linux-kernel - Re: [PATCH] tee: correct max value for id allocation

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Date:   Fri, 23 Feb 2018 10:43:20 +0800
From:   Peng Fan <van.freenix@...il.com>
To:     Peng Fan <peng.fan@....com>
Cc:     jens.wiklander@...aro.org, linux-kernel@...r.kernel.org,
        linux-imx@....com
Subject: Re: [PATCH] tee: correct max value for id allocation

Hi Jens,

Any comments on this patch?

Thanks,
Peng
On Mon, Jan 15, 2018 at 05:27:35PM +0800, Peng Fan wrote:
>The privileged dev id range is [TEE_NUM_DEVICES / 2, TEE_NUM_DEVICES).
>The non-privileged dev id range is [0, TEE_NUM_DEVICES / 2).
>
>So when finding a slot for them, need to use different max value.
>
>Signed-off-by: Peng Fan <peng.fan@....com>
>Cc: Jens Wiklander <jens.wiklander@...aro.org>
>---
> drivers/tee/tee_core.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
>diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
>index 3d49ac2e3c84..d1f4ecdbc8cc 100644
>--- a/drivers/tee/tee_core.c
>+++ b/drivers/tee/tee_core.c
>@@ -701,7 +701,7 @@ struct tee_device *tee_device_alloc(const struct tee_desc *teedesc,
> {
> 	struct tee_device *teedev;
> 	void *ret;
>-	int rc;
>+	int rc, max_id;
> 	int offs = 0;
> 
> 	if (!teedesc || !teedesc->name || !teedesc->ops ||
>@@ -715,16 +715,20 @@ struct tee_device *tee_device_alloc(const struct tee_desc *teedesc,
> 		goto err;
> 	}
> 
>-	if (teedesc->flags & TEE_DESC_PRIVILEGED)
>+	max_id = TEE_NUM_DEVICES / 2;
>+
>+	if (teedesc->flags & TEE_DESC_PRIVILEGED) {
> 		offs = TEE_NUM_DEVICES / 2;
>+		max_id = TEE_NUM_DEVICES;
>+	}
> 
> 	spin_lock(&driver_lock);
>-	teedev->id = find_next_zero_bit(dev_mask, TEE_NUM_DEVICES, offs);
>-	if (teedev->id < TEE_NUM_DEVICES)
>+	teedev->id = find_next_zero_bit(dev_mask, max_id, offs);
>+	if (teedev->id < max_id)
> 		set_bit(teedev->id, dev_mask);
> 	spin_unlock(&driver_lock);
> 
>-	if (teedev->id >= TEE_NUM_DEVICES) {
>+	if (teedev->id >= max_id) {
> 		ret = ERR_PTR(-ENOMEM);
> 		goto err;
> 	}
>-- 
>2.14.1
>

--