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gve: DQO: avoid unused variable warnings
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The use of dma_unmap_addr()/dma_unmap_len() in the driver causes
multiple warnings when these macros are defined as empty, e.g.
in an ARCH=i386 allmodconfig build:

drivers/net/ethernet/google/gve/gve_tx_dqo.c: In function 'gve_tx_add_skb_no_copy_dqo':
drivers/net/ethernet/google/gve/gve_tx_dqo.c:494:40: error: unused variable 'buf' [-Werror=unused-variable]
  494 |                 struct gve_tx_dma_buf *buf =

This is not how the NEED_DMA_MAP_STATE macros are meant to work,
as they rely on never using local variables or a temporary structure
like gve_tx_dma_buf.

Remote the gve_tx_dma_buf definition and open-code the contents
in all places to avoid the warning. This causes some rather long
lines but otherwise ends up making the driver slightly smaller.

Fixes: a57e5de ("gve: DQO: Add TX path")
Link: https://lore.kernel.org/netdev/20210723231957.1113800-1-bcf@google.com/
Link: https://lore.kernel.org/netdev/20210721151100.2042139-1-arnd@kernel.org/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Arnd Bergmann authored and David S. Miller committed Sep 28, 2021
1 parent af3826d commit 1e0083b
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Showing 3 changed files with 54 additions and 66 deletions.
13 changes: 6 additions & 7 deletions drivers/net/ethernet/google/gve/gve.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -224,19 +224,17 @@ struct gve_tx_iovec {
u32 iov_padding; /* padding associated with this segment */
};

struct gve_tx_dma_buf {
DEFINE_DMA_UNMAP_ADDR(dma);
DEFINE_DMA_UNMAP_LEN(len);
};

/* Tracks the memory in the fifo occupied by the skb. Mapped 1:1 to a desc
* ring entry but only used for a pkt_desc not a seg_desc
*/
struct gve_tx_buffer_state {
struct sk_buff *skb; /* skb for this pkt */
union {
struct gve_tx_iovec iov[GVE_TX_MAX_IOVEC]; /* segments of this pkt */
struct gve_tx_dma_buf buf;
struct {
DEFINE_DMA_UNMAP_ADDR(dma);
DEFINE_DMA_UNMAP_LEN(len);
};
};
};

Expand Down Expand Up @@ -280,7 +278,8 @@ struct gve_tx_pending_packet_dqo {
* All others correspond to `skb`'s frags and should be unmapped with
* `dma_unmap_page`.
*/
struct gve_tx_dma_buf bufs[MAX_SKB_FRAGS + 1];
DEFINE_DMA_UNMAP_ADDR(dma[MAX_SKB_FRAGS + 1]);
DEFINE_DMA_UNMAP_LEN(len[MAX_SKB_FRAGS + 1]);
u16 num_bufs;

/* Linked list index to next element in the list, or -1 if none */
Expand Down
23 changes: 10 additions & 13 deletions drivers/net/ethernet/google/gve/gve_tx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -303,15 +303,15 @@ static inline int gve_skb_fifo_bytes_required(struct gve_tx_ring *tx,
static void gve_tx_unmap_buf(struct device *dev, struct gve_tx_buffer_state *info)
{
if (info->skb) {
dma_unmap_single(dev, dma_unmap_addr(&info->buf, dma),
dma_unmap_len(&info->buf, len),
dma_unmap_single(dev, dma_unmap_addr(info, dma),
dma_unmap_len(info, len),
DMA_TO_DEVICE);
dma_unmap_len_set(&info->buf, len, 0);
dma_unmap_len_set(info, len, 0);
} else {
dma_unmap_page(dev, dma_unmap_addr(&info->buf, dma),
dma_unmap_len(&info->buf, len),
dma_unmap_page(dev, dma_unmap_addr(info, dma),
dma_unmap_len(info, len),
DMA_TO_DEVICE);
dma_unmap_len_set(&info->buf, len, 0);
dma_unmap_len_set(info, len, 0);
}
}

