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path: root/drivers/net/xen-netback/netback.c
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2014-04-04xen-netback: Trivial format string fixZoltan Kiss
There is a "%" after pending_idx instead of ":". Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-03xen-netback: Grant copy the header instead of map and memcpyZoltan Kiss
An old inefficiency of the TX path that we are grant mapping the first slot, and then copy the header part to the linear area. Instead, doing a grant copy for that header straight on is more reasonable. Especially because there are ongoing efforts to make Xen avoiding TLB flush after unmap when the page were not touched in Dom0. In the original way the memcpy ruined that. The key changes: - the vif has a tx_copy_ops array again - xenvif_tx_build_gops sets up the grant copy operations - we don't have to figure out whether the header and first frag are on the same grant mapped page or not Note, we only grant copy PKT_PROT_LEN bytes from the first slot, the rest (if any) will be on the first frag, which is grant mapped. If the first slot is smaller than PKT_PROT_LEN, then we grant copy that, and later __pskb_pull_tail will pull more from the frags (if any) Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-03xen-netback: Rename map opsZoltan Kiss
Rename identifiers to state explicitly that they refer to map ops. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-01xen-netback: disable rogue vif in kthread contextWei Liu
When netback discovers frontend is sending malformed packet it will disables the interface which serves that frontend. However disabling a network interface involving taking a mutex which cannot be done in softirq context, so we need to defer this process to kthread context. This patch does the following: 1. introduce a flag to indicate the interface is disabled. 2. check that flag in TX path, don't do any work if it's true. 3. check that flag in RX path, turn off that interface if it's true. The reason to disable it in RX path is because RX uses kthread. After this change the behavior of netback is still consistent -- it won't do any TX work for a rogue frontend, and the interface will be eventually turned off. Also change a "continue" to "break" after xenvif_fatal_tx_err, as it doesn't make sense to continue processing packets if frontend is rogue. This is a fix for XSA-90. Reported-by: Török Edwin <edwin@etorok.net> Signed-off-by: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-31Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/xen-netback/netback.c A bug fix overlapped with changing how the netback SKB control block is implemented. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-29xen-netback: BUG_ON in xenvif_rx_action() not catching overflowPaul Durrant
The BUG_ON to catch ring overflow in xenvif_rx_action() makes the assumption that meta_slots_used == ring slots used. This is not necessarily the case for GSO packets, because the non-prefix GSO protocol consumes one more ring slot than meta-slot for the 'extra_info'. This patch changes the test to actually check ring slots. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-29xen-netback: worse-case estimate in xenvif_rx_action is underestimatingPaul Durrant
The worse-case estimate for skb ring slot usage in xenvif_rx_action() fails to take fragment page_offset into account. The page_offset does, however, affect the number of times the fragmentation code calls start_new_rx_buffer() (i.e. consume another slot) and the worse-case should assume that will always return true. This patch adds the page_offset into the DIV_ROUND_UP for each frag. Unfortunately some frontends aggressively limit the number of requests they post into the shared ring so to avoid an estimate that is 'too' pessimal it is capped at MAX_SKB_FRAGS. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-29xen-netback: remove pointless clause from if statementPaul Durrant
This patch removes a test in start_new_rx_buffer() that checks whether a copy operation is less than MAX_BUFFER_OFFSET in length, since MAX_BUFFER_OFFSET is defined to be PAGE_SIZE and the only caller of start_new_rx_buffer() already limits copy operations to PAGE_SIZE or less. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Sander Eikelenboom <linux@eikelenboom.it> Reported-By: Sander Eikelenboom <linux@eikelenboom.it> Tested-By: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-26xen-netback: Functional follow-up patch for grant mapping seriesZoltan Kiss
Ian made some late comments about the grant mapping series, I incorporated the functional outcomes into this patch: - use callback_param macro to shorten access to pending_tx_info in xenvif_fill_frags() and xenvif_tx_submit() - print an error message in xenvif_idx_unmap() before panic Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-26xen-netback: Non-functional follow-up patch for grant mapping seriesZoltan Kiss
