02.01.2022 17:25, Hector Martin пишет:

On 2022/01/02 16:08, Dmitry Osipenko wrote:

quoted

26.12.2021 18:35, Hector Martin пишет:

quoted

+static void brcm_free_alt_fw_paths(const char **alt_paths)
+{
+	int i;
+
+	if (!alt_paths)
+		return;
+
+	for (i = 0; alt_paths[i]; i++)
+		kfree(alt_paths[i]);
+
+	kfree(alt_paths);
 }
 
 static int brcmf_fw_request_firmware(const struct firmware **fw,
 				     struct brcmf_fw *fwctx)
 {
 	struct brcmf_fw_item *cur = &fwctx->req->items[fwctx->curpos];
-	int ret;
+	int ret, i;
 
 	/* Files can be board-specific, first try a board-specific path */
 	if (cur->type == BRCMF_FW_TYPE_NVRAM && fwctx->req->board_type) {
-		char *alt_path;
+		const char **alt_paths = brcm_alt_fw_paths(cur->path, fwctx);
 
-		alt_path = brcm_alt_fw_path(cur->path, fwctx->req->board_type);
-		if (!alt_path)
+		if (!alt_paths)
 			goto fallback;
 
-		ret = request_firmware(fw, alt_path, fwctx->dev);
-		kfree(alt_path);
-		if (ret == 0)
-			return ret;
+		for (i = 0; alt_paths[i]; i++) {
+			ret = firmware_request_nowarn(fw, alt_paths[i], fwctx->dev);
+			if (ret == 0) {
+				brcm_free_alt_fw_paths(alt_paths);
+				return ret;
+			}
+		}
+		brcm_free_alt_fw_paths(alt_paths);
 	}
 
 fallback:

@@ -641,6 +663,9 @@ static void brcmf_fw_request_done(const struct firmware *fw, void *ctx)
 	struct brcmf_fw *fwctx = ctx;
 	int ret;
 
+	brcm_free_alt_fw_paths(fwctx->alt_paths);
+	fwctx->alt_paths = NULL;

It looks suspicious that fwctx->alt_paths isn't zero'ed by other code
paths. The brcm_free_alt_fw_paths() should take fwctx for the argument
and fwctx->alt_paths should be set to NULL there.

There are multiple code paths for alt_paths; the initial firmware lookup
uses fwctx->alt_paths, and once we know the firmware load succeeded we
use blocking firmware requests for NVRAM/CLM/etc and those do not use
the fwctx member, but rather just keep alt_paths in function scope
(brcmf_fw_request_firmware). You're right that there was a rebase SNAFU
there though, I'll compile test each patch before sending v2. Sorry
about that. In this series the code should build again by patch #6.

Are you thinking of any particular code paths? As far as I saw when
writing this, brcmf_fw_request_done() should always get called whether
things succeed or fail. There are no other code paths that free
fwctx->alt_paths.

It should be okay in the particular case then. But this is not obvious
without taking a closer look at the code, which is a sign that there is
some room for improvement.

quoted

On the other hand, I'd change the **alt_paths to a fixed-size array.
This should simplify the code, making it easier to follow and maintain.

-	const char **alt_paths;
+	char *alt_paths[BRCM_MAX_ALT_FW_PATHS];

Then you also won't need to NULL-terminate the array, which is a common
source of bugs in kernel.

That sounds reasonable, it'll certainly make the code simpler. I'll do
that for v2.

Feel free to CC me on v2. I'll take a closer look and give a test to the
patches on older hardware, checking for regressions.