[PATCH 0/3] Drivers: hv: vmbus: Miscellaneous fixes

[PATCH 0/3] Drivers: hv: vmbus: Miscellaneous fixes

[kys]

From: "K. Y. Srinivasan" <kys@microsoft.com>

Miscellaneous fixes.

Dexuan Cui (1):
  Drivers: hv: vmbus: Reset the channel callback in
    vmbus_onoffer_rescind()

Michael Kelley (2):
  Drivers: hv: vmbus: Remove use of slow_virt_to_phys()
  Drivers: hv: vmbus: Cleanup synic memory free path

 drivers/hv/channel.c      | 67 +++++++++++++++++++++++++--------------
 drivers/hv/channel_mgmt.c |  6 ++++
 drivers/hv/hv.c           | 14 ++++----
 include/linux/hyperv.h    |  2 ++
 4 files changed, 60 insertions(+), 29 deletions(-)

-- 
2.17.1

[PATCH 1/3] Drivers: hv: vmbus: Reset the channel callback in vmbus_onoffer_rescind()

[kys]

From: Dexuan Cui <decui@microsoft.com>

Before setting channel->rescind in vmbus_rescind_cleanup(), we should make
sure the channel callback won't run any more, otherwise a high-level
driver like pci_hyperv, which may be infinitely waiting for the host VSP's
response and notices the channel has been rescinded, can't safely give
up: e.g., in hv_pci_protocol_negotiation() -> wait_for_response(), it's
unsafe to exit from wait_for_response() and proceed with the on-stack
variable "comp_pkt" popped. The issue was originally spotted by
Michael Kelley <mikelley@microsoft.com>.

In vmbus_close_internal(), the patch also minimizes the range protected by
disabling/enabling channel->callback_event: we don't really need that for
the whole function.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Cc: stable@vger.kernel.org
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/channel.c      | 40 +++++++++++++++++++++++----------------
 drivers/hv/channel_mgmt.c |  6 ++++++
 include/linux/hyperv.h    |  2 ++
 3 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index ba0a092ae085..c3949220b770 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -558,11 +558,8 @@ static void reset_channel_cb(void *arg)
 	channel->onchannel_callback = NULL;
 }
 
-static int vmbus_close_internal(struct vmbus_channel *channel)
+void vmbus_reset_channel_cb(struct vmbus_channel *channel)
 {
-	struct vmbus_channel_close_channel *msg;
-	int ret;
-
 	/*
 	 * vmbus_on_event(), running in the per-channel tasklet, can race
 	 * with vmbus_close_internal() in the case of SMP guest, e.g., when
@@ -572,6 +569,29 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
 	 */
 	tasklet_disable(&channel->callback_event);
 
+	channel->sc_creation_callback = NULL;
+
+	/* Stop the callback asap */
+	if (channel->target_cpu != get_cpu()) {
+		put_cpu();
+		smp_call_function_single(channel->target_cpu, reset_channel_cb,
+					 channel, true);
+	} else {
+		reset_channel_cb(channel);
+		put_cpu();
+	}
+
+	/* Re-enable tasklet for use on re-open */
+	tasklet_enable(&channel->callback_event);
+}
+
+static int vmbus_close_internal(struct vmbus_channel *channel)
+{
+	struct vmbus_channel_close_channel *msg;
+	int ret;
+
+	vmbus_reset_channel_cb(channel);
+
 	/*
 	 * In case a device driver's probe() fails (e.g.,
 	 * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
@@ -585,16 +605,6 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
 	}
 
 	channel->state = CHANNEL_OPEN_STATE;
-	channel->sc_creation_callback = NULL;
-	/* Stop callback and cancel the timer asap */
-	if (channel->target_cpu != get_cpu()) {
-		put_cpu();
-		smp_call_function_single(channel->target_cpu, reset_channel_cb,
-					 channel, true);
-	} else {
-		reset_channel_cb(channel);
-		put_cpu();
-	}
 
 	/* Send a closing message */
 
@@ -639,8 +649,6 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
 		get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
 
 out:
-	/* re-enable tasklet for use on re-open */
-	tasklet_enable(&channel->callback_event);
 	return ret;
 }
 
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index f3b551a50653..0f0e091c117c 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -892,6 +892,12 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 		return;
 	}
 
+	/*
+	 * Before setting channel->rescind in vmbus_rescind_cleanup(), we
+	 * should make sure the channel callback is not running any more.
+	 */
+	vmbus_reset_channel_cb(channel);
+
 	/*
 	 * Now wait for offer handling to complete.
 	 */
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 2330f08062c7..efda23cf32c7 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1061,6 +1061,8 @@ extern int vmbus_establish_gpadl(struct vmbus_channel *channel,
 extern int vmbus_teardown_gpadl(struct vmbus_channel *channel,
 				     u32 gpadl_handle);
 
