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authorSteve Hodgson <shodgson@solarflare.com>2010-06-01 13:33:17 +0200
committerDavid S. Miller <davem@davemloft.net>2010-06-02 11:21:08 +0200
commitf7d6f379db61233a1740cb2c6818b9c97531771f (patch)
treebf9af05c24d928bf6a66699d084912f68faddf05
parentsfc: Remove efx_rx_queue::add_lock (diff)
downloadlinux-f7d6f379db61233a1740cb2c6818b9c97531771f.tar.xz
linux-f7d6f379db61233a1740cb2c6818b9c97531771f.zip
sfc: Support only two rx buffers per page
- Pull the loop handling into efx_init_rx_buffers_(skb|page) - Remove rx_queue->buf_page, and associated clean up code - Remove unmap_addr, since unmap_addr is trivially calculable This will allow us to recycle discarded buffers directly from efx_rx_packet(), since will never be in the middle of splitting a page. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/sfc/net_driver.h10
-rw-r--r--drivers/net/sfc/rx.c228
2 files changed, 96 insertions, 142 deletions
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index 45398039dee6..59c8ecc39aee 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -222,7 +222,6 @@ struct efx_tx_queue {
* If both this and skb are %NULL, the buffer slot is currently free.
* @data: Pointer to ethernet header
* @len: Buffer length, in bytes.
- * @unmap_addr: DMA address to unmap
*/
struct efx_rx_buffer {
dma_addr_t dma_addr;
@@ -230,7 +229,6 @@ struct efx_rx_buffer {
struct page *page;
char *data;
unsigned int len;
- dma_addr_t unmap_addr;
};
/**
@@ -257,11 +255,6 @@ struct efx_rx_buffer {
* @alloc_page_count: RX allocation strategy counter.
* @alloc_skb_count: RX allocation strategy counter.
* @slow_fill: Timer used to defer efx_nic_generate_fill_event().
- * @buf_page: Page for next RX buffer.
- * We can use a single page for multiple RX buffers. This tracks
- * the remaining space in the allocation.
- * @buf_dma_addr: Page's DMA address.
- * @buf_data: Page's host address.
* @flushed: Use when handling queue flushing
*/
struct efx_rx_queue {
@@ -284,9 +277,6 @@ struct efx_rx_queue {
struct timer_list slow_fill;
unsigned int slow_fill_count;
- struct page *buf_page;
- dma_addr_t buf_dma_addr;
- char *buf_data;
enum efx_flush_state flushed;
};
diff --git a/drivers/net/sfc/rx.c b/drivers/net/sfc/rx.c
index bf1e55e7869e..615a1fcd6644 100644
--- a/drivers/net/sfc/rx.c
+++ b/drivers/net/sfc/rx.c
@@ -98,155 +98,132 @@ static inline unsigned int efx_rx_buf_size(struct efx_nic *efx)
return PAGE_SIZE << efx->rx_buffer_order;
}
-
/**
- * efx_init_rx_buffer_skb - create new RX buffer using skb-based allocation
+ * efx_init_rx_buffers_skb - create EFX_RX_BATCH skb-based RX buffers
*
* @rx_queue: Efx RX queue
- * @rx_buf: RX buffer structure to populate
*
- * This allocates memory for a new receive buffer, maps it for DMA,
- * and populates a struct efx_rx_buffer with the relevant
- * information. Return a negative error code or 0 on success.
+ * This allocates EFX_RX_BATCH skbs, maps them for DMA, and populates a
+ * struct efx_rx_buffer for each one. Return a negative error code or 0
+ * on success. May fail having only inserted fewer than EFX_RX_BATCH
+ * buffers.
*/
-static int efx_init_rx_buffer_skb(struct efx_rx_queue *rx_queue,
- struct efx_rx_buffer *rx_buf)
+static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue)
{
struct efx_nic *efx = rx_queue->efx;
struct net_device *net_dev = efx->net_dev;
+ struct efx_rx_buffer *rx_buf;
int skb_len = efx->rx_buffer_len;
+ unsigned index, count;
- rx_buf->skb = netdev_alloc_skb(net_dev, skb_len);
- if (unlikely(!rx_buf->skb))
- return -ENOMEM;
+ for (count = 0; count < EFX_RX_BATCH; ++count) {
+ index = rx_queue->added_count & EFX_RXQ_MASK;
+ rx_buf = efx_rx_buffer(rx_queue, index);
- /* Adjust the SKB for padding and checksum */
- skb_reserve(rx_buf->skb, NET_IP_ALIGN);
- rx_buf->len = skb_len - NET_IP_ALIGN;
- rx_buf->data = (char *)rx_buf->skb->data;
- rx_buf->skb->ip_summed = CHECKSUM_UNNECESSARY;
+ rx_buf->skb = netdev_alloc_skb(net_dev, skb_len);
+ if (unlikely(!rx_buf->skb))
+ return -ENOMEM;
+ rx_buf->page = NULL;
- rx_buf->dma_addr = pci_map_single(efx->pci_dev,
- rx_buf->data, rx_buf->len,
- PCI_DMA_FROMDEVICE);
+ /* Adjust the SKB for padding and checksum */
+ skb_reserve(rx_buf->skb, NET_IP_ALIGN);
+ rx_buf->len = skb_len - NET_IP_ALIGN;
+ rx_buf->data = (char *)rx_buf->skb->data;
+ rx_buf->skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+ rx_buf->dma_addr = pci_map_single(efx->pci_dev,
+ rx_buf->data, rx_buf->len,
+ PCI_DMA_FROMDEVICE);
+ if (unlikely(pci_dma_mapping_error(efx->pci_dev,
+ rx_buf->dma_addr))) {
+ dev_kfree_skb_any(rx_buf->skb);
+ rx_buf->skb = NULL;
+ return -EIO;
+ }
- if (unlikely(pci_dma_mapping_error(efx->pci_dev, rx_buf->dma_addr))) {
- dev_kfree_skb_any(rx_buf->skb);
- rx_buf->skb = NULL;
- return -EIO;
+ ++rx_queue->added_count;
+ ++rx_queue->alloc_skb_count;
}
return 0;
}
/**
- * efx_init_rx_buffer_page - create new RX buffer using page-based allocation
+ * efx_init_rx_buffers_page - create EFX_RX_BATCH page-based RX buffers
*
* @rx_queue: Efx RX queue
- * @rx_buf: RX buffer structure to populate
*
- * This allocates memory for a new receive buffer, maps it for DMA,
- * and populates a struct efx_rx_buffer with the relevant
- * information. Return a negative error code or 0 on success.
