soc: qcom: smd: Remove use of VLAIS

Usage of VLAIS prevents clang from compiling this file, and it
also opens us to the possibility of allocating a large structure
on the stack to the point that we blow past the limit of the
kernel stack. Remove the VLAIS and allocate a structure on the
heap with kmalloc so that we're safer and more clang friendly.

Cc: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Andy Gross <agross@codeaurora.org>

1 files changed, 19 insertions, 13 deletions

diff --git a/drivers/soc/qcom/smd-rpm.c b/drivers/soc/qcom/smd-rpm.c
index 1392ccf14a20..7709579d63d0 100644
--- a/drivers/soc/qcom/smd-rpm.c
+++ b/drivers/soc/qcom/smd-rpm.c
@@ -17,6 +17,7 @@
 #include <linux/of_platform.h>
 #include <linux/io.h>
 #include <linux/interrupt.h>
+#include <linux/slab.h>
 
 #include <linux/soc/qcom/smd.h>
 #include <linux/soc/qcom/smd-rpm.h>
@@ -104,30 +105,34 @@ int qcom_rpm_smd_write(struct qcom_smd_rpm *rpm,
         static unsigned msg_id = 1;
         int left;
         int ret;
-
         struct {
                 struct qcom_rpm_header hdr;
                 struct qcom_rpm_request req;
-                u8 payload[count];
-        } pkt;
+                u8 payload[];
+        } *pkt;
+        size_t size = sizeof(*pkt) + count;
 
         /* SMD packets to the RPM may not exceed 256 bytes */
-        if (WARN_ON(sizeof(pkt) >= 256))
+        if (WARN_ON(size >= 256))
                 return -EINVAL;
 
+        pkt = kmalloc(size, GFP_KERNEL);
+        if (!pkt)
+                return -ENOMEM;
+
         mutex_lock(&rpm->lock);
 
-        pkt.hdr.service_type = RPM_SERVICE_TYPE_REQUEST;
-        pkt.hdr.length = sizeof(struct qcom_rpm_request) + count;
+        pkt->hdr.service_type = RPM_SERVICE_TYPE_REQUEST;
+        pkt->hdr.length = sizeof(struct qcom_rpm_request) + count;
 
-        pkt.req.msg_id = msg_id++;
-        pkt.req.flags = BIT(state);
-        pkt.req.type = type;
-        pkt.req.id = id;
-        pkt.req.data_len = count;
-        memcpy(pkt.payload, buf, count);
+        pkt->req.msg_id = msg_id++;
+        pkt->req.flags = BIT(state);
+        pkt->req.type = type;
+        pkt->req.id = id;
+        pkt->req.data_len = count;
+        memcpy(pkt->payload, buf, count);
 
-        ret = qcom_smd_send(rpm->rpm_channel, &pkt, sizeof(pkt));
+        ret = qcom_smd_send(rpm->rpm_channel, pkt, sizeof(*pkt));
         if (ret)
                 goto out;
 
@@ -138,6 +143,7 @@ int qcom_rpm_smd_write(struct qcom_smd_rpm *rpm,
                 ret = rpm->ack_status;
 
 out:
+        kfree(pkt);
         mutex_unlock(&rpm->lock);
         return ret;
 }