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* vhost: Move VHOST_NET_FEATURES to net.cAsias He2013-05-061-0/+6
| | | | | | | | vhost.h should not depend on device specific marcos like VHOST_NET_F_VIRTIO_NET_HDR and VIRTIO_NET_F_MRG_RXBUF. Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost-net: Free ubuf when vhost_dev_set_owner failsAsias He2013-05-061-6/+32
| | | | | Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost: fix error handling in RESET_OWNER ioctlMichael S. Tsirkin2013-05-011-1/+7
| | | | | | | | | | RESET_OWNER ioctl would leave the fd in a bad state if memory allocation failed: device is stopped but owner is not reset. Make state changes after allocating memory, such that a failed ioctl has no effect. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost: move per-vq net specific fields out to netMichael S. Tsirkin2013-05-011-16/+27
| | | | | | | This will remove the need for vhost scsi to pull in virtio-net.h. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost: move vhost-net zerocopy fields to net.cAsias He2013-05-011-23/+141
| | | | | | | | On top of 'vhost: Allow device specific fields per vq', we can move device specific fields to device virt queue from vhost virt queue. Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost: Allow device specific fields per vqAsias He2013-05-011-23/+41
| | | | | | | | | | | This is useful for any device who wants device specific fields per vq. For example, tcm_vhost wants a per vq field to track requests which are in flight on the vq. Also, on top of this we can add patches to move things like ubufs from vhost.h out to net.c. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost_net: remove tx polling stateJason Wang2013-04-111-68/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After commit 2b8b328b61c799957a456a5a8dab8cc7dea68575 (vhost_net: handle polling errors when setting backend), we in fact track the polling state through poll->wqh, so there's no need to duplicate the work with an extra vhost_net_polling_state. So this patch removes this and make the code simpler. This patch also removes the all tx starting/stopping code in tx path according to Michael's suggestion. Netperf test shows almost the same result in stream test, but gets improvements on TCP_RR tests (both zerocopy or copy) especially on low load cases. Tested between multiqueue kvm guest and external host with two direct connected 82599s. zerocopy disabled: sessions|transaction rates|normalize| before/after/+improvements 1 | 9510.24/11727.29/+23.3% | 693.54/887.68/+28.0% | 25| 192931.50/241729.87/+25.3% | 2376.80/2771.70/+16.6% | 50| 277634.64/291905.76/+5% | 3118.36/3230.11/+3.6% | zerocopy enabled: sessions|transaction rates|normalize| before/after/+improvements 1 | 7318.33/11929.76/+63.0% | 521.86/843.30/+61.6% | 25| 167264.88/242422.15/+44.9% | 2181.60/2788.16/+27.8% | 50| 272181.02/294347.04/+8.1% | 3071.56/3257.85/+6.1% | Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* vhost/net: fix heads usage of ubuf_infoMichael S. Tsirkin2013-03-171-1/+2
| | | | | | | | | | | | ubuf info allocator uses guest controlled head as an index, so a malicious guest could put the same head entry in the ring twice, and we will get two callbacks on the same value. To fix use upend_idx which is guaranteed to be unique. Reported-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Cc: stable@kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
* vhost_net: handle polling errors when setting backendJason Wang2013-01-291-9/+18
| | | | | | | | | | | | | | | | | | | | | | | Currently, the polling errors were ignored, which can lead following issues: - vhost remove itself unconditionally from waitqueue when stopping the poll, this may crash the kernel since the previous attempt of starting may fail to add itself to the waitqueue - userspace may think the backend were successfully set even when the polling failed. Solve this by: - check poll->wqh before trying to remove from waitqueue - report polling errors in vhost_poll_start(), tx_poll_start(), the return value will be checked and returned when userspace want to set the backend After this fix, there still could be a polling failure after backend is set, it will addressed by the next patch. Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* vhost_net: correct error handling in vhost_net_set_backend()Jason Wang2013-01-291-5/+11
| | | | | | | | | Currently, when vhost_init_used() fails the sock refcnt and ubufs were leaked. Correct this by calling vhost_init_used() before assign ubufs and restore the oldsock when it fails. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* vhost-net: enable zerocopy tx by defaultMichael S. Tsirkin2012-12-061-2/+3
| | | | | | | | | | | | | | Zero copy TX has been around for a while now. We seem to be down to eliminating theoretical bugs and performance tuning at this point: it's probably time to enable it by default so that most users get the benefit. Keep the flag around meanwhile so users can experiment with disabling this if they experience regressions. I expect that we will remove it in the future. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost-net: skip head management if no outstandingMichael S. Tsirkin2012-12-061-4/+7
