diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-12-23 16:23:23 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-12-23 16:23:23 +0100 |
commit | 1ccedb7cdba6886939dd8b4c8f965a826f696e56 (patch) | |
tree | 0f5fc519a68faca5318c296315c9b6c502907056 /net/can/af_can.c | |
parent | a98f8fd24fb24fcb9a359553e64dd6aac5cf4279 (diff) | |
parent | 929096fe9ff1f4b3645cf3919527ab47e8d5e17c (diff) |
Merge commit 'v2.6.28-rc9' into x86/apic
Diffstat (limited to 'net/can/af_can.c')
-rw-r--r-- | net/can/af_can.c | 68 |
1 files changed, 52 insertions, 16 deletions
diff --git a/net/can/af_can.c b/net/can/af_can.c index 7d4d2b3c137..3dadb338add 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -319,23 +319,52 @@ static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) return n ? d : NULL; } +/** + * find_rcv_list - determine optimal filterlist inside device filter struct + * @can_id: pointer to CAN identifier of a given can_filter + * @mask: pointer to CAN mask of a given can_filter + * @d: pointer to the device filter struct + * + * Description: + * Returns the optimal filterlist to reduce the filter handling in the + * receive path. This function is called by service functions that need + * to register or unregister a can_filter in the filter lists. + * + * A filter matches in general, when + * + * <received_can_id> & mask == can_id & mask + * + * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe + * relevant bits for the filter. + * + * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can + * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames + * there is a special filterlist and a special rx path filter handling. + * + * Return: + * Pointer to optimal filterlist for the given can_id/mask pair. + * Constistency checked mask. + * Reduced can_id to have a preprocessed filter compare value. + */ static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, struct dev_rcv_lists *d) { canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ - /* filter error frames */ + /* filter for error frames in extra filterlist */ if (*mask & CAN_ERR_FLAG) { - /* clear CAN_ERR_FLAG in list entry */ + /* clear CAN_ERR_FLAG in filter entry */ *mask &= CAN_ERR_MASK; return &d->rx[RX_ERR]; } - /* ensure valid values in can_mask */ - if (*mask & CAN_EFF_FLAG) - *mask &= (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG); - else - *mask &= (CAN_SFF_MASK | CAN_RTR_FLAG); + /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ + +#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) + + /* ensure valid values in can_mask for 'SFF only' frame filtering */ + if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) + *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); /* reduce condition testing at receive time */ *can_id &= *mask; @@ -348,15 +377,19 @@ static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, if (!(*mask)) return &d->rx[RX_ALL]; - /* use extra filterset for the subscription of exactly *ONE* can_id */ - if (*can_id & CAN_EFF_FLAG) { - if (*mask == (CAN_EFF_MASK | CAN_EFF_FLAG)) { - /* RFC: a use-case for hash-tables in the future? */ - return &d->rx[RX_EFF]; + /* extra filterlists for the subscription of a single non-RTR can_id */ + if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) + && !(*can_id & CAN_RTR_FLAG)) { + + if (*can_id & CAN_EFF_FLAG) { + if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) { + /* RFC: a future use-case for hash-tables? */ + return &d->rx[RX_EFF]; + } + } else { + if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) + return &d->rx_sff[*can_id]; } - } else { - if (*mask == CAN_SFF_MASK) - return &d->rx_sff[*can_id]; } /* default: filter via can_id/can_mask */ @@ -589,7 +622,10 @@ static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) } } - /* check CAN_ID specific entries */ + /* check filterlists for single non-RTR can_ids */ + if (can_id & CAN_RTR_FLAG) + return matches; + if (can_id & CAN_EFF_FLAG) { hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) { if (r->can_id == can_id) { |