 18 Mar 2016 19:38:18 -0400 Received: from p3plsmtps2ded02.prod.phx3.secureserver.net ([208.109.80.59]:32968 "EHLO p3plsmtps2ded02.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753418AbcCRXht (ORCPT ); Fri, 18 Mar 2016 19:37:49 -0400 x-originating-ip: 72.167.245.219 From: "K. Y. Srinivasan" To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com, jasowang@redhat.c Cc: "K. Y. Srinivasan" Subject: [PATCH 5/5] Drivers: hv: vmbus: Implement copy-free read APIs Date: Fri, 18 Mar 2016 18:14:25 -0700 Message-Id: <1458350065-32666-5-git-send-email-kys@microsoft.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1458350065-32666-1-git-send-email-kys@microsoft.com> References: <1458350038-32624-1-git-send-email-kys@microsoft.com> <1458350065-32666-1-git-send-email-kys@microsoft.com> X-CMAE-Envelope: MS4wfLxMxcSAot9D0tWUOd/oWYp7kZF0nhizmZI7Do/QcwCxqs3BIBkhyzd3RHN6cQg+1oxQtqXvVFyXQ8vaQIS4cRLuNV6wnsr9xHdwtLtpB8B6p5V+LHJk dAd4QyT3EbTZbAsF8XPgCwd2ed9EKzEPaaDIhFd960/hRHiislSRJL7Tgz6TfSQEuJ1vhMX67IEGfZMMKKga4e3QMXRZjfo4nWSPlBWhBRA6OjFsTXNK2myt ahIkv+WjcpXFKQss7l4LpRUs2ApsLk6JccCbH2Br/BflQ/uGstho/0TkHHaAHZd7aBEPue9poeapEy0Q06EP1waXd39bh3wyuUhKfd06pjr0VzhdEbKOYpLr HKzsOmrDyXpAeJDu1pz73pX6xTWUPng/JBgdgogUoZxeVpV4vhN7LqymTQhjOHcFrXozzzaS Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Implement copy-free read APIs. Signed-off-by: K. Y. Srinivasan --- drivers/hv/ring_buffer.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/hyperv.h | 6 +++++ 2 files changed, 61 insertions(+), 0 deletions(-) diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index c2c2b2e..c80e1f3 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -444,3 +444,58 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, return ret; } + +/* + * In-place read functions. + */ +bool get_next_pkt_raw(struct vmbus_channel *channel, + struct vmpacket_descriptor **desc) +{ + struct hv_ring_buffer_info *ring_info = &channel->inbound; + u32 read_loc = ring_info->ring_buffer->read_index; + void *ring_buffer = hv_get_ring_buffer(ring_info); + struct vmpacket_descriptor *cur_desc; + u32 packetlen; + u32 dsize = ring_info->ring_datasize; + u32 bytes_avail_toread = hv_get_bytes_to_read(ring_info); + + if (bytes_avail_toread < sizeof(struct vmpacket_descriptor)) + return false; + + if ((read_loc + sizeof(*desc)) > dsize) + return false; + + cur_desc = ring_buffer + read_loc; + packetlen = cur_desc->len8 << 3; + + if ((read_loc + packetlen + 8) > (dsize - 1)) + return false; + + *desc = cur_desc; + return true; +} +EXPORT_SYMBOL_GPL(get_next_pkt_raw); + +void put_pkt_raw(struct vmbus_channel *channel, + struct vmpacket_descriptor *desc) +{ + struct hv_ring_buffer_info *ring_info = &channel->inbound; + u32 read_loc = ring_info->ring_buffer->read_index; + u32 packetlen = desc->len8 << 3; + u32 dsize = ring_info->ring_datasize; + + if ((read_loc + packetlen + 8) > dsize) + BUG(); + + /* + * Make sure all reads are done before we update the read index since + * the writer may start writing to the read area once the read index + * is updated. + */ + virt_mb(); + ring_info->ring_buffer->read_index += packetlen + 8; + + if (hv_need_to_signal_on_read(ring_info)) + vmbus_set_event(channel); +} +EXPORT_SYMBOL_GPL(put_pkt_raw); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index a6b053c..455f3f0 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1035,6 +1035,12 @@ extern int vmbus_recvpacket_raw(struct vmbus_channel *channel, u32 *buffer_actual_len, u64 *requestid); +bool get_next_pkt_raw(struct vmbus_channel *channel, + struct vmpacket_descriptor **desc); + +void put_pkt_raw(struct vmbus_channel *channel, + struct vmpacket_descriptor *desc); + extern void vmbus_ontimer(unsigned long data); -- 1.7.4.1