| | | | | | | | | | | | For short packets zerocopy mode adds overhead of managing heads which isn't necessary: we could simly update used ring directly same as with zerocopy disabled. Things seem to run a bit faster if we detect and bypass head management when zcopy isn't used. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost-net: flush outstanding DMAs on memory changeMichael S. Tsirkin2012-12-061-9/+19
| | | | | | | | | | When memory map changes, we need to flush outstanding DMAs as they might in theory reference old memory addresses. To do this simply stop initiating new DMAs and wait for ubufs ref count to drop to 0. Afterwards reset the count back to 1. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost: avoid backend flush on vring opsMichael S. Tsirkin2012-12-061-2/+5
| | | | | | | | | | | vring changes already do a flush internally where appropriate, so we do not need a second flush. It's currently not very expensive but a follow-up patch makes flush more heavy-weight, so remove the extra flush here to avoid regressing performance if call or kick fds are changed on data path. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost-net: initialize zcopy packet countersMichael S. Tsirkin2012-12-031-0/+3
| | | | | | | | | | | These packet counters are used to drive the zercopy selection heuristic so nothing too bad happens if they are off a bit - and they are also reset once in a while. But it's cleaner to clear them when backend is set so that we start in a known state. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2012-11-101-1/+2
|\ | | | | | | | | | | | | | | | | | | | | Conflicts: drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c Minor conflict between the BCM_CNIC define removal in net-next and a bug fix added to net. Based upon a conflict resolution patch posted by Stephen Rothwell. Signed-off-by: David S. Miller <davem@davemloft.net>
| * vhost: fix mergeable bufs on BE hostsMichael S. Tsirkin2012-10-241-1/+2
| | | | | | | | | | | | | | | | | | | | We copy head count to a 16 bit field, this works by chance on LE but on BE guest gets 0. Fix it up. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Alexander Graf <agraf@suse.de> Cc: stable@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
* | vhost-net: reduce vq polling on tx zerocopyMichael S. Tsirkin2012-11-021-2/+12
| | | | | | | | | | | | | | | | | | It seems that to avoid deadlocks it is enough to poll vq before we are going to use the last buffer. This is faster than c70aa540c7a9f67add11ad3161096fb95233aa2e. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | vhost-net: select tx zero copy dynamicallyMichael S. Tsirkin2012-11-021-8/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Even when vhost-net is in zero-copy transmit mode, net core might still decide to copy the skb later which is somewhat slower than a copy in user context: data copy overhead is added to the cost of page pin/unpin. The result is that enabling tx zero copy option leads to higher CPU utilization for guest to guest and guest to host traffic. To fix this, suppress zero copy tx after a given number of packets triggered late data copy. Re-enable periodically to detect workload changes. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | vhost: move -net specific code outMichael S. Tsirkin2012-11-021-0/+45
| | | | | | | | | | | | | | | | Zerocopy handling code is vhost-net specific. Move it from vhost.c/vhost.h out to net.c Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | vhost-net: cleanup macros for DMA status trackingMichael S. Tsirkin2012-11-021-1/+2
|/ | | | | | | | | Better document macros for DMA tracking. Add an explicit one for DMA in progress instead of relying on user supplying len != 1. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* vhost: Separate vhost-net features from vhost featuresStefan Hajnoczi2012-07-221-2/+2
| | | | | | | | | | | | | | | | In order for other vhost devices to use the VHOST_FEATURES bits the vhost-net specific bits need to be moved to their own VHOST_NET_FEATURES constant. (Asias: Update drivers/vhost/test.c to use VHOST_NET_FEATURES) Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Cc: Zhi Yong Wu <wuzhy@cn.ibm.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Asias He <asias@redhat.com> Signed-off-by: Nicholas A. Bellinger <nab@risingtidesystems.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2012-05-161-1/+6
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| * vhost-net: fix handle_rx buffer sizeBasil Gor2012-05-111-1/+6
| | | | | | | | | | | | | | | | | | | | Take vlan header length into account, when vlan id is stored as vlan_tci. Otherwise tagged packets coming from macvtap will be truncated. Signed-off-by: Basil Gor <basil.gor@gmail.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | vhost_net: zerocopy: adding and signalling immediately when fully copiedJason Wang2012-05-021-0/+2
