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path: root/drivers/hv/hv_utils_transport.c
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2018-02-11vfs: do bulk POLL* -> EPOLL* replacementLinus Torvalds
This is the mindless scripted replacement of kernel use of POLL* variables as described by Al, done by this script: for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'` for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done done with de-mangling cleanups yet to come. NOTE! On almost all architectures, the EPOLL* constants have the same values as the POLL* constants do. But they keyword here is "almost". For various bad reasons they aren't the same, and epoll() doesn't actually work quite correctly in some cases due to this on Sparc et al. The next patch from Al will sort out the final differences, and we should be all done. Scripted-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-28the rest of drivers/*: annotate ->poll() instancesAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-16Drivers: hv: util: move waiting for release to hv_utils_transport itselfVitaly Kuznetsov
Waiting for release_event in all three drivers introduced issues on release as on_reset() hook is not always called. E.g. if the device was never opened we will never get the completion. Move the waiting code to hvutil_transport_destroy() and make sure it is only called when the device is open. hvt->lock serialization should guarantee the absence of races. Fixes: 5a66fecbf6aa ("Drivers: hv: util: kvp: Fix a rescind processing issue") Fixes: 20951c7535b5 ("Drivers: hv: util: Fcopy: Fix a rescind processing issue") Fixes: d77044d142e9 ("Drivers: hv: util: Backup: Fix a rescind processing issue") Reported-by: Dexuan Cui <decui@microsoft.com> Tested-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31Drivers: hv: utils: fix a race on userspace daemons registrationVitaly Kuznetsov
Background: userspace daemons registration protocol for Hyper-V utilities drivers has two steps: 1) daemon writes its own version to kernel 2) kernel reads it and replies with module version at this point we consider the handshake procedure being completed and we do hv_poll_channel() transitioning the utility device to HVUTIL_READY state. At this point we're ready to handle messages from kernel. When hvutil_transport is in HVUTIL_TRANSPORT_CHARDEV mode we have a single buffer for outgoing message. hvutil_transport_send() puts to this buffer and till the buffer is cleared with hvt_op_read() returns -EFAULT to all consequent calls. Host<->guest protocol guarantees there is no more than one request at a time and we will not get new requests till we reply to the previous one so this single message buffer is enough. Now to the race. When we finish negotiation procedure and send kernel module version to userspace with hvutil_transport_send() it goes into the above mentioned buffer and if the daemon is slow enough to read it from there we can get a collision when a request from the host comes, we won't be able to put anything to the buffer so the request will be lost. To solve the issue we need to know when the negotiation is really done (when the version message is read by the daemon) and transition to HVUTIL_READY state after this happens. Implement a callback on read to support this. Old style netlink communication is not affected by the change, we don't really know when these messages are delivered but we don't have a single message buffer there. Reported-by: Barry Davis <barry_davis@stormagic.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-01Drivers: hv: utils: Remove util transport handler from list if registration ↵Alex Ng
fails If util transport fails to initialize for any reason, the list of transport handlers may become corrupted due to freeing the transport handler without removing it from the list. Fix this by cleaning it up from the list. Signed-off-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-21Drivers: hv: utils: fix hvt_op_poll() return value on transport destroyVitaly Kuznetsov
The return type of hvt_op_poll() is unsigned int and -EBADF is inappropriate, poll functions return POLL* statuses. Reported-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14Drivers: hv: utils: fix crash when device is removed from host sideVitaly Kuznetsov
The crash is observed when a service is being disabled host side while userspace daemon is connected to the device: [ 90.244859] general protection fault: 0000 [#1] SMP ... [ 90.800082] Call Trace: [ 90.800082] [<ffffffff81187008>] __fput+0xc8/0x1f0 [ 90.800082] [<ffffffff8118716e>] ____fput+0xe/0x10 ... [ 90.800082] [<ffffffff81015278>] do_signal+0x28/0x580 [ 90.800082] [<ffffffff81086656>] ? finish_task_switch+0xa6/0x180 [ 90.800082] [<ffffffff81443ebf>] ? __schedule+0x28f/0x870 [ 90.800082] [<ffffffffa01ebbaa>] ? hvt_op_read+0x12a/0x140 [hv_utils] ... The problem is that hvutil_transport_destroy() which does misc_deregister() freeing the appropriate device is reachable by two paths: module unload and from util_remove(). While module unload path is protected by .owner in struct file_operations util_remove() path is not. Freeing the device while someone holds an open fd for it is a show stopper. In general, it is not possible to revoke an fd from all users so the only way to solve the issue is to defer freeing the hvutil_transport structure. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14Drivers: hv: utils: introduce HVUTIL_TRANSPORT_DESTROY modeVitaly Kuznetsov
When Hyper-V host asks us to remove some util driver by closing the appropriate channel there is no easy way to force the current file descriptor holder to hang up but we can start to respond -EBADF to all operations asking it to exit gracefully. As we're setting hvt->mode from two separate contexts now we need to use a proper locking. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14Drivers: hv: utils: rename outmsg_lockVitaly Kuznetsov
As a preparation to reusing outmsg_lock to protect test-and-set openrations on 'mode' rename it the more general 'lock'. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14Drivers: hv: utils: fix memory leak on on_msg() failureVitaly Kuznetsov
inmsg should be freed in case of on_msg() failure to avoid memory leak. Preserve the error code from on_msg(). Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14Drivers: hv: utils: use memdup_user in hvt_op_writeOlaf Hering
Use memdup_user to handle OOM. Fixes: 14b50f80c32d ('Drivers: hv: util: introduce hv_utils_transport abstraction') Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14Drivers: hv: util: catch allocation errorsOlaf Hering
Catch allocation errors in hvutil_transport_send. Fixes: 14b50f80c32d ('Drivers: hv: util: introduce hv_utils_transport abstraction') Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04hv: util: checking the wrong variableDan Carpenter
We don't catch this allocation failure because there is a typo and we check the wrong variable. Fixes: 14b50f80c32d ('Drivers: hv: util: introduce hv_utils_transport abstraction') Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24Drivers: hv: util: introduce hv_utils_transport abstractionVitaly Kuznetsov
The intention is to make KVP/VSS drivers work through misc char devices. Introduce an abstraction for kernel/userspace communication to make the migration smoother. Transport operational mode (netlink or char device) is determined by the first received message. To support driver upgrades the switch from netlink to chardev operational mode is supported. Every hv_util daemon is supposed to register 2 callbacks: 1) on_msg() to get notified when the userspace daemon sent a message; 2) on_reset() to get notified when the userspace daemon drops the connection. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>