Ian made some late comments about the grant mapping series, I incorporated the non-functional outcomes into this patch: - typo fixes in a comment of xenvif_free(), and add another one there as well - typo fix for comment of rx_drain_timeout_msecs - remove stale comment before calling xenvif_grant_handle_reset() Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-26xen-netback: Stop using xenvif_tx_pending_slots_availableZoltan Kiss
Since the early days TX stops if there isn't enough free pending slots to consume a maximum sized (slot-wise) packet. Probably the reason for that is to avoid the case when we don't have enough free pending slot in the ring to finish the packet. But if we make sure that the pending ring has the same size as the shared ring, that shouldn't really happen. The frontend can only post packets which fit the to the free space of the shared ring. If it doesn't, the frontend has to stop, as it can only increase the req_prod when the whole packet fits onto the ring. This patch avoid using this checking, makes sure the 2 ring has the same size, and remove a checking from the callback. As now we don't stop the NAPI instance on this condition, we don't have to wake it up if we free pending slots up. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-25xen-netback: Proper printf format for ptrdiff_t is 't'.David S. Miller
This fixes: drivers/net/xen-netback/netback.c: In function ‘xenvif_tx_dealloc_action’: drivers/net/xen-netback/netback.c:1573:8: warning: format ‘%x’ expects argument of type ‘unsigned int’, but argument 3 has type ‘long int’ [-Wformat=] Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-25Revert "xen-netback: Aggregate TX unmap operations"Zoltan Kiss
This reverts commit e9275f5e2df1b2098a8cc405d87b88b9affd73e6. This commit is the last in the netback grant mapping series, and it tries to do more aggressive aggreagtion of unmap operations. However practical use showed almost no positive effect, whilst with certain frontends it causes significant performance regression. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-14Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/usb/r8152.c drivers/net/xen-netback/netback.c Both the r8152 and netback conflicts were simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-10Xen-netback: Fix issue caused by using gso_type wronglyAnnie Li
Current netback uses gso_type to check whether the skb contains gso offload, and this is wrong. Gso_size is the right one to check gso existence, and gso_type is only used to check gso type. Some skbs contains nonzero gso_type and zero gso_size, current netback would treat these skbs as gso and create wrong response for this. This also causes ssh failure to domu from other server. V2: use skb_is_gso function as Paul Durrant suggested Signed-off-by: Annie Li <annie.li@oracle.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-07xen-netback: Aggregate TX unmap operationsZoltan Kiss
Unmapping causes TLB flushing, therefore we should make it in the largest possible batches. However we shouldn't starve the guest for too long. So if the guest has space for at least two big packets and we don't have at least a quarter ring to unmap, delay it for at most 1 milisec. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-07xen-netback: Timeout packets in RX pathZoltan Kiss
A malicious or buggy guest can leave its queue filled indefinitely, in which case qdisc start to queue packets for that VIF. If those packets came from an another guest, it can block its slots and prevent shutdown. To avoid that, we make sure the queue is drained in every 10 seconds. The QDisc queue in worst case takes 3 round to flush usually. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-07xen-netback: Handle guests with too many fragsZoltan Kiss
Xen network protocol had implicit dependency on MAX_SKB_FRAGS. Netback has to handle guests sending up to XEN_NETBK_LEGACY_SLOTS_MAX slots. To achieve that: - create a new skb - map the leftover slots to its frags (no linear buffer here!) - chain it to the previous through skb_shinfo(skb)->frag_list - map them - copy and coalesce the frags into a brand new one and send it to the stack - unmap the 2 old skb's pages It's also introduces new stat counters, which help determine how often the guest sends a packet with more than MAX_SKB_FRAGS frags. NOTE: if bisect brought you here, you should apply the series up until "xen-netback: Timeout packets in RX path", otherwise malicious guests can block other guests by not releasing their sent packets. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-07xen-netback: Add stat counters for zerocopyZoltan Kiss
These counters help determine how often the buffers had to be copied. Also they help find out if packets are leaked, as if "sent != success + fail", there are probably packets never freed up properly. NOTE: if bisect brought you here, you should apply the series up until "xen-netback: Timeout packets in RX path", otherwise Windows guests can't work properly and malicious guests can block other guests by not releasing their sent packets. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-07xen-netback: Remove old TX grant copy definitons and fix indentationsZoltan Kiss
