soc: qcom: wcnss: simplify allocation of req

Get rid of automatic kfree and move allocation down to where it's used.

Use kzalloc_flex as we're dealing with a flexible array member.

Use struct_size to avoid some pointer math.

Add __counted_by for extra runtime analysis. Move the counting variable
assignment to right after allocation as required by __counted_by.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://lore.kernel.org/r/20260327025534.7864-1-rosenp@gmail.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

diff --git a/drivers/soc/qcom/wcnss_ctrl.c b/drivers/soc/qcom/wcnss_ctrl.c
index 62b424e90d908d1979a870e55b7e9e91ee47e5ff..ffb31a049d4a922ac197080492b8d447960682b1 100644 (file)
--- a/drivers/soc/qcom/wcnss_ctrl.c
+++ b/drivers/soc/qcom/wcnss_ctrl.c
@@ -94,7 +94,7 @@ struct wcnss_download_nv_req {
        u16 seq;
        u16 last;
        u32 frag_size;
-       u8 fragment[];
+       u8 fragment[] __counted_by(frag_size);
 } __packed;
 
 /**
@@ -201,16 +201,12 @@ static int wcnss_download_nv(struct wcnss_ctrl *wcnss, bool *expect_cbc)
 {
        const struct firmware *fw;
        struct device *dev = wcnss->dev;
+       struct wcnss_download_nv_req *req;
        const char *nvbin = NVBIN_FILE;
        const void *data;
        ssize_t left;
        int ret;
 
-       struct wcnss_download_nv_req *req __free(kfree) = kzalloc(sizeof(*req) + NV_FRAGMENT_SIZE,
-                                                                 GFP_KERNEL);
-       if (!req)
-               return -ENOMEM;
-
        ret = of_property_read_string(dev->of_node, "firmware-name", &nvbin);
        if (ret < 0 && ret != -EINVAL)
                return ret;
@@ -224,11 +220,15 @@ static int wcnss_download_nv(struct wcnss_ctrl *wcnss, bool *expect_cbc)
        data = fw->data;
        left = fw->size;
 
+       req = kzalloc_flex(*req, fragment, NV_FRAGMENT_SIZE);
+       if (!req)
+               return -ENOMEM;
+
+       req->frag_size = NV_FRAGMENT_SIZE;
        req->hdr.type = WCNSS_DOWNLOAD_NV_REQ;
-       req->hdr.len = sizeof(*req) + NV_FRAGMENT_SIZE;
+       req->hdr.len = struct_size(req, fragment, NV_FRAGMENT_SIZE);
 
        req->last = 0;
-       req->frag_size = NV_FRAGMENT_SIZE;
 
        req->seq = 0;
        do {
@@ -264,6 +264,7 @@ static int wcnss_download_nv(struct wcnss_ctrl *wcnss, bool *expect_cbc)
 
 release_fw:
        release_firmware(fw);
+       kfree(req);
 
        return ret;
 }