From e29d4363174949a7a4e46f670993d7ff43342c1c Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Sun, 15 Nov 2009 22:23:47 -0800 Subject: [PATCH] Revert "isdn: isdn_ppp: Use SKB list facilities instead of home-grown implementation." This reverts commit 38783e671399b5405f1fd177d602c400a9577ae6. It causes kernel bugzilla #14594 Signed-off-by: David S. Miller --- drivers/isdn/i4l/isdn_ppp.c | 348 +++++++++++++++++------------------- include/linux/isdn_ppp.h | 2 +- 2 files changed, 162 insertions(+), 188 deletions(-) diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c index 2d14b64202a3..642d5aaf53ce 100644 --- a/drivers/isdn/i4l/isdn_ppp.c +++ b/drivers/isdn/i4l/isdn_ppp.c @@ -1535,10 +1535,8 @@ static int isdn_ppp_mp_bundle_array_init(void) int sz = ISDN_MAX_CHANNELS*sizeof(ippp_bundle); if( (isdn_ppp_bundle_arr = kzalloc(sz, GFP_KERNEL)) == NULL ) return -ENOMEM; - for (i = 0; i < ISDN_MAX_CHANNELS; i++) { + for( i = 0; i < ISDN_MAX_CHANNELS; i++ ) spin_lock_init(&isdn_ppp_bundle_arr[i].lock); - skb_queue_head_init(&isdn_ppp_bundle_arr[i].frags); - } return 0; } @@ -1571,7 +1569,7 @@ static int isdn_ppp_mp_init( isdn_net_local * lp, ippp_bundle * add_to ) if ((lp->netdev->pb = isdn_ppp_mp_bundle_alloc()) == NULL) return -ENOMEM; lp->next = lp->last = lp; /* nobody else in a queue */ - skb_queue_head_init(&lp->netdev->pb->frags); + lp->netdev->pb->frags = NULL; lp->netdev->pb->frames = 0; lp->netdev->pb->seq = UINT_MAX; } @@ -1583,29 +1581,28 @@ static int isdn_ppp_mp_init( isdn_net_local * lp, ippp_bundle * add_to ) static u32 isdn_ppp_mp_get_seq( int short_seq, struct sk_buff * skb, u32 last_seq ); -static void isdn_ppp_mp_discard(ippp_bundle *mp, struct sk_buff *from, - struct sk_buff *to); -static void isdn_ppp_mp_reassembly(isdn_net_dev *net_dev, isdn_net_local *lp, - struct sk_buff *from, struct sk_buff *to, - u32 lastseq); -static void isdn_ppp_mp_free_skb(ippp_bundle *mp, struct sk_buff *skb); +static struct sk_buff * isdn_ppp_mp_discard( ippp_bundle * mp, + struct sk_buff * from, struct sk_buff * to ); +static void isdn_ppp_mp_reassembly( isdn_net_dev * net_dev, isdn_net_local * lp, + struct sk_buff * from, struct sk_buff * to ); +static void isdn_ppp_mp_free_skb( ippp_bundle * mp, struct sk_buff * skb ); static void isdn_ppp_mp_print_recv_pkt( int slot, struct sk_buff * skb ); static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp, - struct sk_buff *skb) + struct sk_buff *skb) { - struct sk_buff *newfrag, *frag, *start, *nextf; - u32 newseq, minseq, thisseq; - isdn_mppp_stats *stats; struct ippp_struct *is; + isdn_net_local * lpq; + ippp_bundle * mp; + isdn_mppp_stats * stats; + struct sk_buff * newfrag, * frag, * start, *nextf; + u32 newseq, minseq, thisseq; unsigned long flags; - isdn_net_local *lpq; - ippp_bundle *mp; int slot; spin_lock_irqsave(&net_dev->pb->lock, flags); - mp = net_dev->pb; - stats = &mp->stats; + mp = net_dev->pb; + stats = &mp->stats; slot = lp->ppp_slot; if (slot < 0 || slot >= ISDN_MAX_CHANNELS) { printk(KERN_ERR "%s: lp->ppp_slot(%d)\n", @@ -1616,19 +1613,20 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp, return; } is = ippp_table[slot]; - if (++mp->frames > stats->max_queue_len) + if( ++mp->frames > stats->max_queue_len ) stats->max_queue_len = mp->frames; - + if (is->debug & 0x8) isdn_ppp_mp_print_recv_pkt(lp->ppp_slot, skb); - newseq = isdn_ppp_mp_get_seq(is->mpppcfg & SC_IN_SHORT_SEQ, - skb, is->last_link_seqno); + newseq = isdn_ppp_mp_get_seq(is->mpppcfg & SC_IN_SHORT_SEQ, + skb, is->last_link_seqno); + /* if this packet seq # is less than last already processed one, * toss it right away, but check for sequence start case first */ - if (mp->seq > MP_LONGSEQ_MAX && (newseq & MP_LONGSEQ_MAXBIT)) { + if( mp->seq > MP_LONGSEQ_MAX && (newseq & MP_LONGSEQ_MAXBIT) ) { mp->seq = newseq; /* the first packet: required for * rfc1990 non-compliant clients -- * prevents constant packet toss */ @@ -1638,7 +1636,7 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp, spin_unlock_irqrestore(&mp->lock, flags); return; } - + /* find the minimum received sequence number over all links */ is->last_link_seqno = minseq = newseq; for (lpq = net_dev->queue;;) { @@ -1659,31 +1657,22 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp, * packets */ newfrag = skb; - /* Insert new fragment into the proper sequence slot. */ - skb_queue_walk(&mp->frags, frag) { - if (MP_SEQ(frag) == newseq) { - isdn_ppp_mp_free_skb(mp, newfrag); - newfrag = NULL; - break; - } - if (MP_LT(newseq, MP_SEQ(frag))) { - __skb_queue_before(&mp->frags, frag, newfrag); - newfrag = NULL; - break; - } - } - if (newfrag) - __skb_queue_tail(&mp->frags, newfrag); + /* if this new fragment is before the first one, then enqueue it now. */ + if ((frag = mp->frags) == NULL || MP_LT(newseq, MP_SEQ(frag))) { + newfrag->next = frag; + mp->frags = frag = newfrag; + newfrag = NULL; + } - frag = skb_peek(&mp->frags); - start = ((MP_FLAGS(frag) & MP_BEGIN_FRAG) && - (MP_SEQ(frag) == mp->seq)) ? frag : NULL; - if (!start) - goto check_overflow; + start = MP_FLAGS(frag) & MP_BEGIN_FRAG && + MP_SEQ(frag) == mp->seq ? frag : NULL; - /* main fragment traversing loop + /* + * main fragment traversing loop * * try to accomplish several tasks: + * - insert new fragment into the proper sequence slot (once that's done + * newfrag will be set to NULL) * - reassemble any complete fragment sequence (non-null 'start' * indicates there is a continguous sequence present) * - discard any incomplete sequences that are below minseq -- due @@ -1692,46 +1681,71 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp, * come to complete such sequence and it should be discarded * * loop completes when we accomplished the following tasks: + * - new fragment is inserted in the proper sequence ('newfrag' is + * set to NULL) * - we hit a gap in the sequence, so no reassembly/processing is * possible ('start' would be set to NULL) * * algorithm for this code is derived from code in the book * 'PPP Design And Debugging' by James Carlson (Addison-Wesley) */ - skb_queue_walk_safe(&mp->frags, frag, nextf) { - thisseq = MP_SEQ(frag); + while (start != NULL || newfrag != NULL) { - /* check for misplaced start */ - if (start != frag && (MP_FLAGS(frag) & MP_BEGIN_FRAG)) { - printk(KERN_WARNING"isdn_mppp(seq %d): new " - "BEGIN flag with no prior END", thisseq); - stats->seqerrs++; - stats->frame_drops++; - isdn_ppp_mp_discard(mp, start, frag); - start = frag; - } else if (MP_LE(thisseq, minseq)) { - if (MP_FLAGS(frag) & MP_BEGIN_FRAG) + thisseq = MP_SEQ(frag); + nextf = frag->next; + + /* drop any duplicate fragments */ + if (newfrag != NULL && thisseq == newseq) { + isdn_ppp_mp_free_skb(mp, newfrag); + newfrag = NULL; + } + + /* insert new fragment before next element if possible. */ + if (newfrag != NULL && (nextf == NULL || + MP_LT(newseq, MP_SEQ(nextf)))) { + newfrag->next = nextf; + frag->next = nextf = newfrag; + newfrag = NULL; + } + + if (start != NULL) { + /* check for misplaced start */ + if (start != frag && (MP_FLAGS(frag) & MP_BEGIN_FRAG)) { + printk(KERN_WARNING"isdn_mppp(seq %d): new " + "BEGIN flag with no prior END", thisseq); + stats->seqerrs++; + stats->frame_drops++; + start = isdn_ppp_mp_discard(mp, start,frag); + nextf = frag->next; + } + } else if (MP_LE(thisseq, minseq)) { + if (MP_FLAGS(frag) & MP_BEGIN_FRAG) start = frag; - else { + else { if (MP_FLAGS(frag) & MP_END_FRAG) - stats->frame_drops++; - __skb_unlink(skb, &mp->frags); + stats->frame_drops++; + if( mp->frags == frag ) + mp->frags = nextf; isdn_ppp_mp_free_skb(mp, frag); + frag = nextf; continue; - } + } } - - /* if we have end fragment, then we have full reassembly - * sequence -- reassemble and process packet now + + /* if start is non-null and we have end fragment, then + * we have full reassembly sequence -- reassemble + * and process packet now */ - if (MP_FLAGS(frag) & MP_END_FRAG) { - minseq = mp->seq = (thisseq+1) & MP_LONGSEQ_MASK; - /* Reassemble the packet then dispatch it */ - isdn_ppp_mp_reassembly(net_dev, lp, start, frag, thisseq); + if (start != NULL && (MP_FLAGS(frag) & MP_END_FRAG)) { + minseq = mp->seq = (thisseq+1) & MP_LONGSEQ_MASK; + /* Reassemble the packet then dispatch it */ + isdn_ppp_mp_reassembly(net_dev, lp, start, nextf); + + start = NULL; + frag = NULL; - start = NULL; - frag = NULL; - } + mp->frags = nextf; + } /* check if need to update start pointer: if we just * reassembled the packet and sequence is contiguous @@ -1742,25 +1756,26 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp, * below low watermark and set start to the next frag or * clear start ptr. */ - if (nextf != (struct sk_buff *)&mp->frags && + if (nextf != NULL && ((thisseq+1) & MP_LONGSEQ_MASK) == MP_SEQ(nextf)) { - /* if we just reassembled and the next one is here, - * then start another reassembly. - */ - if (frag == NULL) { + /* if we just reassembled and the next one is here, + * then start another reassembly. */ + + if (frag == NULL) { if (MP_FLAGS(nextf) & MP_BEGIN_FRAG) - start = nextf; - else { - printk(KERN_WARNING"isdn_mppp(seq %d):" - " END flag with no following " - "BEGIN", thisseq); + start = nextf; + else + { + printk(KERN_WARNING"isdn_mppp(seq %d):" + " END flag with no following " + "BEGIN", thisseq); stats->seqerrs++; } } - } else { - if (nextf != (struct sk_buff *)&mp->frags && - frag != NULL && - MP_LT(thisseq, minseq)) { + + } else { + if ( nextf != NULL && frag != NULL && + MP_LT(thisseq, minseq)) { /* we've got a break in the sequence * and we not at the end yet * and we did not just reassembled @@ -1769,39 +1784,41 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp, * discard all the frames below low watermark * and start over */ stats->frame_drops++; - isdn_ppp_mp_discard(mp, start, nextf); + mp->frags = isdn_ppp_mp_discard(mp,start,nextf); } /* break in the sequence, no reassembly */ - start = NULL; - } - if (!start) - break; - } - -check_overflow: + start = NULL; + } + + frag = nextf; + } /* while -- main loop */ + + if (mp->frags == NULL) + mp->frags = frag; + /* rather straighforward way to deal with (not very) possible - * queue overflow - */ + * queue overflow */ if (mp->frames > MP_MAX_QUEUE_LEN) { stats->overflows++; - skb_queue_walk_safe(&mp->frags, frag, nextf) { - if (mp->frames <= MP_MAX_QUEUE_LEN) - break; - __skb_unlink(frag, &mp->frags); - isdn_ppp_mp_free_skb(mp, frag); + while (mp->frames > MP_MAX_QUEUE_LEN) { + frag = mp->frags->next; + isdn_ppp_mp_free_skb(mp, mp->frags); + mp->frags = frag; } } spin_unlock_irqrestore(&mp->lock, flags); } -static void isdn_ppp_mp_cleanup(isdn_net_local *lp) +static void isdn_ppp_mp_cleanup( isdn_net_local * lp ) { - struct sk_buff *skb, *tmp; - - skb_queue_walk_safe(&lp->netdev->pb->frags, skb, tmp) { - __skb_unlink(skb, &lp->netdev->pb->frags); - isdn_ppp_mp_free_skb(lp->netdev->pb, skb); + struct sk_buff * frag = lp->netdev->pb->frags; + struct sk_buff * nextfrag; + while( frag ) { + nextfrag = frag->next; + isdn_ppp_mp_free_skb(lp->netdev->pb, frag); + frag = nextfrag; } + lp->netdev->pb->frags = NULL; } static u32 isdn_ppp_mp_get_seq( int short_seq, @@ -1838,115 +1855,72 @@ static u32 isdn_ppp_mp_get_seq( int short_seq, return seq; } -static void isdn_ppp_mp_discard(ippp_bundle *mp, struct sk_buff *from, - struct sk_buff *to) +struct sk_buff * isdn_ppp_mp_discard( ippp_bundle * mp, + struct sk_buff * from, struct sk_buff * to ) { - if (from) { - struct sk_buff *skb, *tmp; - int freeing = 0; - - skb_queue_walk_safe(&mp->frags, skb, tmp) { - if (skb == to) - break; - if (skb == from) - freeing = 1; - if (!freeing) - continue; - __skb_unlink(skb, &mp->frags); - isdn_ppp_mp_free_skb(mp, skb); + if( from ) + while (from != to) { + struct sk_buff * next = from->next; + isdn_ppp_mp_free_skb(mp, from); + from = next; } - } + return from; } -static unsigned int calc_tot_len(struct sk_buff_head *queue, - struct sk_buff *from, struct sk_buff *to) +void isdn_ppp_mp_reassembly( isdn_net_dev * net_dev, isdn_net_local * lp, + struct sk_buff * from, struct sk_buff * to ) { - unsigned int tot_len = 0; - struct sk_buff *skb; - int found_start = 0; - - skb_queue_walk(queue, skb) { - if (skb == from) - found_start = 1; - if (!found_start) - continue; - tot_len += skb->len - MP_HEADER_LEN; - if (skb == to) - break; - } - return tot_len; -} - -/* Reassemble packet using fragments in the reassembly queue from - * 'from' until 'to', inclusive. - */ -static void