netdev - [PATCH 2/3 V2] b43: Fix unload oops if firmware is not available

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Message-Id: <1389561099-17181-3-git-send-email-Larry.Finger@lwfinger.net>
Date:	Sun, 12 Jan 2014 15:11:38 -0600
From:	Larry Finger <Larry.Finger@...inger.net>
To:	linville@...driver.com
Cc:	linux-wireless@...r.kernel.org,
	Larry Finger <Larry.Finger@...inger.net>,
	netdev@...r.kernel.org, Stable <stable@...r.kernel.org>
Subject: [PATCH 2/3 V2] b43: Fix unload oops if firmware is not available

The asyncronous firmware load uses a completion struct to hold firmware
processing until the user-space routines are up and running. There is.
however, a problem in that the waiter is nevered canceled during teardown.
As a result, unloading the driver when firmware is not available causes an oops.

To be able to access the completion structure at teardown, it had to be moved
into the b43_wldev structure.

This patch also fixes a typo in a comment.

Signed-off-by: Larry Finger <Larry.Finger@...inger.net>
Cc: Stable <stable@...r.kernel.org>
---

V2 - Addresses the comments of Ben Hutchings and removes the race condition.

 drivers/net/wireless/b43/b43.h  |  4 ++--
 drivers/net/wireless/b43/main.c | 10 +++++-----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/b43/b43.h b/drivers/net/wireless/b43/b43.h
index 7f3d461..54376fd 100644
--- a/drivers/net/wireless/b43/b43.h
+++ b/drivers/net/wireless/b43/b43.h
@@ -731,8 +731,6 @@ enum b43_firmware_file_type {
 struct b43_request_fw_context {
 	/* The device we are requesting the fw for. */
 	struct b43_wldev *dev;
-	/* a completion event structure needed if this call is asynchronous */
-	struct completion fw_load_complete;
 	/* a pointer to the firmware object */
 	const struct firmware *blob;
 	/* The type of firmware to request. */
@@ -809,6 +807,8 @@ enum {
 struct b43_wldev {
 	struct b43_bus_dev *dev;
 	struct b43_wl *wl;
+	/* a completion event structure needed if this call is asynchronous */
+	struct completion fw_load_complete;
 
 	/* The device initialization status.
 	 * Use b43_status() to query. */
diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 86b2030..c75237e 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -2070,6 +2070,7 @@ void b43_do_release_fw(struct b43_firmware_file *fw)
 
 static void b43_release_firmware(struct b43_wldev *dev)
 {
+	complete(&dev->fw_load_complete);
 	b43_do_release_fw(&dev->fw.ucode);
 	b43_do_release_fw(&dev->fw.pcm);
 	b43_do_release_fw(&dev->fw.initvals);
@@ -2095,7 +2096,7 @@ static void b43_fw_cb(const struct firmware *firmware, void *context)
 	struct b43_request_fw_context *ctx = context;
 
 	ctx->blob = firmware;
-	complete(&ctx->fw_load_complete);
+	complete(&ctx->dev->fw_load_complete);
 }
 
 int b43_do_request_fw(struct b43_request_fw_context *ctx,
@@ -2142,7 +2143,7 @@ int b43_do_request_fw(struct b43_request_fw_context *ctx,
 	}
 	if (async) {
 		/* do this part asynchronously */
-		init_completion(&ctx->fw_load_complete);
+		init_completion(&ctx->dev->fw_load_complete);
 		err = request_firmware_nowait(THIS_MODULE, 1, ctx->fwname,
 					      ctx->dev->dev->dev, GFP_KERNEL,
 					      ctx, b43_fw_cb);
@@ -2150,12 +2151,11 @@ int b43_do_request_fw(struct b43_request_fw_context *ctx,
 			pr_err("Unable to load firmware\n");
 			return err;
 		}
-		/* stall here until fw ready */
-		wait_for_completion(&ctx->fw_load_complete);
+		wait_for_completion(&ctx->dev->fw_load_complete);
 		if (ctx->blob)
 			goto fw_ready;
 	/* On some ARM systems, the async request will fail, but the next sync
-	 * request works. For this reason, we dall through here
+	 * request works. For this reason, we fall through here
 	 */
 	}
 	err = request_firmware(&ctx->blob, ctx->fwname,
-- 
1.8.4

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