Am 2020-05-20 um 9:53 a.m. schrieb Aurabindo Pillai:
> The buffer allocated is of 1024 bytes. Allocate this from
> heap instead of stack.
>
> Also remove check for stack size since we're allocating from heap
>
> Signed-off-by: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
> Tested-by: Amber Lin <Amber.Lin@xxxxxxx>
See one comment inline. With that fixed, the patch is
Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
> ---
> drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c | 26 +++++++++++++++------
> 1 file changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> index f5fd18eacf0d..5aebe169f8c6 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> @@ -77,9 +77,11 @@ static ssize_t kfd_smi_ev_read(struct file *filep, char __user *user,
> int ret;
> size_t to_copy;
> struct kfd_smi_client *client = filep->private_data;
> - unsigned char buf[MAX_KFIFO_SIZE];
> + unsigned char *buf;
>
> - BUILD_BUG_ON(MAX_KFIFO_SIZE > 1024);
> + buf = kzalloc(MAX_KFIFO_SIZE * sizeof(*buf), GFP_KERNEL);
kzalloc is not necessary here, you could use kmalloc. The part of that
allocation that matters will be overwritten by kfifo_out.
Regards,
Felix
> + if (!buf)
> + return -ENOMEM;
>
> /* kfifo_to_user can sleep so we can't use spinlock protection around
> * it. Instead, we kfifo out as spinlocked then copy them to the user.
> @@ -88,19 +90,29 @@ static ssize_t kfd_smi_ev_read(struct file *filep, char __user *user,
> to_copy = kfifo_len(&client->fifo);
> if (!to_copy) {
> spin_unlock(&client->lock);
> - return -EAGAIN;
> + ret = -EAGAIN;
> + goto ret_err;
> }
> to_copy = min3(size, sizeof(buf), to_copy);
> ret = kfifo_out(&client->fifo, buf, to_copy);
> spin_unlock(&client->lock);
> - if (ret <= 0)
> - return -EAGAIN;
> + if (ret <= 0) {
> + ret = -EAGAIN;
> + goto ret_err;
> + }
>
> ret = copy_to_user(user, buf, to_copy);
> - if (ret)
> - return -EFAULT;
> + if (ret) {
> + ret = -EFAULT;
> + goto ret_err;
> + }
>
> + kfree(buf);
> return to_copy;
> +
> +ret_err:
> + kfree(buf);
> + return ret;
> }
>
> static ssize_t kfd_smi_ev_write(struct file *filep, const char __user *user,
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