| Message ID | 20250120-tun-v4-7-ee81dda03d7f@daynix.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | tun: Unify vnet implementation | expand |
Akihiko Odaki wrote: > tap_get_user() used to track the length of iov_iter with another > variable. We can use iov_iter_count() to determine the current length > to avoid such chores. > > Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com> > --- > drivers/net/tap.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/tap.c b/drivers/net/tap.c > index 5aa41d5f7765a6dcf185bccd3cba2299bad89398..061c2f27dfc83f5e6d0bea4da0e845cc429b1fd8 100644 > --- a/drivers/net/tap.c > +++ b/drivers/net/tap.c > @@ -641,7 +641,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, > struct sk_buff *skb; > struct tap_dev *tap; > unsigned long total_len = iov_iter_count(from); > - unsigned long len = total_len; > + unsigned long len; > int err; > struct virtio_net_hdr vnet_hdr = { 0 }; > int vnet_hdr_len = 0; > @@ -655,9 +655,8 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, > vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); > > err = -EINVAL; > - if (len < vnet_hdr_len) > + if (iov_iter_count(from) < vnet_hdr_len) > goto err; > - len -= vnet_hdr_len; > > err = -EFAULT; > if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from)) > @@ -671,10 +670,12 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, > tap16_to_cpu(q, vnet_hdr.csum_start) + > tap16_to_cpu(q, vnet_hdr.csum_offset) + 2); > err = -EINVAL; > - if (tap16_to_cpu(q, vnet_hdr.hdr_len) > len) > + if (tap16_to_cpu(q, vnet_hdr.hdr_len) > iov_iter_count(from)) > goto err; > } > > + len = iov_iter_count(from); > + Since len is still used in the rest of the function, might as well use it from the start. I'd drop this patch.
diff --git a/drivers/net/tap.c b/drivers/net/tap.c index 5aa41d5f7765a6dcf185bccd3cba2299bad89398..061c2f27dfc83f5e6d0bea4da0e845cc429b1fd8 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -641,7 +641,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, struct sk_buff *skb; struct tap_dev *tap; unsigned long total_len = iov_iter_count(from); - unsigned long len = total_len; + unsigned long len; int err; struct virtio_net_hdr vnet_hdr = { 0 }; int vnet_hdr_len = 0; @@ -655,9 +655,8 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); err = -EINVAL; - if (len < vnet_hdr_len) + if (iov_iter_count(from) < vnet_hdr_len) goto err; - len -= vnet_hdr_len; err = -EFAULT; if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from)) @@ -671,10 +670,12 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, tap16_to_cpu(q, vnet_hdr.csum_start) + tap16_to_cpu(q, vnet_hdr.csum_offset) + 2); err = -EINVAL; - if (tap16_to_cpu(q, vnet_hdr.hdr_len) > len) + if (tap16_to_cpu(q, vnet_hdr.hdr_len) > iov_iter_count(from)) goto err; } + len = iov_iter_count(from); + err = -EINVAL; if (unlikely(len < ETH_HLEN)) goto err;
tap_get_user() used to track the length of iov_iter with another variable. We can use iov_iter_count() to determine the current length to avoid such chores. Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com> --- drivers/net/tap.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)