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mISDN: Reduce RX buffer allocation for transparent data

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We did allways allocate maxsize buffers, but for transparent data we know
the actual size.
Use a common function to calculate size and detect overflows.

Signed-off-by: Karsten Keil <kkeil@linux-pingi.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Karsten Keil
2012-05-15 23:51:05 +00:00
committed by David S. Miller
parent 37952cfa3a
commit 7206e659f6
10 changed files with 193 additions and 195 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/isdn/mISDN/hwchannel.c
+63 -12
View File
@@ -201,20 +201,30 @@ recv_Bchannel(struct bchannel *bch, unsigned int id)
{
struct mISDNhead *hh;
hh = mISDN_HEAD_P(bch->rx_skb);
hh->prim = PH_DATA_IND;
hh->id = id;
if (bch->rcount >= 64) {
printk(KERN_WARNING "B-channel %p receive queue overflow, "
"flushing!\n", bch);
skb_queue_purge(&bch->rqueue);
bch->rcount = 0;
/* if allocation did fail upper functions still may call us */
if (unlikely(!bch->rx_skb))
return;
if (unlikely(!bch->rx_skb->len)) {
/* we have no data to send - this may happen after recovery
* from overflow or too small allocation.
* We need to free the buffer here */
dev_kfree_skb(bch->rx_skb);
bch->rx_skb = NULL;
} else {
hh = mISDN_HEAD_P(bch->rx_skb);
hh->prim = PH_DATA_IND;
hh->id = id;
if (bch->rcount >= 64) {
printk(KERN_WARNING
"B%d receive queue overflow - flushing!\n",
bch->nr);
skb_queue_purge(&bch->rqueue);
}
bch->rcount++;
skb_queue_tail(&bch->rqueue, bch->rx_skb);
bch->rx_skb = NULL;
schedule_event(bch, FLG_RECVQUEUE);
}
bch->rcount++;
skb_queue_tail(&bch->rqueue, bch->rx_skb);
bch->rx_skb = NULL;
schedule_event(bch, FLG_RECVQUEUE);
}
EXPORT_SYMBOL(recv_Bchannel);
@@ -399,3 +409,44 @@ bchannel_senddata(struct bchannel *ch, struct sk_buff *skb)
}
}
EXPORT_SYMBOL(bchannel_senddata);
/* The function allocates a new receive skb on demand with a size for the
* requirements of the current protocol. It returns the tailroom of the
* receive skb or an error.
*/
int
bchannel_get_rxbuf(struct bchannel *bch, int reqlen)
{
int len;
if (bch->rx_skb) {
len = skb_tailroom(bch->rx_skb);
if (len < reqlen) {
pr_warning("B%d no space for %d (only %d) bytes\n",
bch->nr, reqlen, len);
if (test_bit(FLG_TRANSPARENT, &bch->Flags)) {
/* send what we have now and try a new buffer */
recv_Bchannel(bch, 0);
} else {
/* on HDLC we have to drop too big frames */
return -EMSGSIZE;
}
} else {
return len;
}
}
if (unlikely(reqlen > bch->maxlen))
return -EMSGSIZE;
if (test_bit(FLG_TRANSPARENT, &bch->Flags))
len = reqlen;
else /* with HDLC we do not know the length yet */
len = bch->maxlen;
bch->rx_skb = mI_alloc_skb(len, GFP_ATOMIC);
if (!bch->rx_skb) {
pr_warning("B%d receive no memory for %d bytes\n",
bch->nr, len);
len = -ENOMEM;
}
return len;
}
EXPORT_SYMBOL(bchannel_get_rxbuf);