Re: [PATCH] drm/amd/amdkfd: Fix large framesize for kfd_smi_ev_read()

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@amd.com Tested-by: Amber Lin Amber.Lin@amd.com

See one comment inline. With that fixed, the patch is

Reviewed-by: Felix Kuehling Felix.Kuehling@amd.com

---

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,