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authorJake Oshins <jakeo@microsoft.com>2016-08-30 00:35:06 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-09-15 08:27:50 +0200
commit45a063156fc5822f3f72bee0bc986de63e7ed73b (patch)
tree164e68c0864199f311a9236ac3a8d796739fd97d
parentd4009e4b6e309e222c5245056f4d6e1a4da88026 (diff)
downloadlinux-linaro-stable-45a063156fc5822f3f72bee0bc986de63e7ed73b.tar.gz
drivers:hv: Lock access to hyperv_mmio resource tree
[ Upstream commit e16dad6bfe1437aaee565f875a6713ca7ce81bdf ] In existing code, this tree of resources is created in single-threaded code and never modified after it is created, and thus needs no locking. This patch introduces a semaphore for tree access, as other patches in this series introduce run-time modifications of this resource tree which can happen on multiple threads. Signed-off-by: Jake Oshins <jakeo@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
-rw-r--r--drivers/hv/vmbus_drv.c16
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 55952d1ed336..509ed9731630 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -105,6 +105,7 @@ static struct notifier_block hyperv_panic_block = {
};
struct resource *hyperv_mmio;
+DEFINE_SEMAPHORE(hyperv_mmio_lock);
static int vmbus_exists(void)
{
@@ -1140,7 +1141,10 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
resource_size_t range_min, range_max, start, local_min, local_max;
const char *dev_n = dev_name(&device_obj->device);
u32 fb_end = screen_info.lfb_base + (screen_info.lfb_size << 1);
- int i;
+ int i, retval;
+
+ retval = -ENXIO;
+ down(&hyperv_mmio_lock);
for (iter = hyperv_mmio; iter; iter = iter->sibling) {
if ((iter->start >= max) || (iter->end <= min))
@@ -1177,13 +1181,17 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
for (; start + size - 1 <= local_max; start += align) {
*new = request_mem_region_exclusive(start, size,
dev_n);
- if (*new)
- return 0;
+ if (*new) {
+ retval = 0;
+ goto exit;
+ }
}
}
}
- return -ENXIO;
+exit:
+ up(&hyperv_mmio_lock);
+ return retval;
}
EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);