Expand Down Expand Up @@ -491,7 +491,6 @@ static int gve_tx_add_skb_no_copy(struct gve_priv *priv, struct gve_tx_ring *tx,
struct gve_tx_buffer_state *info;
bool is_gso = skb_is_gso(skb);
u32 idx = tx->req & tx->mask;
struct gve_tx_dma_buf *buf;
u64 addr;
u32 len;
int i;
Expand All @@ -515,9 +514,8 @@ static int gve_tx_add_skb_no_copy(struct gve_priv *priv, struct gve_tx_ring *tx,
tx->dma_mapping_error++;
goto drop;
}
buf = &info->buf;
dma_unmap_len_set(buf, len, len);
dma_unmap_addr_set(buf, dma, addr);
dma_unmap_len_set(info, len, len);
dma_unmap_addr_set(info, dma, addr);

payload_nfrags = shinfo->nr_frags;
if (hlen < len) {
Expand Down Expand Up @@ -549,10 +547,9 @@ static int gve_tx_add_skb_no_copy(struct gve_priv *priv, struct gve_tx_ring *tx,
tx->dma_mapping_error++;
goto unmap_drop;
}
buf = &tx->info[idx].buf;
tx->info[idx].skb = NULL;
dma_unmap_len_set(buf, len, len);
dma_unmap_addr_set(buf, dma, addr);
dma_unmap_len_set(&tx->info[idx], len, len);
dma_unmap_addr_set(&tx->info[idx], dma, addr);

gve_tx_fill_seg_desc(seg_desc, skb, is_gso, len, addr);
}
Expand Down
84 changes: 38 additions & 46 deletions drivers/net/ethernet/google/gve/gve_tx_dqo.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -85,18 +85,16 @@ static void gve_tx_clean_pending_packets(struct gve_tx_ring *tx)
int j;

for (j = 0; j < cur_state->num_bufs; j++) {
struct gve_tx_dma_buf *buf = &cur_state->bufs[j];

if (j == 0) {
dma_unmap_single(tx->dev,
dma_unmap_addr(buf, dma),
dma_unmap_len(buf, len),
DMA_TO_DEVICE);
dma_unmap_addr(cur_state, dma[j]),
dma_unmap_len(cur_state, len[j]),
DMA_TO_DEVICE);
} else {
dma_unmap_page(tx->dev,
dma_unmap_addr(buf, dma),
dma_unmap_len(buf, len),
DMA_TO_DEVICE);
dma_unmap_addr(cur_state, dma[j]),
dma_unmap_len(cur_state, len[j]),
DMA_TO_DEVICE);
}
}
if (cur_state->skb) {
Expand Down Expand Up @@ -457,15 +455,15 @@ static int gve_tx_add_skb_no_copy_dqo(struct gve_tx_ring *tx,
const bool is_gso = skb_is_gso(skb);
u32 desc_idx = tx->dqo_tx.tail;

struct gve_tx_pending_packet_dqo *pending_packet;
struct gve_tx_pending_packet_dqo *pkt;
struct gve_tx_metadata_dqo metadata;
s16 completion_tag;
int i;

pending_packet = gve_alloc_pending_packet(tx);
pending_packet->skb = skb;
pending_packet->num_bufs = 0;
completion_tag = pending_packet - tx->dqo.pending_packets;
pkt = gve_alloc_pending_packet(tx);
pkt->skb = skb;
pkt->num_bufs = 0;
completion_tag = pkt - tx->dqo.pending_packets;

gve_extract_tx_metadata_dqo(skb, &metadata);
if (is_gso) {
Expand Down Expand Up @@ -493,27 +491,23 @@ static int gve_tx_add_skb_no_copy_dqo(struct gve_tx_ring *tx,

/* Map the linear portion of skb */
{
struct gve_tx_dma_buf *buf =
&pending_packet->bufs[pending_packet->num_bufs];
u32 len = skb_headlen(skb);
dma_addr_t addr;

addr = dma_map_single(tx->dev, skb->data, len, DMA_TO_DEVICE);
if (unlikely(dma_mapping_error(tx->dev, addr)))
goto err;

dma_unmap_len_set(buf, len, len);
dma_unmap_addr_set(buf, dma, addr);
++pending_packet->num_bufs;
dma_unmap_len_set(pkt, len[pkt->num_bufs], len);
dma_unmap_addr_set(pkt, dma[pkt->num_bufs], addr);
++pkt->num_bufs;

gve_tx_fill_pkt_desc_dqo(tx, &desc_idx, skb, len, addr,
completion_tag,
/*eop=*/shinfo->nr_frags == 0, is_gso);
}

