This is a note to let you know that I've just added the patch titled Drivers: hv: vmbus: On the read path cleanup the logic to interrupt the host to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drivers-hv-vmbus-on-the-read-path-cleanup-the-logic-to-interrupt-the-host.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 3372592a140db69fd63837e81f048ab4abf8111e Mon Sep 17 00:00:00 2001 From: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> Date: Sun, 6 Nov 2016 13:14:18 -0800 Subject: Drivers: hv: vmbus: On the read path cleanup the logic to interrupt the host From: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> commit 3372592a140db69fd63837e81f048ab4abf8111e upstream. Signal the host when we determine the host is to be signaled - on th read path. The currrent code determines the need to signal in the ringbuffer code and actually issues the signal elsewhere. This can result in the host viewing this interrupt as spurious since the host may also poll the channel. Make the necessary adjustments. Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> Cc: Rolf Neugebauer <rolf.neugebauer@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/hv/channel.c | 11 ++--------- drivers/hv/hyperv_vmbus.h | 4 ++-- drivers/hv/ring_buffer.c | 7 ++++--- include/linux/hyperv.h | 12 ++++++------ 4 files changed, 14 insertions(+), 20 deletions(-) --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -879,16 +879,9 @@ __vmbus_recvpacket(struct vmbus_channel u32 bufferlen, u32 *buffer_actual_len, u64 *requestid, bool raw) { - int ret; - bool signal = false; + return hv_ringbuffer_read(channel, buffer, bufferlen, + buffer_actual_len, requestid, raw); - ret = hv_ringbuffer_read(&channel->inbound, buffer, bufferlen, - buffer_actual_len, requestid, &signal, raw); - - if (signal) - vmbus_setevent(channel); - - return ret; } int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer, --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -532,9 +532,9 @@ int hv_ringbuffer_write(struct vmbus_cha u32 kv_count, bool lock, bool kick_q); -int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, +int hv_ringbuffer_read(struct vmbus_channel *channel, void *buffer, u32 buflen, u32 *buffer_actual_len, - u64 *requestid, bool *signal, bool raw); + u64 *requestid, bool raw); void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info, struct hv_ring_buffer_debug_info *debug_info); --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -353,9 +353,9 @@ int hv_ringbuffer_write(struct vmbus_cha return 0; } -int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, +int hv_ringbuffer_read(struct vmbus_channel *channel, void *buffer, u32 buflen, u32 *buffer_actual_len, - u64 *requestid, bool *signal, bool raw) + u64 *requestid, bool raw) { u32 bytes_avail_toread; u32 next_read_location = 0; @@ -364,6 +364,7 @@ int hv_ringbuffer_read(struct hv_ring_bu u32 offset; u32 packetlen; int ret = 0; + struct hv_ring_buffer_info *inring_info = &channel->inbound; if (buflen <= 0) return -EINVAL; @@ -421,7 +422,7 @@ int hv_ringbuffer_read(struct hv_ring_bu /* Update the read index */ hv_set_next_read_location(inring_info, next_read_location); - *signal = hv_need_to_signal_on_read(inring_info); + hv_signal_on_read(channel); return ret; } --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1480,10 +1480,11 @@ hv_get_ring_buffer(struct hv_ring_buffer * there is room for the producer to send the pending packet. */ -static inline bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi) +static inline void hv_signal_on_read(struct vmbus_channel *channel) { u32 cur_write_sz; u32 pending_sz; + struct hv_ring_buffer_info *rbi = &channel->inbound; /* * Issue a full memory barrier before making the signaling decision. @@ -1501,14 +1502,14 @@ static inline bool hv_need_to_signal_on pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz); /* If the other end is not blocked on write don't bother. */ if (pending_sz == 0) - return false; + return; cur_write_sz = hv_get_bytes_to_write(rbi); if (cur_write_sz >= pending_sz) - return true; + vmbus_setevent(channel); - return false; + return; } /* @@ -1590,8 +1591,7 @@ static inline void commit_rd_index(struc virt_rmb(); ring_info->ring_buffer->read_index = ring_info->priv_read_index; - if (hv_need_to_signal_on_read(ring_info)) - vmbus_set_event(channel); + hv_signal_on_read(channel); } Patches currently in stable-queue which might be from kys@xxxxxxxxxxxxx are queue-4.9/drivers-hv-vmbus-on-the-read-path-cleanup-the-logic-to-interrupt-the-host.patch queue-4.9/drivers-hv-vmbus-finally-fix-hv_need_to_signal_on_read.patch queue-4.9/drivers-hv-vmbus-base-host-signaling-strictly-on-the-ring-state.patch queue-4.9/drivers-hv-vmbus-on-write-cleanup-the-logic-to-interrupt-the-host.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html