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Diffstat (limited to 'drivers/hv/channel.c')
-rw-r--r--drivers/hv/channel.c138
1 files changed, 66 insertions, 72 deletions
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index c4dcab048cb8..1161d68a1863 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -28,6 +28,7 @@
#include <linux/module.h>
#include <linux/hyperv.h>
#include <linux/uio.h>
+#include <linux/interrupt.h>
#include "hyperv_vmbus.h"
@@ -496,8 +497,33 @@ static void reset_channel_cb(void *arg)
static int vmbus_close_internal(struct vmbus_channel *channel)
{
struct vmbus_channel_close_channel *msg;
+ struct tasklet_struct *tasklet;
int ret;
+ /*
+ * process_chn_event(), running in the tasklet, can race
+ * with vmbus_close_internal() in the case of SMP guest, e.g., when
+ * the former is accessing channel->inbound.ring_buffer, the latter
+ * could be freeing the ring_buffer pages.
+ *
+ * To resolve the race, we can serialize them by disabling the
+ * tasklet when the latter is running here.
+ */
+ tasklet = hv_context.event_dpc[channel->target_cpu];
+ tasklet_disable(tasklet);
+
+ /*
+ * In case a device driver's probe() fails (e.g.,
+ * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
+ * rescinded later (e.g., we dynamically disble an Integrated Service
+ * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
+ * here we should skip most of the below cleanup work.
+ */
+ if (channel->state != CHANNEL_OPENED_STATE) {
+ ret = -EINVAL;
+ goto out;
+ }
+
channel->state = CHANNEL_OPEN_STATE;
channel->sc_creation_callback = NULL;
/* Stop callback and cancel the timer asap */
@@ -525,7 +551,7 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
* If we failed to post the close msg,
* it is perhaps better to leak memory.
*/
- return ret;
+ goto out;
}
/* Tear down the gpadl for the channel's ring buffer */
@@ -538,7 +564,7 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
* If we failed to teardown gpadl,
* it is perhaps better to leak memory.
*/
- return ret;
+ goto out;
}
}
@@ -549,12 +575,9 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
free_pages((unsigned long)channel->ringbuffer_pages,
get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
- /*
- * If the channel has been rescinded; process device removal.
- */
- if (channel->rescind)
- hv_process_channel_removal(channel,
- channel->offermsg.child_relid);
+out:
+ tasklet_enable(tasklet);
+
return ret;
}
@@ -630,10 +653,19 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
* on the ring. We will not signal if more data is
* to be placed.
*
+ * Based on the channel signal state, we will decide
+ * which signaling policy will be applied.
+ *
* If we cannot write to the ring-buffer; signal the host
* even if we may not have written anything. This is a rare
* enough condition that it should not matter.
*/
+
+ if (channel->signal_policy)
+ signal = true;
+ else
+ kick_q = true;
+
if (((ret == 0) && kick_q && signal) || (ret))
vmbus_setevent(channel);
@@ -733,10 +765,19 @@ int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
* on the ring. We will not signal if more data is
* to be placed.
*
+ * Based on the channel signal state, we will decide
+ * which signaling policy will be applied.
+ *
* If we cannot write to the ring-buffer; signal the host
* even if we may not have written anything. This is a rare
* enough condition that it should not matter.
*/
+
+ if (channel->signal_policy)
+ signal = true;
+ else
+ kick_q = true;
+
if (((ret == 0) && kick_q && signal) || (ret))
vmbus_setevent(channel);
@@ -881,46 +922,29 @@ EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
*
* Mainly used by Hyper-V drivers.
*/
-int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
- u32 bufferlen, u32 *buffer_actual_len, u64 *requestid)
+static inline int
+__vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
+ u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
+ bool raw)
{
- struct vmpacket_descriptor desc;
- u32 packetlen;
- u32 userlen;
int ret;
bool signal = false;
- *buffer_actual_len = 0;
- *requestid = 0;
-
-
- ret = hv_ringbuffer_peek(&channel->inbound, &desc,
- sizeof(struct vmpacket_descriptor));
- if (ret != 0)
- return 0;
-
- packetlen = desc.len8 << 3;
- userlen = packetlen - (desc.offset8 << 3);
-
- *buffer_actual_len = userlen;
-
- if (userlen > bufferlen) {
-
- pr_err("Buffer too small - got %d needs %d\n",
- bufferlen, userlen);
- return -ETOOSMALL;
- }
-
- *requestid = desc.trans_id;
-
- /* Copy over the packet to the user buffer */
- ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
- (desc.offset8 << 3), &signal);
+ ret = hv_ringbuffer_read(&channel->inbound, buffer, bufferlen,
+ buffer_actual_len, requestid, &signal, raw);
if (signal)
vmbus_setevent(channel);
- return 0;
+ return ret;
+}
+
+int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
+ u32 bufferlen, u32 *buffer_actual_len,
+ u64 *requestid)
+{
+ return __vmbus_recvpacket(channel, buffer, bufferlen,
+ buffer_actual_len, requestid, false);
}
EXPORT_SYMBOL(vmbus_recvpacket);
@@ -931,37 +955,7 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
u32 bufferlen, u32 *buffer_actual_len,
u64 *requestid)
{
- struct vmpacket_descriptor desc;
- u32 packetlen;
- int ret;
- bool signal = false;
-
- *buffer_actual_len = 0;
- *requestid = 0;
-
-
- ret = hv_ringbuffer_peek(&channel->inbound, &desc,
- sizeof(struct vmpacket_descriptor));
- if (ret != 0)
- return 0;
-
-
- packetlen = desc.len8 << 3;
-
- *buffer_actual_len = packetlen;
-
- if (packetlen > bufferlen)
- return -ENOBUFS;
-
- *requestid = desc.trans_id;
-
- /* Copy over the entire packet to the user buffer */
- ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0,
- &signal);
-
- if (signal)
- vmbus_setevent(channel);
-
- return ret;
+ return __vmbus_recvpacket(channel, buffer, bufferlen,
+ buffer_actual_len, requestid, true);
}
EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);