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95162d6524
I noticed excess calls to skb_copy_expand() or memmove() in asix driver. This driver needs to push 4 bytes in front of frame (packet_len) and maybe add 4 bytes after the end (if padlen is 4) So it should set needed_headroom & needed_tailroom to avoid copies. But its not enough, because many packets are cloned before entering asix_tx_fixup() and this driver use skb_cloned() as a lazy way to check if it can push and put additional bytes in frame. Avoid skb_copy_expand() expensive call, using following rules : - We are allowed to push 4 bytes in headroom if skb_header_cloned() is false (and if we have 4 bytes of headroom) - We are allowed to put 4 bytes at tail if skb_cloned() is false (and if we have 4 bytes of tailroom) TCP packets for example are cloned, but skb_header_release() was called in tcp stack, allowing us to use headroom for our needs. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Allan Chou <allan@asix.com.tw> Cc: Trond Wuellner <trond@chromium.org> Cc: Grant Grundler <grundler@chromium.org> Cc: Paul Stewart <pstew@chromium.org> Cc: Ming Lei <tom.leiming@gmail.com> Tested-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| asix.c | ||
| catc.c | ||
| cdc_eem.c | ||
| cdc_ether.c | ||
| cdc_ncm.c | ||
| cdc_subset.c | ||
| cdc-phonet.c | ||
| cx82310_eth.c | ||
| dm9601.c | ||
| gl620a.c | ||
| hso.c | ||
| int51x1.c | ||
| ipheth.c | ||
| kalmia.c | ||
| kaweth.c | ||
| Kconfig | ||
| lg-vl600.c | ||
| Makefile | ||
| mcs7830.c | ||
| net1080.c | ||
| pegasus.c | ||
| pegasus.h | ||
| plusb.c | ||
| qmi_wwan.c | ||
| rndis_host.c | ||
| rtl8150.c | ||
| sierra_net.c | ||
| smsc75xx.c | ||
| smsc75xx.h | ||
| smsc95xx.c | ||
| smsc95xx.h | ||
| usbnet.c | ||
| zaurus.c | ||