These became obsolete with grant mapping. I've left intentionally the indentations in this way, to improve readability of previous patches. NOTE: if bisect brought you here, you should apply the series up until "xen-netback: Timeout packets in RX path", otherwise Windows guests can't work properly and malicious guests can block other guests by not releasing their sent packets. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-07xen-netback: Introduce TX grant mappingZoltan Kiss
This patch introduces grant mapping on netback TX path. It replaces grant copy operations, ditching grant copy coalescing along the way. Another solution for copy coalescing is introduced in "xen-netback: Handle guests with too many frags", older guests and Windows can broke before that patch applies. There is a callback (xenvif_zerocopy_callback) from core stack to release the slots back to the guests when kfree_skb or skb_orphan_frags called. It feeds a separate dealloc thread, as scheduling NAPI instance from there is inefficient, therefore we can't do dealloc from the instance. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-07xen-netback: Handle foreign mapped pages on the guest RX pathZoltan Kiss
RX path need to know if the SKB fragments are stored on pages from another domain. Logically this patch should be after introducing the grant mapping itself, as it makes sense only after that. But to keep bisectability, I moved it here. It shouldn't change any functionality here. xenvif_zerocopy_callback and ubuf_to_vif are just stubs here, they will be introduced properly later on. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-07xen-netback: Minor refactoring of netback codeZoltan Kiss
This patch contains a few bits of refactoring before introducing the grant mapping changes: - introducing xenvif_tx_pending_slots_available(), as this is used several times, and will be used more often - rename the thread to vifX.Y-guest-rx, to signify it does RX work from the guest point of view Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-07xen-netback: Use skb->cb for pending_idxZoltan Kiss
Storing the pending_idx at the first byte of the linear buffer never looked good, skb->cb is a more proper place for this. It also prevents the header to be directly grant copied there, and we don't have the pending_idx after we copied the header here, so it's time to change it. It also introduces helpers for the RX side Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-05xen-netback: Fix Rx stall due to race conditionZoltan Kiss
The recent patch to fix receive side flow control (11b57f90257c1d6a91cee720151b69e0c2020cf6: xen-netback: stop vif thread spinning if frontend is unresponsive) solved the spinning thread problem, however caused an another one. The receive side can stall, if: - [THREAD] xenvif_rx_action sets rx_queue_stopped to true - [INTERRUPT] interrupt happens, and sets rx_event to true - [THREAD] then xenvif_kthread sets rx_event to false - [THREAD] rx_work_todo doesn't return true anymore Also, if interrupt sent but there is still no room in the ring, it take quite a long time until xenvif_rx_action realize it. This patch ditch that two variable, and rework rx_work_todo. If the thread finds it can't fit more skb's into the ring, it saves the last slot estimation into rx_last_skb_slots, otherwise it's kept as 0. Then rx_work_todo will check if: - there is something to send to the ring (like before) - there is space for the topmost packet in the queue I think that's more natural and optimal thing to test than two bool which are set somewhere else. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-14xen-netback: use new skb_checksum_setup functionPaul Durrant
Use skb_checksum_setup to set up partial checksum offsets rather then a private implementation. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-09xen-netback: stop vif thread spinning if frontend is unresponsivePaul Durrant
The recent patch to improve guest receive side flow control (ca2f09f2) had a slight flaw in the wait condition for the vif thread in that any remaining skbs in the guest receive side netback internal queue would prevent the thread from sleeping. An unresponsive frontend can lead to a permanently non-empty internal queue and thus the thread will spin. In this case the thread should really sleep until the frontend becomes responsive again. This patch adds an extra flag to the vif which is set if the shared ring is full and cleared when skbs are drained into the shared ring. Thus, if the thread runs, finds the shared ring full and can make no progress the flag remains set. If the flag remains set then the thread will sleep, regardless of a non-empty queue, until the next event from the frontend. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-06Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_pf.c net/ipv6/ip6_tunnel.c net/ipv6/ip6_vti.c ipv6 tunnel statistic bug fixes conflicting with consolidation into generic sw per-cpu net stats. qlogic conflict between queue counting bug fix and the addition of multiple MAC address support. Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-29xen-netback: fix guest-receive-side array sizesPaul Durrant
