From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424294AbcFMTIM (ORCPT ); Mon, 13 Jun 2016 15:08:12 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43577 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933538AbcFMSh3 (ORCPT ); Mon, 13 Jun 2016 14:37:29 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Greg Kroah-Hartman" , "K. Y. Srinivasan" , "Christopher Oo" Date: Mon, 13 Jun 2016 19:36:37 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 064/114] Drivers: hv_vmbus: Fix signal to host condition In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.36-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Christopher Oo commit a5cca686ce0ef4909deaee4ed46dd991e3a9ece4 upstream. Fixes a bug where previously hv_ringbuffer_read would pass in the old number of bytes available to read instead of the expected old read index when calculating when to signal to the host that the ringbuffer is empty. Since the previous write size is already saved, also changes the hv_need_to_signal_on_read to use the previously read value rather than recalculating it. Signed-off-by: Christopher Oo Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- drivers/hv/ring_buffer.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-) --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -103,10 +103,9 @@ static bool hv_need_to_signal(u32 old_wr * there is room for the producer to send the pending packet. */ -static bool hv_need_to_signal_on_read(u32 old_rd, - struct hv_ring_buffer_info *rbi) +static bool hv_need_to_signal_on_read(u32 prev_write_sz, + struct hv_ring_buffer_info *rbi) { - u32 prev_write_sz; u32 cur_write_sz; u32 r_size; u32 write_loc = rbi->ring_buffer->write_index; @@ -123,10 +122,6 @@ static bool hv_need_to_signal_on_read(u3 cur_write_sz = write_loc >= read_loc ? r_size - (write_loc - read_loc) : read_loc - write_loc; - prev_write_sz = write_loc >= old_rd ? r_size - (write_loc - old_rd) : - old_rd - write_loc; - - if ((prev_write_sz < pending_sz) && (cur_write_sz >= pending_sz)) return true; @@ -512,7 +507,6 @@ int hv_ringbuffer_read(struct hv_ring_bu u32 next_read_location = 0; u64 prev_indices = 0; unsigned long flags; - u32 old_read; if (buflen <= 0) return -EINVAL; @@ -523,8 +517,6 @@ int hv_ringbuffer_read(struct hv_ring_bu &bytes_avail_toread, &bytes_avail_towrite); - old_read = bytes_avail_toread; - /* Make sure there is something to read */ if (bytes_avail_toread < buflen) { spin_unlock_irqrestore(&inring_info->ring_lock, flags); @@ -555,7 +547,7 @@ int hv_ringbuffer_read(struct hv_ring_bu spin_unlock_irqrestore(&inring_info->ring_lock, flags); - *signal = hv_need_to_signal_on_read(old_read, inring_info); + *signal = hv_need_to_signal_on_read(bytes_avail_towrite, inring_info); return 0; }