/* * Copyright (c) 2007 The University of Aberdeen, Scotland, UK * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand. * Copyright (c) 2005-7 Ian McDonald * Copyright (c) 2005 Arnaldo Carvalho de Melo * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ #include #include "tfrc.h" static struct kmem_cache *tfrc_lh_slab __read_mostly; /* Loss Interval weights from [RFC 3448, 5.4], scaled by 10 */ static const int tfrc_lh_weights[NINTERVAL] = { 10, 10, 10, 10, 8, 6, 4, 2 }; /* implements LIFO semantics on the array */ static inline u8 LIH_INDEX(const u8 ctr) { return LIH_SIZE - 1 - (ctr % LIH_SIZE); } /* the `counter' index always points at the next entry to be populated */ static inline struct tfrc_loss_interval *tfrc_lh_peek(struct tfrc_loss_hist *lh) { return lh->counter ? lh->ring[LIH_INDEX(lh->counter - 1)] : NULL; } /* given i with 0 <= i <= k, return I_i as per the rfc3448bis notation */ static inline u32 tfrc_lh_get_interval(struct tfrc_loss_hist *lh, const u8 i) { BUG_ON(i >= lh->counter); return lh->ring[LIH_INDEX(lh->counter - i - 1)]->li_length; } /* * On-demand allocation and de-allocation of entries */ static struct tfrc_loss_interval *tfrc_lh_demand_next(struct tfrc_loss_hist *lh) { if (lh->ring[LIH_INDEX(lh->counter)] == NULL) lh->ring[LIH_INDEX(lh->counter)] = kmem_cache_alloc(tfrc_lh_slab, GFP_ATOMIC); return lh->ring[LIH_INDEX(lh->counter)]; } void tfrc_lh_cleanup(struct tfrc_loss_hist *lh) { if (!tfrc_lh_is_initialised(lh)) return; for (lh->counter = 0; lh->counter < LIH_SIZE; lh->counter++) if (lh->ring[LIH_INDEX(lh->counter)] != NULL) { kmem_cache_free(tfrc_lh_slab, lh->ring[LIH_INDEX(lh->counter)]); lh->ring[LIH_INDEX(lh->counter)] = NULL; } } static void tfrc_lh_calc_i_mean(struct tfrc_loss_hist *lh) { u32 i_i, i_tot0 = 0, i_tot1 = 0, w_tot = 0; int i, k = tfrc_lh_length(lh) - 1; /* k is as in rfc3448bis, 5.4 */ if (k <= 0) return; for (i = 0; i <= k; i++) { i_i = tfrc_lh_get_interval(lh, i); if (i < k) { i_tot0 += i_i * tfrc_lh_weights[i]; w_tot += tfrc_lh_weights[i]; } if (i > 0) i_tot1 += i_i * tfrc_lh_weights[i-1]; } lh->i_mean = max(i_tot0, i_tot1) / w_tot; } /** * tfrc_lh_update_i_mean - Update the `open' loss interval I_0 * For recomputing p: returns `true' if p > p_prev <=> 1/p < 1/p_prev */ u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb) { struct tfrc_loss_interval *cur = tfrc_lh_peek(lh); u32 old_i_mean = lh->i_mean; s64 len; if (cur == NULL) /* not initialised */ return 0; len = dccp_delta_seqno(cur->li_seqno, DCCP_SKB_CB(skb)->dccpd_seq) + 1; if (len - (s64)cur->li_length <= 0) /* duplicate or reordered */ return 0; if (SUB16(dccp_hdr(skb)->dccph_ccval, cur->li_ccval) > 4) /* * Implements RFC 4342, 10.2: * If a packet S (skb) exists whose seqno comes `after' the one * starting the current loss interval (cur) and if the modulo-16 * distance from C(cur) to C(S) is greater than 4, consider all * subsequent packets as belonging to a new loss interval. This * test is necessary since CCVal may wrap between intervals. */ cur->li_is_closed = 1; if (tfrc_lh_length(lh) == 1) /* due to RFC 3448, 6.3.1 */ return 0; cur->li_length = len; tfrc_lh_calc_i_mean(lh); return lh->i_mean < old_i_mean; } /* Determine if `new_loss' does begin a new loss interval [RFC 4342, 10.2] */ static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur, struct tfrc_rx_hist_entry *new_loss) { return dccp_delta_seqno(cur->li_seqno, new_loss->tfrchrx_seqno) > 0 && (cur->li_is_closed || SUB16(new_loss->tfrchrx_ccval, cur->li_ccval) > 4); } /** * tfrc_lh_interval_add - Insert new record into the Loss Interval database * @lh: Loss Interval database * @rh: Receive history containing a fresh loss event * @calc_first_li: Caller-dependent routine to compute length of first interval * @sk: Used by @calc_first_li in caller-specific way (subtyping) * * Updates I_mean and returns 1 if a new interval has in fact been added to @lh. */ int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh, u32 (*calc_first_li)(struct sock *), struct sock *sk) { struct tfrc_loss_interval *cur = tfrc_lh_peek(lh), *new; if (cur != NULL && !tfrc_lh_is_new_loss(cur, tfrc_rx_hist_loss_prev(rh))) return 0; new = tfrc_lh_demand_next(lh); if (unlikely(new == NULL)) { DCCP_CRIT("Cannot allocate/add loss record."); return 0; } new->li_seqno = tfrc_rx_hist_loss_prev(rh)->tfrchrx_seqno; new->li_ccval = tfrc_rx_hist_loss_prev(rh)->tfrchrx_ccval; new->li_is_closed = 0; if (++lh->counter == 1) lh->i_mean = new->li_length = (*calc_first_li)(sk); else { cur->li_length = dccp_delta_seqno(cur->li_seqno, new->li_seqno); new->li_length = dccp_delta_seqno(new->li_seqno, tfrc_rx_hist_last_rcv(rh)->tfrchrx_seqno) + 1; if (lh->counter > (2*LIH_SIZE)) lh->counter -= LIH_SIZE; tfrc_lh_calc_i_mean(lh); } return 1; } int __init tfrc_li_init(void) { tfrc_lh_slab = kmem_cache_create("tfrc_li_hist", sizeof(struct tfrc_loss_interval), 0, SLAB_HWCACHE_ALIGN, NULL); return tfrc_lh_slab == NULL ? -ENOBUFS : 0; } void tfrc_li_exit(void) { if (tfrc_lh_slab != NULL) { kmem_cache_destroy(tfrc_lh_slab); tfrc_lh_slab = NULL; } } ff/net/llc/llc_proc.c?id=030305d69fc6963c16003f50d7e8d74b02d0a143&id2=4d191b1b63c209e37bf27938ef365244d3c41084'>diff)
PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies
In a struct pcie_link_state, link->root points to the pcie_link_state of the root of the PCIe hierarchy. For the topmost link, this points to itself (link->root = link). For others, we copy the pointer from the parent (link->root = link->parent->root). Previously we recognized that Root Ports originated PCIe hierarchies, but we treated PCI/PCI-X to PCIe Bridges as being in the middle of the hierarchy, and when we tried to copy the pointer from link->parent->root, there was no parent, and we dereferenced a NULL pointer: BUG: unable to handle kernel NULL pointer dereference at 0000000000000090 IP: [<ffffffff9e424350>] pcie_aspm_init_link_state+0x170/0x820 Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just like Root Ports do, so link->root for these devices should also point to itself. Fixes: 51ebfc92b72b ("PCI: Enumerate switches below PCI-to-PCIe bridges") Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411 Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181 Tested-by: lists@ssl-mail.com Tested-by: Jayachandran C. <jnair@caviumnetworks.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v4.2+
Diffstat (limited to 'net/llc/llc_proc.c')