The sizes chosen for the metadata and grant_copy_op arrays on the guest receive size are wrong; - The meta array is needlessly twice the ring size, when we only ever consume a single array element per RX ring slot - The grant_copy_op array is way too small. It's sized based on a bogus assumption: that at most two copy ops will be used per ring slot. This may have been true at some point in the past but it's clear from looking at start_new_rx_buffer() that a new ring slot is only consumed if a frag would overflow the current slot (plus some other conditions) so the actual limit is MAX_SKB_FRAGS grant_copy_ops per ring slot. This patch fixes those two sizing issues and, because grant_copy_ops grows so much, it pulls it out into a separate chunk of vmalloc()ed memory. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-19xen-netback: add gso_segs calculationPaul Durrant
netback already has code which parses IPv4 and v6 headers to set up checksum offsets and these are always applied to GSO packets being sent from frontends. It's therefore suboptimal that GSOs are being marked SKB_GSO_DODGY to defer the gso_segs calculation when netback already has all necessary information to hand to do the calculation. This patch adds that calculation. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-19xen-netback: fix some error return codeWei Yongjun
'err' is overwrited to 0 after maybe_pull_tail() call, so the error code was not set if skb_partial_csum_set() call failed. Fix to return error -EPROTO from those error handling case instead of 0. Fixes: d52eb0d46f36 ('xen-netback: make sure skb linear area covers checksum field') Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/ethernet/intel/i40e/i40e_main.c drivers/net/macvtap.c Both minor merge hassles, simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-17xen-netback: fix fragments error handling in checksum_setup_ip()Wei Yongjun
Fix to return -EPROTO error if fragments detected in checksum_setup_ip(). Fixes: 1431fb31ecba ('xen-netback: fix fragment detection in checksum setup') Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-12xen-netback: fix gso_prefix checkPaul Durrant
There is a mistake in checking the gso_prefix mask when passing large packets to a guest. The wrong shift is applied to the bit - the raw skb gso type is used rather then the translated one. This leads to large packets being handed to the guest without the GSO metadata. This patch fixes the check. The mistake manifested as errors whilst running Microsoft HCK large packet offload tests between a pair of Windows 8 VMs. I have verified this patch fixes those errors. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-12xen-netback: napi: don't prematurely request a tx eventPaul Durrant
This patch changes the RING_FINAL_CHECK_FOR_REQUESTS in xenvif_build_tx_gops to a check for RING_HAS_UNCONSUMED_REQUESTS as the former call has the side effect of advancing the ring event pointer and therefore inviting another interrupt from the frontend before the napi poll has actually finished, thereby defeating the point of napi. The event pointer is updated by RING_FINAL_CHECK_FOR_REQUESTS in xenvif_poll, the napi poll function, if the work done is less than the budget i.e. when actually transitioning back to interrupt mode. Reported-by: Malcolm Crossley <malcolm.crossley@citrix.com> Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-12xen-netback: napi: fix abuse of budgetPaul Durrant
netback seems to be somewhat confused about the napi budget parameter. The parameter is supposed to limit the number of skbs processed in each poll, but netback has this confused with grant operations. This patch fixes that, properly limiting the work done in each poll. Note that this limit makes sure we do not process any more data from the shared ring than we intend to pass back from the poll. This is important to prevent tx_queue potentially growing without bound. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-11xen-netback: make sure skb linear area covers checksum fieldPaul Durrant
skb_partial_csum_set requires that the linear area of the skb covers the checksum field. The checksum setup code in netback was only doing that pullup in the case when the pseudo header checksum was being recalculated though. This patch makes that pullup unconditional. (I pullup the whole transport header just for simplicity; the requirement is only for the check field but in the case of UDP this is the last field in the header and in the case of TCP it's the last but one). The lack of pullup manifested as failures running Microsoft HCK network tests on a pair of Windows 8 VMs and it has been verified that this patch fixes the problem. Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-09xen-netback: improve guest-receive-side flow controlPaul Durrant