+void vmbus_reset_channel_cb(struct vmbus_channel *channel);
+
 extern int vmbus_recvpacket(struct vmbus_channel *channel,
 				  void *buffer,
 				  u32 bufferlen,
-- 
2.17.1

[PATCH 2/3] Drivers: hv: vmbus: Remove use of slow_virt_to_phys()

[kys]

From: Michael Kelley <mikelley@microsoft.com>

slow_virt_to_phys() is only implemented for arch/x86.
Remove its use in arch independent Hyper-V drivers, and
replace with test for vmalloc() address followed by
appropriate v-to-p function. This follows the typical
pattern of other drivers and avoids the need to implement
slow_virt_to_phys() for Hyper-V on ARM64.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/channel.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index c3949220b770..741857d80da1 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -29,12 +29,26 @@
 #include <linux/hyperv.h>
 #include <linux/uio.h>
 #include <linux/interrupt.h>
+#include <asm/page.h>
 
 #include "hyperv_vmbus.h"
 
 #define NUM_PAGES_SPANNED(addr, len) \
 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
 
+static unsigned long virt_to_hvpfn(void *addr)
+{
+	unsigned long paddr;
+
+	if (is_vmalloc_addr(addr))
+		paddr = page_to_phys(vmalloc_to_page(addr)) +
+					 offset_in_page(addr);
+	else
+		paddr = __pa(addr);
+
+	return  paddr >> PAGE_SHIFT;
+}
+
 /*
  * vmbus_setevent- Trigger an event notification on the specified
  * channel.
@@ -298,8 +312,8 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 		gpadl_header->range[0].byte_offset = 0;
 		gpadl_header->range[0].byte_count = size;
 		for (i = 0; i < pfncount; i++)
-			gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
-				kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
+			gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
+				kbuffer + PAGE_SIZE * i);
 		*msginfo = msgheader;
 
 		pfnsum = pfncount;
@@ -350,9 +364,8 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 			 * so the hypervisor guarantees that this is ok.
 			 */
 			for (i = 0; i < pfncurr; i++)
-				gpadl_body->pfn[i] = slow_virt_to_phys(
-					kbuffer + PAGE_SIZE * (pfnsum + i)) >>
-					PAGE_SHIFT;
+				gpadl_body->pfn[i] = virt_to_hvpfn(
+					kbuffer + PAGE_SIZE * (pfnsum + i));
 
 			/* add to msg header */
 			list_add_tail(&msgbody->msglistentry,
@@ -380,8 +393,8 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 		gpadl_header->range[0].byte_offset = 0;
 		gpadl_header->range[0].byte_count = size;
 		for (i = 0; i < pagecount; i++)
-			gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
-				kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
+			gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
+				kbuffer + PAGE_SIZE * i);
 
 		*msginfo = msgheader;
 	}
-- 
2.17.1

[PATCH 3/3] Drivers: hv: vmbus: Cleanup synic memory free path

[kys]

From: Michael Kelley <mikelley@microsoft.com>

clk_evt memory is not being freed when the synic is shutdown
or when there is an allocation error.  Add the appropriate
kfree() call, along with a comment to clarify how the memory
gets freed after an allocation error.  Make the free path
consistent by removing checks for NULL since kfree() and
free_page() already do the check.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/hv.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 312fe5ed7c40..748a1c4172a6 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -242,6 +242,10 @@ int hv_synic_alloc(void)
 
 	return 0;
 err:
+	/*
+	 * Any memory allocations that succeeded will be freed when
+	 * the caller cleans up by calling hv_synic_free()
+	 */
 	return -ENOMEM;
 }
 
@@ -254,12 +258,10 @@ void hv_synic_free(void)
 		struct hv_per_cpu_context *hv_cpu
 			= per_cpu_ptr(hv_context.cpu_context, cpu);
 
-		if (hv_cpu->synic_event_page)
-			free_page((unsigned long)hv_cpu->synic_event_page);
-		if (hv_cpu->synic_message_page)
-			free_page((unsigned long)hv_cpu->synic_message_page);
-		if (hv_cpu->post_msg_page)
-			free_page((unsigned long)hv_cpu->post_msg_page);
+		kfree(hv_cpu->clk_evt);
+		free_page((unsigned long)hv_cpu->synic_event_page);
+		free_page((unsigned long)hv_cpu->synic_message_page);
+		free_page((unsigned long)hv_cpu->post_msg_page);
 	}
 
 	kfree(hv_context.hv_numa_map);
-- 
2.17.1