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authorMichael Kelley <mikelley@microsoft.com>2022-02-09 19:11:10 +0300
committerWei Liu <wei.liu@kernel.org>2022-02-18 16:08:18 +0300
commit6de74d1069b821e96460d0fc2edfc35785db04fb (patch)
tree7670a968e8a04d89202a732790a580e2a7f41a8c /drivers/hv
parent4ee524587105011ef43e5bd3ef5ed019715363dd (diff)
downloadlinux-6de74d1069b821e96460d0fc2edfc35785db04fb.tar.xz
hv_utils: Add comment about max VMbus packet size in VSS driver
The VSS driver allocates a VMbus receive buffer significantly larger than sizeof(hv_vss_msg), with no explanation. To help prevent future mistakes, add a #define and comment about why this is done. No functional change. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1644423070-75125-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/hv_snapshot.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index 6018b9d1b1fb..0d2184be1691 100644
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -31,6 +31,9 @@ static const int fw_versions[] = {
UTIL_FW_VERSION
};
+/* See comment with struct hv_vss_msg regarding the max VMbus packet size */
+#define VSS_MAX_PKT_SIZE (HV_HYP_PAGE_SIZE * 2)
+
/*
* Timeout values are based on expecations from host
*/
@@ -298,7 +301,7 @@ void hv_vss_onchannelcallback(void *context)
if (vss_transaction.state > HVUTIL_READY)
return;
- if (vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 2, &recvlen, &requestid)) {
+ if (vmbus_recvpacket(channel, recv_buffer, VSS_MAX_PKT_SIZE, &recvlen, &requestid)) {
pr_err_ratelimited("VSS request received. Could not read into recv buf\n");
return;
}
@@ -375,7 +378,7 @@ hv_vss_init(struct hv_util_service *srv)
}
recv_buffer = srv->recv_buffer;
vss_transaction.recv_channel = srv->channel;
- vss_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
+ vss_transaction.recv_channel->max_pkt_size = VSS_MAX_PKT_SIZE;
/*
* When this driver loads, the user level daemon that