The way that flow control works without this patch is that, in start_xmit() the code uses xenvif_count_skb_slots() to predict how many slots xenvif_gop_skb() will consume and then adds this to a 'req_cons_peek' counter which it then uses to determine if the shared ring has that amount of space available by checking whether 'req_prod' has passed that value. If the ring doesn't have space the tx queue is stopped. xenvif_gop_skb() will then consume slots and update 'req_cons' and issue responses, updating 'rsp_prod' as it goes. The frontend will consume those responses and post new requests, by updating req_prod. So, req_prod chases req_cons which chases rsp_prod, and can never exceed that value. Thus if xenvif_count_skb_slots() ever returns a number of slots greater than xenvif_gop_skb() uses, req_cons_peek will get to a value that req_prod cannot possibly achieve (since it's limited by the 'real' req_cons) and, if this happens enough times, req_cons_peek gets more than a ring size ahead of req_cons and the tx queue then remains stopped forever waiting for an unachievable amount of space to become available in the ring. Having two routines trying to calculate the same value is always going to be fragile, so this patch does away with that. All we essentially need to do is make sure that we have 'enough stuff' on our internal queue without letting it build up uncontrollably. So start_xmit() makes a cheap optimistic check of how much space is needed for an skb and only turns the queue off if that is unachievable. net_rx_action() is the place where we could do with an accurate predicition but, since that has proven tricky to calculate, a cheap worse-case (but not too bad) estimate is all we really need since the only thing we *must* prevent is xenvif_gop_skb() consuming more slots than are available. Without this patch I can trivially stall netback permanently by just doing a large guest to guest file copy between two Windows Server 2008R2 VMs on a single host. Patch tested with frontends in: - Windows Server 2008R2 - CentOS 6.0 - Debian Squeeze - Debian Wheezy - SLES11 Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Annie Li <annie.li@oracle.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-05xen-netback: fix fragment detection in checksum setupPaul Durrant
The code to detect fragments in checksum_setup() was missing for IPv4 and too eager for IPv6. (It transpires that Windows seems to send IPv6 packets with a fragment header even if they are not a fragment - i.e. offset is zero, and M bit is not set). This patch also incorporates a fix to callers of maybe_pull_tail() where skb->network_header was being erroneously added to the length argument. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> cc: David Miller <davem@davemloft.net> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-28xen-netback: include definition of csum_ipv6_magicAndy Whitcroft
We are now using csum_ipv6_magic, include the appropriate header. Avoids the following error: drivers/net/xen-netback/netback.c:1313:4: error: implicit declaration of function 'csum_ipv6_magic' [-Werror=implicit-function-declaration] tcph->check = ~csum_ipv6_magic(&ipv6h->saddr, Signed-off-by: Andy Whitcroft <apw@canonical.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/ethernet/emulex/benet/be.h drivers/net/netconsole.c net/bridge/br_private.h Three mostly trivial conflicts. The net/bridge/br_private.h conflict was a function signature (argument addition) change overlapping with the extern removals from Joe Perches. In drivers/net/netconsole.c we had one change adjusting a printk message whilst another changed "printk(KERN_INFO" into "pr_info(". Lastly, the emulex change was a new inline function addition overlapping with Joe Perches's extern removals. Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-29xen-netback: use jiffies_64 value to calculate credit timeoutWei Liu
time_after_eq() only works if the delta is < MAX_ULONG/2. For a 32bit Dom0, if netfront sends packets at a very low rate, the time between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2 and the test for timer_after_eq() will be incorrect. Credit will not be replenished and the guest may become unable to send packets (e.g., if prior to the long gap, all credit was exhausted). Use jiffies_64 variant to mitigate this problem for 32bit Dom0. Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Wei Liu <wei.liu2@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Jason Luan <jianhai.luan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-17xen-netback: enable IPv6 TCP GSO to the guestPaul Durrant
This patch adds code to handle SKB_GSO_TCPV6 skbs and construct appropriate extra or prefix segments to pass the large packet to the frontend. New xenstore flags, feature-gso-tcpv6 and feature-gso-tcpv6-prefix, are sampled to determine if the frontend is capable of handling such packets. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-17xen-netback: handle IPv6 TCP GSO packets from the guestPaul Durrant
This patch adds a xenstore feature flag, festure-gso-tcpv6, to advertise that netback can handle IPv6 TCP GSO packets. It creates SKB_GSO_TCPV6 skbs if the frontend passes an extra segment with the new type XEN_NETIF_GSO_TYPE_TCPV6 added to netif.h. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-17xen-netback: add support for IPv6 checksum offload from guestPaul Durrant
