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| author | Stephen Hemminger <stephen@networkplumber.org> | 2024-01-25 16:25:11 -0800 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2024-01-30 12:02:32 +0100 |
| commit | 3f3ebe53620818f6e9b029850cb47b96a4ac5b3b (patch) | |
| tree | c0f1ff282d3068a586ac73525e2d42aae5688590 /drivers/net/tun.c | |
| parent | e8166eb24692ddac08ed3a401d3d09e9b4443642 (diff) | |
| download | lwn-3f3ebe53620818f6e9b029850cb47b96a4ac5b3b.tar.gz lwn-3f3ebe53620818f6e9b029850cb47b96a4ac5b3b.zip | |
net/tun: use reciprocal_scale
Use the inline function reciprocal_scale rather than open coding
the scale optimization. Also, remove unnecessary initializations.
Resulting compiled code is unchanged (according to godbolt).
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20240126002550.169608-1-stephen@networkplumber.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'drivers/net/tun.c')
| -rw-r--r-- | drivers/net/tun.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 4a4f8c8e79fa..e335ece47dec 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -54,6 +54,7 @@ #include <linux/if_tun.h> #include <linux/if_vlan.h> #include <linux/crc32.h> +#include <linux/math.h> #include <linux/nsproxy.h> #include <linux/virtio_net.h> #include <linux/rcupdate.h> @@ -523,8 +524,7 @@ static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb) { struct tun_flow_entry *e; - u32 txq = 0; - u32 numqueues = 0; + u32 txq, numqueues; numqueues = READ_ONCE(tun->numqueues); @@ -534,8 +534,7 @@ static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb) tun_flow_save_rps_rxhash(e, txq); txq = e->queue_index; } else { - /* use multiply and shift instead of expensive divide */ - txq = ((u64)txq * numqueues) >> 32; + txq = reciprocal_scale(txq, numqueues); } return txq; |