| | | | | | | | | | | | | | | | | | When a packet were fully copied in zerocopy, we don't wait for the DMA done to mark the done flag, so after the packet were passed to lower device, we need to add used and signal guest immediately. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* | vhost_net: re-poll only on EAGAIN or ENOBUFSJason Wang2012-05-021-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, we restart tx polling unconditionally when sendmsg() fails. This would cause unnecessary wakeups of vhost wokers and waste cpu utlization when evil userspace(guest driver) is able to hit EFAULT or EINVAL. The polling is only needed when the socket send buffer were exceeded or not enough memory. So fix this by restarting polling only when sendmsg() returns EAGAIN/ENOBUFS. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* | vhost_net: zerocopy: fix possible NULL pointer dereference of vq->bufsJason Wang2012-05-021-1/+1
|/ | | | | | | | | | | When we want to disable vhost_net backend while there's a tx work, a possible NULL pointer defernece may happen we we try to deference the vq->bufs after vhost_net_set_backend() assign a NULL to it. As suggested by Michael, fix this by checking the vq->bufs instead of vhost_sock_zcopy(). Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* skbuff: struct ubuf_info callback type safetyMichael S. Tsirkin2012-04-131-1/+1
| | | | | | | | | | | The skb struct ubuf_info callback gets passed struct ubuf_info itself, not the arg value as the field name and the function signature seem to imply. Rename the arg field to ctx to match usage, add documentation and change the callback argument type to make usage clear and to have compiler check correctness. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* vhost: fix release path lockdep checksMichael S. Tsirkin2012-02-281-1/+1
| | | | | | | | We shouldn't hold any locks on release path. Pass a flag to vhost_dev_cleanup to use the lockdep info correctly. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Sasha Levin <levinsasha928@gmail.com>
* vhost-net: add module alias (v2.1)stephen hemminger2012-01-131-3/+5
| | | | | | | | | | | | | | By adding some module aliases, programs (or users) won't have to explicitly call modprobe. Vhost-net will always be available if built into the kernel. It does require assigning a permanent minor number for depmod to work. Also: - use C99 style initialization. - add missing entry in documentation for loop-control Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Acked-By: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* vhost: handle wrap around in # of bufs mathShirley Ma2011-07-211-3/+9
| | | | | | | | | The meth for calculating the # of outstanding buffers gives incorrect results when vq->upend_idx wraps around zero. Fix that. Signed-off-by: Shirley Ma <xma@us.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost-net: update used ring on backend changeMichael S. Tsirkin2011-07-211-1/+5
| | | | | | | | | | | On backend change, we flushed out outstanding skbs but forgot to update the used ring, so that done entries were left in the ubuf_info ring. As a result we lose heads or complete incorrect ones, crashing the guest or leaking memory. Fix by updating the used ring. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost: init used ring after backend was setJason Wang2011-07-191-0/+4
| | | | | | | | | | Move the used ring initialization after backend was set. This makes it possible to disable the backend and tweak the used ring, then restart. This will also make it possible to log the used ring write correctly. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost: vhost TX zero-copy supportMichael S. Tsirkin2011-07-181-1/+76
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | >From: Shirley Ma <mashirle@us.ibm.com> This adds experimental zero copy support in vhost-net, disabled by default. To enable, set experimental_zcopytx module option to 1. This patch maintains the outstanding userspace buffers in the sequence it is delivered to vhost. The outstanding userspace buffers will be marked as done once the lower device buffers DMA has finished. This is monitored through last reference of kfree_skb callback. Two buffer indices are used for this purpose. The vhost-net device passes the userspace buffers info to lower device skb through message control. DMA done status check and guest notification are handled by handle_tx: in the worst case is all buffers in the vq are in pending/done status, so we need to notify guest to release DMA done buffers first before we get any new buffers from the vq. One known problem is that if the guest stops submitting buffers, buffers might never get used until some further action, e.g. device reset. This does not seem to affect linux guests. Signed-off-by: Shirley <xma@us.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* vhost: support event indexMichael S. Tsirkin2011-05-301-6/+6
| | | | | | | | Support the new event index feature. When acked, utilize it to reduce the # of interrupts sent to the guest. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* vhost-net: remove unlocked use of receive_queueMichael S. Tsirkin2011-03-131-1/+1
| | | | | | | | | Use of skb_queue_empty(&sock->sk->sk_receive_queue) without taking the sk_receive_queue.lock is unsafe or useless. Take it out. Reported-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost: lock receive queue, not the socketJason Wang2011-03-131-3/+4