For performance of VM to VM traffic on a single host it is better to avoid calculation of TCP/UDP checksum in the sending frontend. To allow this this patch adds the code necessary to set up partial checksum for IPv6 packets and xenstore flag feature-ipv6-csum-offload to advertise that fact to frontends. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-08Revert "xen-netback: improve ring effeciency for guest RX"Wei Liu
This reverts commit 4f0581d25827d5e864bcf07b05d73d0d12a20a5c. The named changeset is causing problem. Let's aim to make this part less fragile before trying to improve things. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Annie Li <annie.li@oracle.com> Cc: Matt Wilson <msw@amazon.com> Cc: Xi Xiong <xixiong@amazon.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Paul Durrant <paul.durrant@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-09-30xen-netback: improve ring effeciency for guest RXWei Liu
There was a bug that netback routines netbk/xenvif_skb_count_slots and netbk/xenvif_gop_frag_copy disagreed with each other, which caused netback to push wrong number of responses to netfront, which caused netfront to eventually crash. The bug was fixed in 6e43fc04a ("xen-netback: count number required slots for an skb more carefully"). Commit 6e43fc04a focused on backport-ability. The drawback with the existing packing scheme is that the ring is not used effeciently, as stated in 6e43fc04a. skb->data like: | 1111|222222222222|3333 | is arranged as: |1111 |222222222222|3333 | If we can do this: |111122222222|22223333 | That would save one ring slot, which improves ring effeciency. This patch effectively reverts 6e43fc04a. That patch made count_slots agree with gop_frag_copy, while this patch goes the other way around -- make gop_frag_copy agree with count_slots. The end result is that they still agree with each other, and the ring is now arranged like: |111122222222|22223333 | The patch that improves packing was first posted by Xi Xong and Matt Wilson. I only rebase it on top of net-next and rewrite commit message, so I retain all their SoBs. For more infomation about the original bug please refer to email listed below and commit message of 6e43fc04a. Original patch: http://lists.xen.org/archives/html/xen-devel/2013-07/msg00760.html Signed-off-by: Xi Xiong <xixiong@amazon.com> Reviewed-by: Matt Wilson <msw@amazon.com> [ msw: minor code cleanups, rewrote commit message, adjusted code to count RX slots instead of meta structures ] Signed-off-by: Matt Wilson <msw@amazon.com> Cc: Annie Li <annie.li@oracle.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> [ liuw: rebased on top of net-next tree, rewrote commit message, coding style cleanup. ] Signed-off-by: Wei Liu <wei.liu2@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Acked-by: Ian Campbell <Ian.Campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-09-12xen-netback: count number required slots for an skb more carefullyDavid Vrabel
When a VM is providing an iSCSI target and the LUN is used by the backend domain, the generated skbs for direct I/O writes to the disk have large, multi-page skb->data but no frags. With some lengths and starting offsets, xen_netbk_count_skb_slots() would be one short because the simple calculation of DIV_ROUND_UP(skb_headlen(), PAGE_SIZE) was not accounting for the decisions made by start_new_rx_buffer() which does not guarantee responses are fully packed. For example, a skb with length < 2 pages but which spans 3 pages would be counted as requiring 2 slots but would actually use 3 slots. skb->data: | 1111|222222222222|3333 | Fully packed, this would need 2 slots: |111122222222|22223333 | But because the 2nd page wholy fits into a slot it is not split across slots and goes into a slot of its own: |1111 |222222222222|3333 | Miscounting the number of slots means netback may push more responses than the number of available requests. This will cause the frontend to get very confused and report "Too many frags/slots". The frontend never recovers and will eventually BUG. Fix this by counting the number of required slots more carefully. In xen_netbk_count_skb_slots(), more closely follow the algorithm used by xen_netbk_gop_skb() by introducing xen_netbk_count_frag_slots() which is the dry-run equivalent of netbk_gop_frag_copy(). Signed-off-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-29xen-netback: rename functionsWei Liu
As we move to 1:1 model and melt xen_netbk and xenvif together, it would be better to use single prefix for all functions in xen-netback. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-29xen-netback: switch to NAPI + kthread 1:1 modelWei Liu
This patch implements 1:1 model netback. NAPI and kthread are utilized to do the weight-lifting job: - NAPI is used for guest side TX (host side RX) - kthread is used for guest side RX (host side TX) Xenvif and xen_netbk are made into one structure to reduce code size. This model provides better scheduling fairness among vifs. It is also prerequisite for implementing multiqueue for Xen netback. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>