+ * This allocates memory for EFX_RX_BATCH receive buffers, maps them for DMA,
+ * and populates struct efx_rx_buffers for each one. Return a negative error
+ * code or 0 on success. If a single page can be split between two buffers,
+ * then the page will either be inserted fully, or not at at all.
*/
-static int efx_init_rx_buffer_page(struct efx_rx_queue *rx_queue,
- struct efx_rx_buffer *rx_buf)
+static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
{
struct efx_nic *efx = rx_queue->efx;
- int bytes, space, offset;
-
- bytes = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;
-
- /* If there is space left in the previously allocated page,
- * then use it. Otherwise allocate a new one */
- rx_buf->page = rx_queue->buf_page;
- if (rx_buf->page == NULL) {
- dma_addr_t dma_addr;
-
- rx_buf->page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC,
- efx->rx_buffer_order);
- if (unlikely(rx_buf->page == NULL))
+ struct efx_rx_buffer *rx_buf;
+ struct page *page;
+ char *page_addr;
+ dma_addr_t dma_addr;
+ unsigned index, count;
+
+ /* We can split a page between two buffers */
+ BUILD_BUG_ON(EFX_RX_BATCH & 1);
+
+ for (count = 0; count < EFX_RX_BATCH; ++count) {
+ page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC,
+ efx->rx_buffer_order);
+ if (unlikely(page == NULL))
return -ENOMEM;
-
- dma_addr = pci_map_page(efx->pci_dev, rx_buf->page,
- 0, efx_rx_buf_size(efx),
+ dma_addr = pci_map_page(efx->pci_dev, page, 0,
+ efx_rx_buf_size(efx),
PCI_DMA_FROMDEVICE);
-
if (unlikely(pci_dma_mapping_error(efx->pci_dev, dma_addr))) {
- __free_pages(rx_buf->page, efx->rx_buffer_order);
- rx_buf->page = NULL;
+ __free_pages(page, efx->rx_buffer_order);
return -EIO;
}
-
- rx_queue->buf_page = rx_buf->page;
- rx_queue->buf_dma_addr = dma_addr;
- rx_queue->buf_data = (page_address(rx_buf->page) +
- EFX_PAGE_IP_ALIGN);
- }
-
- rx_buf->len = bytes;
- rx_buf->data = rx_queue->buf_data;
- offset = efx_rx_buf_offset(rx_buf);
- rx_buf->dma_addr = rx_queue->buf_dma_addr + offset;
-
- /* Try to pack multiple buffers per page */
- if (efx->rx_buffer_order == 0) {
- /* The next buffer starts on the next 512 byte boundary */
- rx_queue->buf_data += ((bytes + 0x1ff) & ~0x1ff);
- offset += ((bytes + 0x1ff) & ~0x1ff);
-
- space = efx_rx_buf_size(efx) - offset;
- if (space >= bytes) {
- /* Refs dropped on kernel releasing each skb */
- get_page(rx_queue->buf_page);
- goto out;
+ EFX_BUG_ON_PARANOID(dma_addr & (PAGE_SIZE - 1));
+ page_addr = page_address(page) + EFX_PAGE_IP_ALIGN;
+ dma_addr += EFX_PAGE_IP_ALIGN;
+
+ split:
+ index = rx_queue->added_count & EFX_RXQ_MASK;
+ rx_buf = efx_rx_buffer(rx_queue, index);
+ rx_buf->dma_addr = dma_addr;
+ rx_buf->skb = NULL;
+ rx_buf->page = page;
+ rx_buf->data = page_addr;
+ rx_buf->len = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;
+ ++rx_queue->added_count;
+ ++rx_queue->alloc_page_count;
+
+ if ((~count & 1) && (efx->rx_buffer_len < (PAGE_SIZE >> 1))) {
+ /* Use the second half of the page */
+ get_page(page);
+ dma_addr += (PAGE_SIZE >> 1);
+ page_addr += (PAGE_SIZE >> 1);
+ ++count;
+ goto split;
}
}
- /* This is the final RX buffer for this page, so mark it for
- * unmapping */
- rx_queue->buf_page = NULL;
- rx_buf->unmap_addr = rx_queue->buf_dma_addr;
-
- out:
return 0;
}
-/* This allocates memory for a new receive buffer, maps it for DMA,
- * and populates a struct efx_rx_buffer with the relevant
- * information.