| | | | | | | | | vhost takes a sock lock to try and prevent the skb from being pulled from the receive queue after skb_peek. However this is not the right lock to use for that, sk_receive_queue.lock is. Fix that up. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost-net: Unify the code of mergeable and big buffer handlingJason Wang2011-03-131-121/+7
| | | | | | | | | | | | Codes duplication were found between the handling of mergeable and big buffers, so this patch tries to unify them. This could be easily done by adding a quota to the get_rx_bufs() which is used to limit the number of buffers it returns (for mergeable buffer, the quota is simply UIO_MAXIOV, for big buffers, the quota is just 1), and then the previous handle_rx_mergeable() could be resued also for big buffers. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost-net: check the support of mergeable buffer outside the receive loopJason Wang2011-03-131-2/+3
| | | | | | | | | No need to check the support of mergeable buffer inside the recevie loop as the whole handle_rx()_xx is in the read critical region. So this patch move it ahead of the receiving loop. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost: Cleanup vhost.c and net.cKrishna Kumar2011-03-081-7/+12
| | | | | | | Minor cleanup of vhost.c and net.c to match coding style. Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vhost: rcu annotation fixupMichael S. Tsirkin2011-02-011-4/+5
| | | | | | | | | | | | | When built with rcu checks enabled, vhost triggers bogus warnings as vhost features are read without dev->mutex sometimes, and private pointer is read with our kind of rcu where work serves as a read side critical section. Fixing it properly is not trivial. Disable the warnings by stubbing out the checks for now. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* Merge branch 'vhost-net-next' of ↵David S. Miller2010-12-141-8/+1
|\ | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
| * vhost: fix typos in commentJason Wang2010-12-091-1/+1
| | | | | | | | | | Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| * vhost-net: batch use/unuse mmMichael S. Tsirkin2010-11-041-7/+0
| | | | | | | | | | | | | | Move use/unuse mm to vhost.c which makes it possible to batch these operations. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* | vhost/net: fix rcu check usageMichael S. Tsirkin2010-11-251-2/+3
|/ | | | | | | | Incorrect rcu check was used as rcu isn't done under mutex here. Force check to 1 for now, to stop it from complaining. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6Linus Torvalds2010-10-231-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1699 commits) bnx2/bnx2x: Unsupported Ethtool operations should return -EINVAL. vlan: Calling vlan_hwaccel_do_receive() is always valid. tproxy: use the interface primary IP address as a default value for --on-ip tproxy: added IPv6 support to the socket match cxgb3: function namespace cleanup tproxy: added IPv6 support to the TPROXY target tproxy: added IPv6 socket lookup function to nf_tproxy_core be2net: Changes to use only priority codes allowed by f/w tproxy: allow non-local binds of IPv6 sockets if IP_TRANSPARENT is enabled tproxy: added tproxy sockopt interface in the IPV6 layer tproxy: added udp6_lib_lookup function tproxy: added const specifiers to udp lookup functions tproxy: split off ipv6 defragmentation to a separate module l2tp: small cleanup nf_nat: restrict ICMP translation for embedded header can: mcp251x: fix generation of error frames can: mcp251x: fix endless loop in interrupt handler if CANINTF_MERRF is set can-raw: add msg_flags to distinguish local traffic 9p: client code cleanup rds: make local functions/variables static ... Fix up conflicts in net/core/dev.c, drivers/net/pcmcia/smc91c92_cs.c and drivers/net/wireless/ath/ath9k/debug.c as per David
| * vhost: max s/g to match qemuJason Wang2010-10-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Qemu supports up to UIO_MAXIOV s/g so we have to match that because guest drivers may rely on this. Allocate indirect and log arrays dynamically to avoid using too much contigious memory and make the length of hdr array to match the header length since each iovec entry has a least one byte. Test with copying large files w/ and w/o migration in both linux and windows guests. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* | Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bklLinus Torvalds2010-10-221-0/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl: vfs: make no_llseek the default vfs: don't use BKL in default_llseek llseek: automatically add .llseek fop libfs: use generic_file_llseek for simple_attr mac80211: disallow seeks in minstrel debug code lirc: make chardev nonseekable viotape: use noop_llseek raw: use explicit llseek file operations ibmasmfs: use generic_file_llseek spufs: use llseek in all file operations arm/omap: use generic_file_llseek in iommu_debug lkdtm: use generic_file_llseek in debugfs net/wireless: use generic_file_llseek in debugfs drm: use noop_llseek
| * | llseek: automatically add .llseek fopArnd Bergmann2010-10-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
* | | Merge commit 'v2.6.36-rc7' into core/rcuIngo Molnar2010-10-071-1/+1
|\ \ \ | | |/ | |/| | | | | | | | | | Merge reason: Update from -rc3 to -rc7. Signed-off-by: Ingo Molnar <mingo@elte.hu>
generated by cgit v1.2.3 (git 2.25.1) at 2024-08-29 22:16:10 +0000