for (i = 0; i < shinfo->nr_frags; i++) {
struct gve_tx_dma_buf *buf =
&pending_packet->bufs[pending_packet->num_bufs];
const skb_frag_t *frag = &shinfo->frags[i];
bool is_eop = i == (shinfo->nr_frags - 1);
u32 len = skb_frag_size(frag);
Expand All @@ -523,9 +517,9 @@ static int gve_tx_add_skb_no_copy_dqo(struct gve_tx_ring *tx,
if (unlikely(dma_mapping_error(tx->dev, addr)))
goto err;

dma_unmap_len_set(buf, len, len);
dma_unmap_addr_set(buf, dma, addr);
++pending_packet->num_bufs;
dma_unmap_len_set(pkt, len[pkt->num_bufs], len);
dma_unmap_addr_set(pkt, dma[pkt->num_bufs], addr);
++pkt->num_bufs;

gve_tx_fill_pkt_desc_dqo(tx, &desc_idx, skb, len, addr,
completion_tag, is_eop, is_gso);
Expand All @@ -552,22 +546,23 @@ static int gve_tx_add_skb_no_copy_dqo(struct gve_tx_ring *tx,
return 0;

err:
for (i = 0; i < pending_packet->num_bufs; i++) {
struct gve_tx_dma_buf *buf = &pending_packet->bufs[i];

for (i = 0; i < pkt->num_bufs; i++) {
if (i == 0) {
dma_unmap_single(tx->dev, dma_unmap_addr(buf, dma),
dma_unmap_len(buf, len),
dma_unmap_single(tx->dev,
dma_unmap_addr(pkt, dma[i]),
dma_unmap_len(pkt, len[i]),
DMA_TO_DEVICE);
} else {
dma_unmap_page(tx->dev, dma_unmap_addr(buf, dma),
dma_unmap_len(buf, len), DMA_TO_DEVICE);
dma_unmap_page(tx->dev,
dma_unmap_addr(pkt, dma[i]),
dma_unmap_len(pkt, len[i]),
DMA_TO_DEVICE);
}
}

pending_packet->skb = NULL;
pending_packet->num_bufs = 0;
gve_free_pending_packet(tx, pending_packet);
pkt->skb = NULL;
pkt->num_bufs = 0;
gve_free_pending_packet(tx, pkt);

return -1;
}
Expand Down Expand Up @@ -725,12 +720,12 @@ static void add_to_list(struct gve_tx_ring *tx, struct gve_index_list *list,

static void remove_from_list(struct gve_tx_ring *tx,
struct gve_index_list *list,
struct gve_tx_pending_packet_dqo *pending_packet)
struct gve_tx_pending_packet_dqo *pkt)
{
s16 prev_index, next_index;

prev_index = pending_packet->prev;
next_index = pending_packet->next;
prev_index = pkt->prev;
next_index = pkt->next;

if (prev_index == -1) {
/* Node is head */
Expand All @@ -747,21 +742,18 @@ static void remove_from_list(struct gve_tx_ring *tx,
}

static void gve_unmap_packet(struct device *dev,
struct gve_tx_pending_packet_dqo *pending_packet)
struct gve_tx_pending_packet_dqo *pkt)
{
struct gve_tx_dma_buf *buf;
int i;

/* SKB linear portion is guaranteed to be mapped */
buf = &pending_packet->bufs[0];
dma_unmap_single(dev, dma_unmap_addr(buf, dma),
dma_unmap_len(buf, len), DMA_TO_DEVICE);
for (i = 1; i < pending_packet->num_bufs; i++) {
buf = &pending_packet->bufs[i];
dma_unmap_page(dev, dma_unmap_addr(buf, dma),
dma_unmap_len(buf, len), DMA_TO_DEVICE);
dma_unmap_single(dev, dma_unmap_addr(pkt, dma[0]),
dma_unmap_len(pkt, len[0]), DMA_TO_DEVICE);
for (i = 1; i < pkt->num_bufs; i++) {
dma_unmap_page(dev, dma_unmap_addr(pkt, dma[i]),
dma_unmap_len(pkt, len[i]), DMA_TO_DEVICE);
}
pending_packet->num_bufs = 0;
pkt->num_bufs = 0;
}

/* Completion types and expected behavior:
Expand Down

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