diff options
author | Karsten Keil <kkeil@linux-pingi.de> | 2012-05-15 23:51:05 (GMT) |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2012-05-16 19:23:28 (GMT) |
commit | 7206e659f689558b41aa058c3040b081cb281d03 (patch) | |
tree | 2be5bdef5a0bbb9c5763b8c1b1e6fe04b7184cc5 /drivers/isdn/mISDN/hwchannel.c | |
parent | 37952cfa3afdfa5cec39d9d76e80bc3a0e6a910c (diff) | |
download | linux-7206e659f689558b41aa058c3040b081cb281d03.tar.xz |
mISDN: Reduce RX buffer allocation for transparent data
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>
Diffstat (limited to 'drivers/isdn/mISDN/hwchannel.c')
-rw-r--r-- | drivers/isdn/mISDN/hwchannel.c | 75 |
1 files changed, 63 insertions, 12 deletions
diff --git a/drivers/isdn/mISDN/hwchannel.c b/drivers/isdn/mISDN/hwchannel.c index 5c5ab47..3c2145d 100644 --- a/drivers/isdn/mISDN/hwchannel.c +++ b/drivers/isdn/mISDN/hwchannel.c @@ -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); |