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

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Date:   Mon, 26 Feb 2018 07:47:43 +0100
From:   Jens Wiklander <jens.wiklander@...aro.org>
To:     Peng Fan <van.freenix@...il.com>
Cc:     Peng Fan <peng.fan@....com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-imx@....com
Subject: Re: [PATCH] tee: correct max value for id allocation

On Fri, Feb 23, 2018 at 3:43 AM, Peng Fan <van.freenix@...il.com> wrote:
> Hi Jens,
>
> Any comments on this patch?
>
> Thanks,
> Peng

Sorry, forgot about this one. Looks good to me, I'll pick it up.

Thanks,
Jens

> 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
>>
>
> --