lkml.org 
[lkml]   [2017]   [Dec]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH 18/60] hyper_dmabuf: reset comm channel when one end has disconnected.
Date
From: Mateusz Polrola <mateuszx.potrola@intel.com>

When exporter or importer is disconnected, ring buffer should be
reinitialzed, otherwise on next reconnection exporter/importer will
receive old requests/responses remaining in the ring buffer, which are
not valid anymore.

This patch also blocks back ring irq until communication channel is
initialized and fully active to prevent a race condition.

Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
---
.../xen/hyper_dmabuf/xen/hyper_dmabuf_xen_comm.c | 24 +++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_comm.c b/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_comm.c
index 5e7a250..b629032 100644
--- a/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_comm.c
+++ b/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_comm.c
@@ -282,6 +282,7 @@ int hyper_dmabuf_xen_init_tx_rbuf(int domid)
void hyper_dmabuf_xen_cleanup_tx_rbuf(int domid)
{
struct xen_comm_tx_ring_info *ring_info;
+ struct xen_comm_rx_ring_info *rx_ring_info;

/* check if we at all have exporter ring for given rdomain */
ring_info = xen_comm_find_tx_ring(domid);
@@ -307,6 +308,12 @@ void hyper_dmabuf_xen_cleanup_tx_rbuf(int domid)
(unsigned long) ring_info->ring_front.sring);

kfree(ring_info);
+
+ rx_ring_info = xen_comm_find_rx_ring(domid);
+ if (!rx_ring_info)
+ return;
+
+ BACK_RING_INIT(&(rx_ring_info->ring_back), rx_ring_info->ring_back.sring, PAGE_SIZE);
}

/* importer needs to know about shared page and port numbers for
@@ -378,9 +385,8 @@ int hyper_dmabuf_xen_init_rx_rbuf(int domid)

BACK_RING_INIT(&ring_info->ring_back, sring, PAGE_SIZE);

- ret = bind_interdomain_evtchn_to_irqhandler(domid, rx_port,
- back_ring_isr, 0,
- NULL, (void*)ring_info);
+ ret = bind_interdomain_evtchn_to_irq(domid, rx_port);
+
if (ret < 0) {
return -EINVAL;
}
@@ -399,6 +405,10 @@ int hyper_dmabuf_xen_init_rx_rbuf(int domid)
ret = hyper_dmabuf_xen_init_tx_rbuf(domid);
}

+ ret = request_irq(ring_info->irq,
+ back_ring_isr, 0,
+ NULL, (void*)ring_info);
+
return ret;
}

@@ -406,6 +416,7 @@ int hyper_dmabuf_xen_init_rx_rbuf(int domid)
void hyper_dmabuf_xen_cleanup_rx_rbuf(int domid)
{
struct xen_comm_rx_ring_info *ring_info;
+ struct xen_comm_tx_ring_info *tx_ring_info;
struct page *shared_ring;

/* check if we have importer ring created for given sdomain */
@@ -425,6 +436,13 @@ void hyper_dmabuf_xen_cleanup_rx_rbuf(int domid)
gnttab_free_pages(1, &shared_ring);

kfree(ring_info);
+
+ tx_ring_info = xen_comm_find_tx_ring(domid);
+ if (!tx_ring_info)
+ return;
+
+ SHARED_RING_INIT(tx_ring_info->ring_front.sring);
+ FRONT_RING_INIT(&(tx_ring_info->ring_front), tx_ring_info->ring_front.sring, PAGE_SIZE);
}

int hyper_dmabuf_xen_init_comm_env(void)
--
2.7.4
\
 
 \ /
  Last update: 2017-12-19 20:50    [W:0.336 / U:0.324 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site