Am 26.10.21 um 13:52 schrieb guangming.cao@xxxxxxxxxxxx:
From: Guangming Cao <Guangming.Cao@xxxxxxxxxxxx>
On Tue, 2021-10-26 at 13:18 +0200, Christian König wrote:
Am 14.10.21 um 12:25 schrieb guangming.cao@xxxxxxxxxxxx:
From: Guangming Cao <Guangming.Cao@xxxxxxxxxxxx>
In this patch(https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.freedesktop.org%2Fpatch%2F310349&data=04%7C01%7Cchristian.koenig%40amd.com%7C6652f423b96547b8321308d998772121%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637708459727236977%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=4EFg60sCxQzNuMKB0VjhbpvoeGlcAbofErMtcjPtIfw%3D&reserved=0),
it add a new IOCTL to support dma-buf user to set debug name.
But it also added a limitation of this IOCTL, it needs the
attachments of dmabuf should be empty, otherwise it will fail.
For the original series, the idea was that allowing name change
mid-use could confuse the users about the dma-buf.
However, the rest of the series also makes sure each dma-buf have a
unique
inode(https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.freedesktop.org%2Fpatch%2F310387%2F&data=04%7C01%7Cchristian.koenig%40amd.com%7C6652f423b96547b8321308d998772121%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637708459727236977%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=c%2Bbso%2BSxiPjwlv%2B9tAzA4x0gf5UktREhSiAsODFkihk%3D&reserved=0), and any
accounting
should probably use that, without relying on the name as much.
So, removing this restriction will let dma-buf userspace users to
use it
more comfortably and without any side effect.
Signed-off-by: Guangming Cao <Guangming.Cao@xxxxxxxxxxxx>
We could now cleanup the return value from dma_buf_set_name() into a
void since that function can't fail any more as far as I can see.
But that isn't mandatory I think, patch is Reviewed-by: Christian
König
<christian.koenig@xxxxxxx>
So, here is no need to check return value of 'strndup_user',
just return without error code if the almost impossible error occurs?
Good point, totally missed that one.
In that case I'm going to push the patch to drm-misc-next as is.
Regards,
Christian.
Guangming.
Regards,
Christian.
---
drivers/dma-buf/dma-buf.c | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 511fe0d217a0..5fbb3a2068a3 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -325,10 +325,8 @@ static __poll_t dma_buf_poll(struct file
*file, poll_table *poll)
/**
* dma_buf_set_name - Set a name to a specific dma_buf to track
the usage.
- * The name of the dma-buf buffer can only be set when the dma-buf
is not
- * attached to any devices. It could theoritically support
changing the
- * name of the dma-buf if the same piece of memory is used for
multiple
- * purpose between different devices.
+ * It could support changing the name of the dma-buf if the same
+ * piece of memory is used for multiple purpose between different
devices.
*
* @dmabuf: [in] dmabuf buffer that will be renamed.
* @buf: [in] A piece of userspace memory that contains
the name of
@@ -341,25 +339,16 @@ static __poll_t dma_buf_poll(struct file
*file, poll_table *poll)
static long dma_buf_set_name(struct dma_buf *dmabuf, const char
__user *buf)
{
char *name = strndup_user(buf, DMA_BUF_NAME_LEN);
- long ret = 0;
if (IS_ERR(name))
return PTR_ERR(name);
- dma_resv_lock(dmabuf->resv, NULL);
- if (!list_empty(&dmabuf->attachments)) {
- ret = -EBUSY;
- kfree(name);
- goto out_unlock;
- }
spin_lock(&dmabuf->name_lock);
kfree(dmabuf->name);
dmabuf->name = name;
spin_unlock(&dmabuf->name_lock);
-out_unlock:
- dma_resv_unlock(dmabuf->resv);
- return ret;
+ return 0;
}
static long dma_buf_ioctl(struct file *file,