- */
-static int efx_init_rx_buffer(struct efx_rx_queue *rx_queue,
- struct efx_rx_buffer *new_rx_buf)
-{
- int rc = 0;
-
- if (rx_queue->channel->rx_alloc_push_pages) {
- new_rx_buf->skb = NULL;
- rc = efx_init_rx_buffer_page(rx_queue, new_rx_buf);
- rx_queue->alloc_page_count++;
- } else {
- new_rx_buf->page = NULL;
- rc = efx_init_rx_buffer_skb(rx_queue, new_rx_buf);
- rx_queue->alloc_skb_count++;
- }
-
- if (unlikely(rc < 0))
- EFX_LOG_RL(rx_queue->efx, "%s RXQ[%d] =%d\n", __func__,
- rx_queue->queue, rc);
- return rc;
-}
-
static void efx_unmap_rx_buffer(struct efx_nic *efx,
struct efx_rx_buffer *rx_buf)
{
if (rx_buf->page) {
EFX_BUG_ON_PARANOID(rx_buf->skb);
- if (rx_buf->unmap_addr) {
- pci_unmap_page(efx->pci_dev, rx_buf->unmap_addr,
+
+ /* Unmap the buffer if there's only one buffer per page(s),
+ * or this is the second half of a two buffer page. */
+ if (efx->rx_buffer_order != 0 ||
+ (efx_rx_buf_offset(rx_buf) & (PAGE_SIZE >> 1)) != 0) {
+ pci_unmap_page(efx->pci_dev,
+ rx_buf->dma_addr & ~(PAGE_SIZE - 1),
efx_rx_buf_size(efx),
PCI_DMA_FROMDEVICE);
- rx_buf->unmap_addr = 0;
}
} else if (likely(rx_buf->skb)) {
pci_unmap_single(efx->pci_dev, rx_buf->dma_addr,
@@ -286,9 +263,9 @@ static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue,
*/
void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
{
- struct efx_rx_buffer *rx_buf;
- unsigned fill_level, index;
- int i, space, rc = 0;
+ struct efx_channel *channel = rx_queue->channel;
+ unsigned fill_level;
+ int space, rc = 0;
/* Calculate current fill level, and exit if we don't need to fill */
fill_level = (rx_queue->added_count - rx_queue->removed_count);
@@ -309,21 +286,18 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
EFX_TRACE(rx_queue->efx, "RX queue %d fast-filling descriptor ring from"
" level %d to level %d using %s allocation\n",
rx_queue->queue, fill_level, rx_queue->fast_fill_limit,
- rx_queue->channel->rx_alloc_push_pages ? "page" : "skb");
+ channel->rx_alloc_push_pages ? "page" : "skb");
do {
- for (i = 0; i < EFX_RX_BATCH; ++i) {
- index = rx_queue->added_count & EFX_RXQ_MASK;
- rx_buf = efx_rx_buffer(rx_queue, index);
- rc = efx_init_rx_buffer(rx_queue, rx_buf);
- if (unlikely(rc)) {
- /* Ensure that we don't leave the rx queue
- * empty */
- if (rx_queue->added_count == rx_queue->removed_count)
- efx_schedule_slow_fill(rx_queue);
- goto out;
- }
- ++rx_queue->added_count;
+ if (channel->rx_alloc_push_pages)
+ rc = efx_init_rx_buffers_page(rx_queue);
+ else
+ rc = efx_init_rx_buffers_skb(rx_queue);
+ if (unlikely(rc)) {
+ /* Ensure that we don't leave the rx queue empty */
+ if (rx_queue->added_count == rx_queue->removed_count)
+ efx_schedule_slow_fill(rx_queue);
+ goto out;
}
} while ((space -= EFX_RX_BATCH) >= EFX_RX_BATCH);
@@ -638,16 +612,6 @@ void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
efx_fini_rx_buffer(rx_queue, rx_buf);
}
}
-
- /* For a page that is part-way through splitting into RX buffers */
- if (rx_queue->buf_page != NULL) {
- pci_unmap_page(rx_queue->efx->pci_dev, rx_queue->buf_dma_addr,
- efx_rx_buf_size(rx_queue->efx),
- PCI_DMA_FROMDEVICE);
- __free_pages(rx_queue->buf_page,
- rx_queue->efx->rx_buffer_order);
- rx_queue->buf_page = NULL;
- }
}
void efx_remove_rx_queue(struct efx_rx_queue *rx_queue)