From: "Andrea Parri (Microsoft)" <parri.andrea@gmail.com>
To: linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org
Cc: "K . Y . Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>,
Michael Kelley <mikelley@microsoft.com>,
Juan Vazquez <juvazq@microsoft.com>,
Saruhan Karademir <skarade@microsoft.com>,
"Andrea Parri (Microsoft)" <parri.andrea@gmail.com>
Subject: [PATCH v3 2/6] Drivers: hv: vmbus: Reduce number of references to message in vmbus_on_msg_dpc()
Date: Wed, 9 Dec 2020 08:08:23 +0100 [thread overview]
Message-ID: <20201209070827.29335-3-parri.andrea@gmail.com> (raw)
In-Reply-To: <20201209070827.29335-1-parri.andrea@gmail.com>
Simplify the function by removing various references to the hv_message
'msg', introduce local variables 'msgtype' and 'payload_size'.
Suggested-by: Juan Vazquez <juvazq@microsoft.com>
Suggested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
---
Changes since v2:
- Squash patches #2 and #3
- Revisit commit message
drivers/hv/vmbus_drv.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 502f8cd95f6d4..44bcf9ccdaf5f 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1057,9 +1057,11 @@ void vmbus_on_msg_dpc(unsigned long data)
struct hv_message *msg = (struct hv_message *)page_addr +
VMBUS_MESSAGE_SINT;
struct vmbus_channel_message_header *hdr;
+ enum vmbus_channel_message_type msgtype;
const struct vmbus_channel_message_table_entry *entry;
struct onmessage_work_context *ctx;
u32 message_type = msg->header.message_type;
+ __u8 payload_size;
/*
* 'enum vmbus_channel_message_type' is supposed to always be 'u32' as
@@ -1073,40 +1075,38 @@ void vmbus_on_msg_dpc(unsigned long data)
return;
hdr = (struct vmbus_channel_message_header *)msg->u.payload;
+ msgtype = hdr->msgtype;
trace_vmbus_on_msg_dpc(hdr);
- if (hdr->msgtype >= CHANNELMSG_COUNT) {
- WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
+ if (msgtype >= CHANNELMSG_COUNT) {
+ WARN_ONCE(1, "unknown msgtype=%d\n", msgtype);
goto msg_handled;
}
- if (msg->header.payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) {
- WARN_ONCE(1, "payload size is too large (%d)\n",
- msg->header.payload_size);
+ payload_size = msg->header.payload_size;
+ if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) {
+ WARN_ONCE(1, "payload size is too large (%d)\n", payload_size);
goto msg_handled;
}
- entry = &channel_message_table[hdr->msgtype];
+ entry = &channel_message_table[msgtype];
if (!entry->message_handler)
goto msg_handled;
- if (msg->header.payload_size < entry->min_payload_len) {
- WARN_ONCE(1, "message too short: msgtype=%d len=%d\n",
- hdr->msgtype, msg->header.payload_size);
+ if (payload_size < entry->min_payload_len) {
+ WARN_ONCE(1, "message too short: msgtype=%d len=%d\n", msgtype, payload_size);
goto msg_handled;
}
if (entry->handler_type == VMHT_BLOCKING) {
- ctx = kmalloc(sizeof(*ctx) + msg->header.payload_size,
- GFP_ATOMIC);
+ ctx = kmalloc(sizeof(*ctx) + payload_size, GFP_ATOMIC);
if (ctx == NULL)
return;
INIT_WORK(&ctx->work, vmbus_onmessage_work);
- memcpy(&ctx->msg, msg, sizeof(msg->header) +
- msg->header.payload_size);
+ memcpy(&ctx->msg, msg, sizeof(msg->header) + payload_size);
/*
* The host can generate a rescind message while we
@@ -1115,7 +1115,7 @@ void vmbus_on_msg_dpc(unsigned long data)
* by offer_in_progress and by channel_mutex. See also the
* inline comments in vmbus_onoffer_rescind().
*/
- switch (hdr->msgtype) {
+ switch (msgtype) {
case CHANNELMSG_RESCIND_CHANNELOFFER:
/*
* If we are handling the rescind message;
--
2.25.1
next prev parent reply other threads:[~2020-12-09 7:10 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 7:08 [PATCH v3 0/6] Drivers: hv: vmbus: More VMBus-hardening changes Andrea Parri (Microsoft)
2020-12-09 7:08 ` [PATCH v3 1/6] Drivers: hv: vmbus: Initialize memory to be sent to the host Andrea Parri (Microsoft)
2020-12-09 7:08 ` Andrea Parri (Microsoft) [this message]
2020-12-09 18:26 ` [PATCH v3 2/6] Drivers: hv: vmbus: Reduce number of references to message in vmbus_on_msg_dpc() Michael Kelley
2020-12-09 7:08 ` [PATCH v3 3/6] Drivers: hv: vmbus: Copy the hv_message " Andrea Parri (Microsoft)
2020-12-09 18:26 ` Michael Kelley
2020-12-09 7:08 ` [PATCH v3 4/6] Drivers: hv: vmbus: Avoid use-after-free in vmbus_onoffer_rescind() Andrea Parri (Microsoft)
2020-12-09 7:08 ` [PATCH v3 5/6] Drivers: hv: vmbus: Resolve race condition " Andrea Parri (Microsoft)
2020-12-15 4:45 ` Michael Kelley
2020-12-09 7:08 ` [PATCH v3 6/6] Drivers: hv: vmbus: Do not allow overwriting vmbus_connection.channels[] Andrea Parri (Microsoft)
2021-01-05 12:49 ` [PATCH v3 0/6] Drivers: hv: vmbus: More VMBus-hardening changes Wei Liu
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