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Date: Wed, 23 Nov 2022 12:52:16 -0800
From: Anirudh Venkataramanan <anirudh.venkataramanan@...el.com>
To: netdev@...r.kernel.org
Cc: Ira Weiny <ira.weiny@...el.com>,
"Fabio M . De Francesco" <fmdefrancesco@...il.com>,
Anirudh Venkataramanan <anirudh.venkataramanan@...el.com>
Subject: [PATCH v2 net-next 3/6] cassini: Use page_address() instead of kmap_atomic()
Pages for Rx buffers are allocated in cas_page_alloc() using either
GFP_ATOMIC or GFP_KERNEL. Memory allocated with GFP_KERNEL/GFP_ATOMIC can't
come from highmem and so there's no need to kmap() them. Just use
page_address() instead. This makes the variable 'addr' unnecessary, so
remove it too.
Note that kmap_atomic() disables preemption and page-fault processing,
but page_address() doesn't. When removing uses of kmap_atomic(), one has to
check if the code being executed between the map/unmap implicitly depends
on page-faults and/or preemption being disabled. If yes, then code to
disable page-faults and/or preemption should also be added for functional
correctness. That however doesn't appear to be the case here, so just
page_address() is used.
I don't have hardware, so this change has only been compile tested.
Cc: Ira Weiny <ira.weiny@...el.com>
Cc: Fabio M. De Francesco <fmdefrancesco@...il.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@...el.com>
---
v1 -> v2: Update commit message
---
drivers/net/ethernet/sun/cassini.c | 34 ++++++++++--------------------
1 file changed, 11 insertions(+), 23 deletions(-)
diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c
index 0aca193..2f66cfc 100644
--- a/drivers/net/ethernet/sun/cassini.c
+++ b/drivers/net/ethernet/sun/cassini.c
@@ -1915,7 +1915,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
int off, swivel = RX_SWIVEL_OFF_VAL;
struct cas_page *page;
struct sk_buff *skb;
- void *addr, *crcaddr;
+ void *crcaddr;
__sum16 csum;
char *p;
@@ -1936,7 +1936,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
skb_reserve(skb, swivel);
p = skb->data;
- addr = crcaddr = NULL;
+ crcaddr = NULL;
if (hlen) { /* always copy header pages */
i = CAS_VAL(RX_COMP2_HDR_INDEX, words[1]);
page = cp->rx_pages[CAS_VAL(RX_INDEX_RING, i)][CAS_VAL(RX_INDEX_NUM, i)];
@@ -1948,12 +1948,10 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
i += cp->crc_size;
dma_sync_single_for_cpu(&cp->pdev->dev, page->dma_addr + off,
i, DMA_FROM_DEVICE);
- addr = cas_page_map(page->buffer);
- memcpy(p, addr + off, i);
+ memcpy(p, page_address(page->buffer) + off, i);
dma_sync_single_for_device(&cp->pdev->dev,
page->dma_addr + off, i,
DMA_FROM_DEVICE);
- cas_page_unmap(addr);
RX_USED_ADD(page, 0x100);
p += hlen;
swivel = 0;
@@ -1984,12 +1982,11 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
/* make sure we always copy a header */
swivel = 0;
if (p == (char *) skb->data) { /* not split */
- addr = cas_page_map(page->buffer);
- memcpy(p, addr + off, RX_COPY_MIN);
+ memcpy(p, page_address(page->buffer) + off,
+ RX_COPY_MIN);
dma_sync_single_for_device(&cp->pdev->dev,
page->dma_addr + off, i,
DMA_FROM_DEVICE);
- cas_page_unmap(addr);
off += RX_COPY_MIN;
swivel = RX_COPY_MIN;
RX_USED_ADD(page, cp->mtu_stride);
@@ -2036,10 +2033,8 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
RX_USED_ADD(page, hlen + cp->crc_size);
}
- if (cp->crc_size) {
- addr = cas_page_map(page->buffer);
- crcaddr = addr + off + hlen;
- }
+ if (cp->crc_size)
+ crcaddr = page_address(page->buffer) + off + hlen;
} else {
/* copying packet */
@@ -2061,12 +2056,10 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
i += cp->crc_size;
dma_sync_single_for_cpu(&cp->pdev->dev, page->dma_addr + off,
i, DMA_FROM_DEVICE);
- addr = cas_page_map(page->buffer);
- memcpy(p, addr + off, i);
+ memcpy(p, page_address(page->buffer) + off, i);
dma_sync_single_for_device(&cp->pdev->dev,
page->dma_addr + off, i,
DMA_FROM_DEVICE);
- cas_page_unmap(addr);
if (p == (char *) skb->data) /* not split */
RX_USED_ADD(page, cp->mtu_stride);
else
@@ -2081,20 +2074,17 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
page->dma_addr,
dlen + cp->crc_size,
DMA_FROM_DEVICE);
- addr = cas_page_map(page->buffer);
- memcpy(p, addr, dlen + cp->crc_size);
+ memcpy(p, page_address(page->buffer), dlen + cp->crc_size);
dma_sync_single_for_device(&cp->pdev->dev,
page->dma_addr,
dlen + cp->crc_size,
DMA_FROM_DEVICE);
- cas_page_unmap(addr);
RX_USED_ADD(page, dlen + cp->crc_size);
}
end_copy_pkt:
- if (cp->crc_size) {
- addr = NULL;
+ if (cp->crc_size)
crcaddr = skb->data + alloclen;
- }
+
skb_put(skb, alloclen);
}
@@ -2103,8 +2093,6 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
/* checksum includes FCS. strip it out. */
csum = csum_fold(csum_partial(crcaddr, cp->crc_size,
csum_unfold(csum)));
- if (addr)
- cas_page_unmap(addr);
}
skb->protocol = eth_type_trans(skb, cp->dev);
if (skb->protocol == htons(ETH_P_IP)) {
--
2.37.2
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