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* Input: uinput - add devname alias to allow module on-demand loadKay Sievers2010-08-211-0/+1
| | | | | | | | | | | | Recent modprobe and udev versions allow to create device nodes for modules which are not loaded. Only the first access will cause the in-kernel module loader to pull-in the module. Systems which never access the device node will not needlessly load the module, and no longer need init scripts or other facilities to unconditionally load it. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
* dm: allow autoloading of dm modPeter Rajnoha2010-08-121-0/+1
| | | | | | | | | Add devname:mapper/control and MAPPER_CTRL_MINOR module alias to support dm-mod module autoloading. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Peter Rajnoha <prajnoha@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* misc: Fix allocation 'borrowed' by vhost_netAlan Cox2010-06-091-1/+6
| | | | | | | | | | | | | | | 10, 233 is allocated officially to /dev/kmview which is shipping in Ubuntu and Debian distributions. vhost_net seem to have borrowed it without making a proper request and this causes regressions in the other distributions. vhost_net can use a dynamic minor so use that instead. Also update the file with a comment to try and avoid future misunderstandings. cc: stable@kernel.org Signed-off-by: Alan Cox <device@lanana.org> [ We should have caught this before 2.6.34 got released. - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* driver core: add devname module aliases to allow module on-demand auto-loadingKay Sievers2010-05-251-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds: alias: devname:<name> to some common kernel modules, which will allow the on-demand loading of the kernel module when the device node is accessed. Ideally all these modules would be compiled-in, but distros seems too much in love with their modularization that we need to cover the common cases with this new facility. It will allow us to remove a bunch of pretty useless init scripts and modprobes from init scripts. The static device node aliases will be carried in the module itself. The program depmod will extract this information to a file in the module directory: $ cat /lib/modules/2.6.34-00650-g537b60d-dirty/modules.devname # Device nodes to trigger on-demand module loading. microcode cpu/microcode c10:184 fuse fuse c10:229 ppp_generic ppp c108:0 tun net/tun c10:200 dm_mod mapper/control c10:235 Udev will pick up the depmod created file on startup and create all the static device nodes which the kernel modules specify, so that these modules get automatically loaded when the device node is accessed: $ /sbin/udevd --debug ... static_dev_create_from_modules: mknod '/dev/cpu/microcode' c10:184 static_dev_create_from_modules: mknod '/dev/fuse' c10:229 static_dev_create_from_modules: mknod '/dev/ppp' c108:0 static_dev_create_from_modules: mknod '/dev/net/tun' c10:200 static_dev_create_from_modules: mknod '/dev/mapper/control' c10:235 udev_rules_apply_static_dev_perms: chmod '/dev/net/tun' 0666 udev_rules_apply_static_dev_perms: chmod '/dev/fuse' 0666 A few device nodes are switched to statically allocated numbers, to allow the static nodes to work. This might also useful for systems which still run a plain static /dev, which is completely unsafe to use with any dynamic minor numbers. Note: The devname aliases must be limited to the *common* and *single*instance* device nodes, like the misc devices, and never be used for conceptually limited systems like the loop devices, which should rather get fixed properly and get a control node for losetup to talk to, instead of creating a random number of device nodes in advance, regardless if they are ever used. This facility is to hide the mess distros are creating with too modualized kernels, and just to hide that these modules are not compiled-in, and not to paper-over broken concepts. Thanks! :) Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: David S. Miller <davem@davemloft.net> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Chris Mason <chris.mason@oracle.com> Cc: Alasdair G Kergon <agk@redhat.com> Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk> Cc: Ian Kent <raven@themaw.net> Signed-Off-By: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* vhost_net: a kernel-level virtio serverMichael S. Tsirkin2010-01-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | What it is: vhost net is a character device that can be used to reduce the number of system calls involved in virtio networking. Existing virtio net code is used in the guest without modification. There's similarity with vringfd, with some differences and reduced scope - uses eventfd for signalling - structures can be moved around in memory at any time (good for migration, bug work-arounds in userspace) - write logging is supported (good for migration) - support memory table and not just an offset (needed for kvm) common virtio related code has been put in a separate file vhost.c and can be made into a separate module if/when more backends appear. I used Rusty's lguest.c as the source for developing this part : this supplied me with witty comments I wouldn't be able to write myself. What it is not: vhost net is not a bus, and not a generic new system call. No assumptions are made on how guest performs hypercalls. Userspace hypervisors are supported as well as kvm. How it works: Basically, we connect virtio frontend (configured by userspace) to a backend. The backend could be a network device, or a tap device. Backend is also configured by userspace, including vlan/mac etc. Status: This works for me, and I haven't see any crashes. Compared to userspace, people reported improved latency (as I save up to 4 system calls per packet), as well as better bandwidth and CPU utilization. Features that I plan to look at in the future: - mergeable buffers - zero copy - scalability tuning: figure out the best threading model to use Note on RCU usage (this is also documented in vhost.h, near private_pointer which is the value protected by this variant of RCU): what is happening is that the rcu_dereference() is being used in a workqueue item. The role of rcu_read_lock() is taken on by the start of execution of the workqueue item, of rcu_read_unlock() by the end of execution of the workqueue item, and of synchronize_rcu() by flush_workqueue()/flush_work(). In the future we might need to apply some gcc attribute or sparse annotation to the function passed to INIT_WORK(). Paul's ack below is for this RCU usage. (Includes fixes by Alan Cox <alan@linux.intel.com>, David L Stevens <dlstevens@us.ibm.com>, Chris Wright <chrisw@redhat.com>) Acked-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Driver-Core: extend devnode callbacks to provide permissionsKay Sievers2009-09-191-1/+2
| | | | | | | | | | | | | This allows subsytems to provide devtmpfs with non-default permissions for the device node. Instead of the default mode of 0600, null, zero, random, urandom, full, tty, ptmx now have a mode of 0666, which allows non-privileged processes to access standard device nodes in case no other userspace process applies the expected permissions. This also fixes a wrong assignment in pktcdvd and a checkpatch.pl complain. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Driver Core: misc: add nodename support for misc devices.Kay Sievers2009-06-151-0/+1
| | | | | | | | | | | This adds support for misc devices to report their requested nodename to userspace. It also updates a number of misc drivers to provide the needed subdirectory and device name to be used for them. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Jan Blunck <jblunck@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* [SCSI] mpt2sas: add MPT2SAS_MINOR(221) to miscdevice.hEric Moore2009-03-131-0/+1
| | | | | Signed-off-by: Eric Moore <eric.moore@lsi.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* fuse: move FUSE_MINOR to miscdevice.hTejun Heo2008-11-261-21/+21
| | | | | | | Move FUSE_MINOR to miscdevice.h. While at it, de-uglify the file. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* PM: Remove destroy_suspended_device()Rafael J. Wysocki2008-04-191-9/+1
| | | | | | | | | | | | | | | | | | After 2.6.24 there was a plan to make the PM core acquire all device semaphores during a suspend/hibernation to protect itself from concurrent operations involving device objects. That proved to be too heavy-handed and we found a better way to achieve the goal, but before it happened, we had introduced the functions device_pm_schedule_removal() and destroy_suspended_device() to allow drivers to "safely" destroy a suspended device and we had adapted some drivers to use them. Now that these functions are no longer necessary, it seems reasonable to remove them and modify their users to use the normal device unregistration instead. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Misc: Add possibility to remove misc devices during suspend/resumeRafael J. Wysocki2008-02-051-1/+9
| | | | | | | | | | | | | | | | | Make it possible to unregister a misc device object in a safe way during a suspend/resume cycle. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Michael Buesch <mb@bu3sch.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Len Brown <lenb@kernel.org> Cc: Greg KH <greg@kroah.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* KVM: Use own minor numberAvi Kivity2007-05-031-0/+1
| | | | | | Use the minor number (232) allocated to kvm by lanana. Signed-off-by: Avi Kivity <avi@qumranet.com>
* Driver core: change misc class_devices to be real devicesGreg Kroah-Hartman2006-12-011-3/+2
| | | | | | | | This also ment that some of the misc drivers had to also be fixed up as they were assuming the device was a class_device. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* [PATCH] devfs: Remove the miscdevice devfs_name field as it's no longer neededGreg Kroah-Hartman2006-06-261-1/+0
| | | | | | Also fixes all drivers that set this field. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* [PATCH] mark f_ops const in the inodeArjan van de Ven2006-03-281-1/+1
| | | | | | | | | | | Mark the f_ops members of inodes as const, as well as fix the ripple-through this causes by places that copy this f_ops and then "do stuff" with it. Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-161-0/+52
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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