isdn_ppp_mp_reassembly(isdn_net_dev *net_dev, isdn_net_local *lp, - struct sk_buff *from, struct sk_buff *to, - u32 lastseq) -{ - ippp_bundle *mp = net_dev->pb; - unsigned int tot_len; - struct sk_buff *skb; + ippp_bundle * mp = net_dev->pb; int proto; + struct sk_buff * skb; + unsigned int tot_len; if (lp->ppp_slot < 0 || lp->ppp_slot >= ISDN_MAX_CHANNELS) { printk(KERN_ERR "%s: lp->ppp_slot(%d) out of range\n", __func__, lp->ppp_slot); return; } - - tot_len = calc_tot_len(&mp->frags, from, to); - - if (MP_FLAGS(from) == (MP_BEGIN_FRAG | MP_END_FRAG)) { - if (ippp_table[lp->ppp_slot]->debug & 0x40) + if( MP_FLAGS(from) == (MP_BEGIN_FRAG | MP_END_FRAG) ) { + if( ippp_table[lp->ppp_slot]->debug & 0x40 ) printk(KERN_DEBUG "isdn_mppp: reassembly: frame %d, " - "len %d\n", MP_SEQ(from), from->len); + "len %d\n", MP_SEQ(from), from->len ); skb = from; skb_pull(skb, MP_HEADER_LEN); - __skb_unlink(skb, &mp->frags); mp->frames--; } else { - struct sk_buff *walk, *tmp; - int found_start = 0; + struct sk_buff * frag; + int n; - if (ippp_table[lp->ppp_slot]->debug & 0x40) + for(tot_len=n=0, frag=from; frag != to; frag=frag->next, n++) + tot_len += frag->len - MP_HEADER_LEN; + + if( ippp_table[lp->ppp_slot]->debug & 0x40 ) printk(KERN_DEBUG"isdn_mppp: reassembling frames %d " - "to %d, len %d\n", MP_SEQ(from), lastseq, - tot_len); - - skb = dev_alloc_skb(tot_len); - if (!skb) + "to %d, len %d\n", MP_SEQ(from), + (MP_SEQ(from)+n-1) & MP_LONGSEQ_MASK, tot_len ); + if( (skb = dev_alloc_skb(tot_len)) == NULL ) { printk(KERN_ERR "isdn_mppp: cannot allocate sk buff " - "of size %d\n", tot_len); + "of size %d\n", tot_len); + isdn_ppp_mp_discard(mp, from, to); + return; + } - found_start = 0; - skb_queue_walk_safe(&mp->frags, walk, tmp) { - if (walk == from) - found_start = 1; - if (!found_start) - continue; + while( from != to ) { + unsigned int len = from->len - MP_HEADER_LEN; - if (skb) { - unsigned int len = walk->len - MP_HEADER_LEN; - skb_copy_from_linear_data_offset(walk, MP_HEADER_LEN, - skb_put(skb, len), - len); - } - __skb_unlink(walk, &mp->frags); - isdn_ppp_mp_free_skb(mp, walk); - - if (walk == to) - break; + skb_copy_from_linear_data_offset(from, MP_HEADER_LEN, + skb_put(skb,len), + len); + frag = from->next; + isdn_ppp_mp_free_skb(mp, from); + from = frag; } } - if (!skb) - return; - proto = isdn_ppp_strip_proto(skb); isdn_ppp_push_higher(net_dev, lp, skb, proto); } -static void isdn_ppp_mp_free_skb(ippp_bundle *mp, struct sk_buff *skb) +static void isdn_ppp_mp_free_skb(ippp_bundle * mp, struct sk_buff * skb) { dev_kfree_skb(skb); mp->frames--; diff --git a/include/linux/isdn_ppp.h b/include/linux/isdn_ppp.h index 4c218ee7587a..8687a7dc0632 100644 --- a/include/linux/isdn_ppp.h +++ b/include/linux/isdn_ppp.h @@ -157,7 +157,7 @@ typedef struct { typedef struct { int mp_mrru; /* unused */ - struct sk_buff_head frags; /* fragments sl list */ + struct sk_buff * frags; /* fragments sl list -- use skb->next */ long frames; /* number of frames in the frame list */ unsigned int seq; /* last processed packet seq #: any packets * with smaller seq # will be dropped