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Date: Sat, 15 Apr 2023 16:42:51 +0200
From: Gerhard Engleder <gerhard@...leder-embedded.com>
To: netdev@...r.kernel.org, bpf@...r.kernel.org
Cc: davem@...emloft.net, kuba@...nel.org, edumazet@...gle.com,
pabeni@...hat.com, bjorn@...nel.org, magnus.karlsson@...el.com,
maciej.fijalkowski@...el.com, jonathan.lemon@...il.com,
Gerhard Engleder <gerhard@...leder-embedded.com>
Subject: [PATCH net-next v2 1/6] tsnep: Replace modulo operation with mask
TX/RX ring size is static and power of 2 to enable compiler to optimize
modulo operation to mask operation. Make this optimization already in
the code and don't rely on the compiler.
Signed-off-by: Gerhard Engleder <gerhard@...leder-embedded.com>
---
drivers/net/ethernet/engleder/tsnep.h | 1 +
drivers/net/ethernet/engleder/tsnep_main.c | 28 +++++++++++-----------
2 files changed, 15 insertions(+), 14 deletions(-)
diff --git a/drivers/net/ethernet/engleder/tsnep.h b/drivers/net/ethernet/engleder/tsnep.h
index 058c2bcf31a7..1de26aec78d3 100644
--- a/drivers/net/ethernet/engleder/tsnep.h
+++ b/drivers/net/ethernet/engleder/tsnep.h
@@ -18,6 +18,7 @@
#define TSNEP "tsnep"
#define TSNEP_RING_SIZE 256
+#define TSNEP_RING_MASK (TSNEP_RING_SIZE - 1)
#define TSNEP_RING_RX_REFILL 16
#define TSNEP_RING_RX_REUSE (TSNEP_RING_SIZE - TSNEP_RING_SIZE / 4)
#define TSNEP_RING_ENTRIES_PER_PAGE (PAGE_SIZE / TSNEP_DESC_SIZE)
diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c
index ed1b6102cfeb..3d15e673894a 100644
--- a/drivers/net/ethernet/engleder/tsnep_main.c
+++ b/drivers/net/ethernet/engleder/tsnep_main.c
@@ -292,7 +292,7 @@ static int tsnep_tx_ring_init(struct tsnep_tx *tx)
}
for (i = 0; i < TSNEP_RING_SIZE; i++) {
entry = &tx->entry[i];
- next_entry = &tx->entry[(i + 1) % TSNEP_RING_SIZE];
+ next_entry = &tx->entry[(i + 1) & TSNEP_RING_MASK];
entry->desc->next = __cpu_to_le64(next_entry->desc_dma);
}
@@ -381,7 +381,7 @@ static int tsnep_tx_map(struct sk_buff *skb, struct tsnep_tx *tx, int count)
int i;
for (i = 0; i < count; i++) {
- entry = &tx->entry[(tx->write + i) % TSNEP_RING_SIZE];
+ entry = &tx->entry[(tx->write + i) & TSNEP_RING_MASK];
if (!i) {
len = skb_headlen(skb);
@@ -419,7 +419,7 @@ static int tsnep_tx_unmap(struct tsnep_tx *tx, int index, int count)
int i;
for (i = 0; i < count; i++) {
- entry = &tx->entry[(index + i) % TSNEP_RING_SIZE];
+ entry = &tx->entry[(index + i) & TSNEP_RING_MASK];
if (entry->len) {
if (entry->type & TSNEP_TX_TYPE_SKB)
@@ -481,9 +481,9 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
for (i = 0; i < count; i++)
- tsnep_tx_activate(tx, (tx->write + i) % TSNEP_RING_SIZE, length,
+ tsnep_tx_activate(tx, (tx->write + i) & TSNEP_RING_MASK, length,
i == count - 1);
- tx->write = (tx->write + count) % TSNEP_RING_SIZE;
+ tx->write = (tx->write + count) & TSNEP_RING_MASK;
skb_tx_timestamp(skb);
@@ -516,7 +516,7 @@ static int tsnep_xdp_tx_map(struct xdp_frame *xdpf, struct tsnep_tx *tx,
frag = NULL;
len = xdpf->len;
for (i = 0; i < count; i++) {
- entry = &tx->entry[(tx->write + i) % TSNEP_RING_SIZE];
+ entry = &tx->entry[(tx->write + i) & TSNEP_RING_MASK];
if (type & TSNEP_TX_TYPE_XDP_NDO) {
data = unlikely(frag) ? skb_frag_address(frag) :
xdpf->data;
@@ -589,9 +589,9 @@ static bool tsnep_xdp_xmit_frame_ring(struct xdp_frame *xdpf,
length = retval;
for (i = 0; i < count; i++)
- tsnep_tx_activate(tx, (tx->write + i) % TSNEP_RING_SIZE, length,
+ tsnep_tx_activate(tx, (tx->write + i) & TSNEP_RING_MASK, length,
i == count - 1);
- tx->write = (tx->write + count) % TSNEP_RING_SIZE;
+ tx->write = (tx->write + count) & TSNEP_RING_MASK;
/* descriptor properties shall be valid before hardware is notified */
dma_wmb();
@@ -691,7 +691,7 @@ static bool tsnep_tx_poll(struct tsnep_tx *tx, int napi_budget)
/* xdpf is union with skb */
entry->skb = NULL;
- tx->read = (tx->read + count) % TSNEP_RING_SIZE;
+ tx->read = (tx->read + count) & TSNEP_RING_MASK;
tx->packets++;
tx->bytes += length + ETH_FCS_LEN;
@@ -839,7 +839,7 @@ static int tsnep_rx_ring_init(struct tsnep_rx *rx)
for (i = 0; i < TSNEP_RING_SIZE; i++) {
entry = &rx->entry[i];
- next_entry = &rx->entry[(i + 1) % TSNEP_RING_SIZE];
+ next_entry = &rx->entry[(i + 1) & TSNEP_RING_MASK];
entry->desc->next = __cpu_to_le64(next_entry->desc_dma);
}
@@ -925,7 +925,7 @@ static int tsnep_rx_refill(struct tsnep_rx *rx, int count, bool reuse)
int retval;
for (i = 0; i < count && !alloc_failed; i++) {
- index = (rx->write + i) % TSNEP_RING_SIZE;
+ index = (rx->write + i) & TSNEP_RING_MASK;
retval = tsnep_rx_alloc_buffer(rx, index);
if (unlikely(retval)) {
@@ -945,7 +945,7 @@ static int tsnep_rx_refill(struct tsnep_rx *rx, int count, bool reuse)
}
if (enable) {
- rx->write = (rx->write + i) % TSNEP_RING_SIZE;
+ rx->write = (rx->write + i) & TSNEP_RING_MASK;
/* descriptor properties shall be valid before hardware is
* notified
@@ -1090,7 +1090,7 @@ static int tsnep_rx_poll(struct tsnep_rx *rx, struct napi_struct *napi,
* empty RX ring, thus buffer cannot be used for
* RX processing
*/
- rx->read = (rx->read + 1) % TSNEP_RING_SIZE;
+ rx->read = (rx->read + 1) & TSNEP_RING_MASK;
desc_available++;
rx->dropped++;
@@ -1117,7 +1117,7 @@ static int tsnep_rx_poll(struct tsnep_rx *rx, struct napi_struct *napi,
*/
length -= TSNEP_RX_INLINE_METADATA_SIZE;
- rx->read = (rx->read + 1) % TSNEP_RING_SIZE;
+ rx->read = (rx->read + 1) & TSNEP_RING_MASK;
desc_available++;
if (prog) {
--
2.30.2
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