[Intel-wired-lan] [PATCH net-next 1/2] e1000: Remove unnecessary use of kmap_atomic()

[Intel-wired-lan] [PATCH net-next 1/2] e1000: Remove unnecessary use of kmap_atomic()

[Anirudh Venkataramanan]

buffer_info->rxbuf.page accessed in e1000_clean_jumbo_rx_irq() is
allocated using GFP_ATOMIC. Pages allocated with GFP_ATOMIC can't come from
highmem and so there's no need to kmap() them. Just use page_address().

I don't have access to a 32-bit system so did some limited testing on
qemu (qemu-system-i386 -m 4096 -smp 4 -device e1000e) with a 32-bit
Debian 11.04 image.

Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Suggested-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
---
 drivers/net/ethernet/intel/e1000/e1000_main.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
index 23299fc..93e57b1 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -4229,8 +4229,6 @@ static bool e1000_clean_jumbo_rx_irq(struct e1000_adapter *adapter,
 				 */
 				p = buffer_info->rxbuf.page;
 				if (length <= copybreak) {
-					u8 *vaddr;
-
 					if (likely(!(netdev->features & NETIF_F_RXFCS)))
 						length -= 4;
 					skb = e1000_alloc_rx_skb(adapter,
@@ -4238,10 +4236,9 @@ static bool e1000_clean_jumbo_rx_irq(struct e1000_adapter *adapter,
 					if (!skb)
 						break;
 
-					vaddr = kmap_atomic(p);
-					memcpy(skb_tail_pointer(skb), vaddr,
-					       length);
-					kunmap_atomic(vaddr);
+					memcpy(skb_tail_pointer(skb),
+					       page_address(p), length);
+
 					/* re-use the page, so don't erase
 					 * buffer_info->rxbuf.page
 					 */
-- 
2.37.2

_______________________________________________
Intel-wired-lan mailing list
Intel-wired-lan@osuosl.org
https://lists.osuosl.org/mailman/listinfo/intel-wired-lan

[Intel-wired-lan] [PATCH net-next 2/2] e1000e: Remove unnecessary use of kmap_atomic()

[Anirudh Venkataramanan]

alloc_rx_buf() allocates ps_page->page and buffer_info->page 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().

I don't have access to a 32-bit system so did some limited testing on qemu
(qemu-system-i386 -m 4096 -smp 4 -device e1000e) with a 32-bit Debian 11.04
image.

Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Suggested-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
---
 drivers/net/ethernet/intel/e1000e/netdev.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 321f2a9..05a59e5 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -1393,21 +1393,14 @@ static bool e1000_clean_rx_irq_ps(struct e1000_ring *rx_ring, int *work_done,
 			 */
 			if (l1 && (l1 <= copybreak) &&
 			    ((length + l1) <= adapter->rx_ps_bsize0)) {
-				u8 *vaddr;
-
 				ps_page = &buffer_info->ps_pages[0];
 
-				/* there is no documentation about how to call
-				 * kmap_atomic, so we can't hold the mapping
-				 * very long
-				 */
 				dma_sync_single_for_cpu(&pdev->dev,
 							ps_page->dma,
 							PAGE_SIZE,
 							DMA_FROM_DEVICE);
-				vaddr = kmap_atomic(ps_page->page);
-				memcpy(skb_tail_pointer(skb), vaddr, l1);
-				kunmap_atomic(vaddr);
+				memcpy(skb_tail_pointer(skb),
+				       page_address(ps_page->page), l1);
 				dma_sync_single_for_device(&pdev->dev,
 							   ps_page->dma,
 							   PAGE_SIZE,
@@ -1607,11 +1600,9 @@ static bool e1000_clean_jumbo_rx_irq(struct e1000_ring *rx_ring, int *work_done,
 				 */
 				if (length <= copybreak &&
 				    skb_tailroom(skb) >= length) {
-					u8 *vaddr;
-					vaddr = kmap_atomic(buffer_info->page);
-					memcpy(skb_tail_pointer(skb), vaddr,
+					memcpy(skb_tail_pointer(skb),
+					       page_address(buffer_info->page),
 					       length);
-					kunmap_atomic(vaddr);
 					/* re-use the page, so don't erase
 					 * buffer_info->page
 					 */
-- 
2.37.2

_______________________________________________
Intel-wired-lan mailing list
Intel-wired-lan@osuosl.org
https://lists.osuosl.org/mailman/listinfo/intel-wired-lan