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Refactor ena_tx_map_mbuf() function

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There is no guarantee from bus_dmamap_load_mbuf_sg() for matching
mbuf chain segments to dma physical segments.

This patch ensure correctly mapping to LLQ header and DMA segments.

Submitted by: Ido Segev <idose@amazon.com>
Obtained from: Amazon, Inc.
This commit is contained in:
Marcin Wojtas 2020-05-26 16:05:42 +00:00
parent 9bf7da9517
commit 7381a86f47
1 changed files with 28 additions and 61 deletions
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89
sys/dev/ena/ena_datapath.c
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@ -812,9 +812,8 @@ ena_tx_map_mbuf(struct ena_ring *tx_ring, struct ena_tx_buffer *tx_info,
struct ena_com_buf *ena_buf;
bus_dma_segment_t segs[ENA_BUS_DMA_SEGS];
size_t iseg = 0;
uint32_t mbuf_head_len, frag_len;
uint16_t push_len = 0;
uint16_t delta = 0;
uint32_t mbuf_head_len;
uint16_t offset;
int rc, nsegs;
mbuf_head_len = mbuf->m_len;
@ -833,7 +832,6 @@ ena_tx_map_mbuf(struct ena_ring *tx_ring, struct ena_tx_buffer *tx_info,
goto dma_error;
}
if (tx_ring->tx_mem_queue_type == ENA_ADMIN_PLACEMENT_POLICY_DEV) {
/*
* When the device is LLQ mode, the driver will copy
@ -845,44 +843,48 @@ ena_tx_map_mbuf(struct ena_ring *tx_ring, struct ena_tx_buffer *tx_info,
* First check if header fits in the mbuf. If not, copy it to
* separate buffer that will be holding linearized data.
*/
push_len = min_t(uint32_t, mbuf->m_pkthdr.len,
tx_ring->tx_max_header_size);
*header_len = push_len;
*header_len = min_t(uint32_t, mbuf->m_pkthdr.len, tx_ring->tx_max_header_size);
/* If header is in linear space, just point into mbuf's data. */
if (likely(push_len <= mbuf_head_len)) {
if (likely(*header_len <= mbuf_head_len)) {
*push_hdr = mbuf->m_data;
/*
* Otherwise, copy whole portion of header from multiple mbufs
* to intermediate buffer.
*/
} else {
m_copydata(mbuf, 0, push_len,
tx_ring->push_buf_intermediate_buf);
m_copydata(mbuf, 0, *header_len, tx_ring->push_buf_intermediate_buf);
*push_hdr = tx_ring->push_buf_intermediate_buf;
counter_u64_add(tx_ring->tx_stats.llq_buffer_copy, 1);
delta = push_len - mbuf_head_len;
}
ena_trace(ENA_DBG | ENA_TXPTH,
"mbuf: %p header_buf->vaddr: %p push_len: %d\n",
mbuf, *push_hdr, push_len);
mbuf, *push_hdr, *header_len);
/*
* If header was in linear memory space, map for the dma rest of the data
* in the first mbuf of the mbuf chain.
*/
if (mbuf_head_len > push_len) {
ena_buf->paddr = segs[iseg].ds_addr + push_len;
ena_buf->len = segs[iseg].ds_len - push_len;
ena_buf++;
tx_info->num_of_bufs++;
/* If packet is fitted in LLQ header, no need for DMA segments. */
if (mbuf->m_pkthdr.len <= tx_ring->tx_max_header_size) {
return (0);
} else {
offset = tx_ring->tx_max_header_size;
/*
* As Header part is mapped to LLQ header, we can skip it and just
* map the residuum of the mbuf to DMA Segments.
*/
while (offset > 0) {
if (offset >= segs[iseg].ds_len) {
offset -= segs[iseg].ds_len;
} else {
ena_buf->paddr = segs[iseg].ds_addr + offset;
ena_buf->len = segs[iseg].ds_len - offset;
ena_buf++;
tx_info->num_of_bufs++;
offset = 0;
}
iseg++;
}
}
/*
* Advance the seg index as either the 1st mbuf was mapped or is
* a part of push_hdr.
*/
iseg++;
} else {
*push_hdr = NULL;
/*
@ -895,41 +897,6 @@ ena_tx_map_mbuf(struct ena_ring *tx_ring, struct ena_tx_buffer *tx_info,
*header_len = 0;
}
/*
* If header is in non linear space (delta > 0), then skip mbufs
* containing header and map the last one containing both header and the
* packet data.
* The first segment is already counted in.
* If LLQ is not supported, the loop will be skipped.
*/
while (delta > 0) {
frag_len = segs[iseg].ds_len;
/*
* If whole segment contains header just move to the
* next one and reduce delta.
*/
if (unlikely(delta >= frag_len)) {
delta -= frag_len;
} else {
/*
* Map rest of the packet data that was contained in
* the mbuf.
*/
ena_buf->paddr = segs[iseg].ds_addr + delta;
ena_buf->len = frag_len - delta;
ena_buf++;
tx_info->num_of_bufs++;
delta = 0;
}
iseg++;
}
if (mbuf == NULL) {
return (0);
}
/* Map rest of the mbuf */
while (iseg < nsegs) {
ena_buf->paddr = segs[iseg].ds_addr;