linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Ben Dooks <ben.dooks@codethink.co.uk>
To: netdev@vger.kernel.org
Cc: oneukum@suse.com, davem@davemloft.net, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org, steve.glendinning@shawell.net,
	linux-kernel@lists.codethink.co.uk,
	Ben Dooks <ben.dooks@codethink.co.uk>
Subject: [PATCH 2/4] usbnet: smsc95xx: simplify tx_fixup code
Date: Wed, 14 Nov 2018 11:50:20 +0000	[thread overview]
Message-ID: <20181114115022.9584-3-ben.dooks@codethink.co.uk> (raw)
In-Reply-To: <20181114115022.9584-1-ben.dooks@codethink.co.uk>

The smsc95xx_tx_fixup is doing multiple calls to skb_push() to
put an 8-byte command header onto the packet. It would be easier
to do one skb_push() and then copy the data in once the push is
done.

We also make the code smaller by using proper unaligned puts for
the header. This merges in the CPU to LE32 conversion as well and
makes the whole sequence easier to understand hopefully.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
---
Since v1:
- Add alignment changes using put_unaligned_le32()
---
 drivers/net/usb/smsc95xx.c | 28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index 401ec9feb495..50e97a159500 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -2006,6 +2006,7 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
 	bool csum = skb->ip_summed == CHECKSUM_PARTIAL;
 	int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM : SMSC95XX_TX_OVERHEAD;
 	u32 tx_cmd_a, tx_cmd_b;
+	void *ptr;
 
 	/* We do not advertise SG, so skbs should be already linearized */
 	BUG_ON(skb_shinfo(skb)->nr_frags);
@@ -2019,6 +2020,9 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
 		return NULL;
 	}
 
+	tx_cmd_b = (u32)skb->len;
+	tx_cmd_a = tx_cmd_b | TX_CMD_A_FIRST_SEG_ | TX_CMD_A_LAST_SEG_;
+
 	if (csum) {
 		if (skb->len <= 45) {
 			/* workaround - hardware tx checksum does not work
@@ -2032,24 +2036,18 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
 			csum = false;
 		} else {
 			u32 csum_preamble = smsc95xx_calc_csum_preamble(skb);
-			skb_push(skb, 4);
-			cpu_to_le32s(&csum_preamble);
-			memcpy(skb->data, &csum_preamble, 4);
+			ptr = skb_push(skb, 4);
+			put_unaligned_le32(csum_preamble, ptr);
+
+			tx_cmd_a += 4;
+			tx_cmd_b += 4;
+			tx_cmd_b |= TX_CMD_B_CSUM_ENABLE;
 		}
 	}
 
-	skb_push(skb, 4);
-	tx_cmd_b = (u32)(skb->len - 4);
-	if (csum)
-		tx_cmd_b |= TX_CMD_B_CSUM_ENABLE;
-	cpu_to_le32s(&tx_cmd_b);
-	memcpy(skb->data, &tx_cmd_b, 4);
-
-	skb_push(skb, 4);
-	tx_cmd_a = (u32)(skb->len - 8) | TX_CMD_A_FIRST_SEG_ |
-		TX_CMD_A_LAST_SEG_;
-	cpu_to_le32s(&tx_cmd_a);
-	memcpy(skb->data, &tx_cmd_a, 4);
+	ptr = skb_push(skb, 8);
+	put_unaligned_le32(tx_cmd_a, ptr);
+	put_unaligned_le32(tx_cmd_b, ptr+4);
 
 	return skb;
 }
-- 
2.19.1


  parent reply	other threads:[~2018-11-14 11:50 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-14 11:50 SMSC95xx driver updates (round 1) Ben Dooks
2018-11-14 11:50 ` [PATCH 1/4] usbnet: smsc95xx: fix rx packet alignment Ben Dooks
2018-11-14 11:50 ` Ben Dooks [this message]
2018-11-14 11:50 ` [PATCH 3/4] usbnet: smsc95xx: fix memcpy for accessing rx-data Ben Dooks
2018-11-14 11:50 ` [PATCH 4/4] usbnet: smsc95xx: check for csum being in last four bytes Ben Dooks
2018-11-14 15:59   ` Sergei Shtylyov
2018-11-14 11:58 ` SMSC95xx driver updates (round 1) Oliver Neukum
2018-11-15 18:06 ` Woojung.Huh
2018-11-16 10:49   ` Ben Dooks
2018-11-17  4:16 ` David Miller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20181114115022.9584-3-ben.dooks@codethink.co.uk \
    --to=ben.dooks@codethink.co.uk \
    --cc=davem@davemloft.net \
    --cc=linux-kernel@lists.codethink.co.uk \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=oneukum@suse.com \
    --cc=steve.glendinning@shawell.net \
    --subject='Re: [PATCH 2/4] usbnet: smsc95xx: simplify tx_fixup code' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
on how to clone and mirror all data and code used for this inbox