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Give the device major / minor numbers their own separate 32 bit fields in the kernel. Change dev_ops to use a RB tree to index major device numbers and remove the 256 device major number limitation. Build a dynamic major number assignment feature into dev_ops_add() and adjust ASR (which already had a hand-rolled one), and MFS to use the feature. MFS at least does not require any filesystem visibility to access its backing device. Major devices numbers >= 256 are used for dynamic assignment. Retain filesystem compatibility for device numbers that fall within the range that can be represented in UFS or struct stat (which is a single 32 bit field supporting 8 bit major numbers and 24 bit minor numbers).
Replace NOCDEV with NULL. NOCDEV was ((void *)-1) and as inherited from *BSD a long time ago due to the device pointer / device number duality. Now that the pointer and device number has been separated, we can just use NULL to indicate no-pointer. Replace si_refs with si_sysref. Use SYSREF for ref-count cdev_t. Enable cdev_t reclamation on deletion.
Changes to consdev - low level kernel console initialization. The consdev API was calling make_dev() extremely early in the boot sequence, but except for a little code in syscons didn't really need the abstraction to operate the kernel console during boot. Change the consdev API to no longer require the use the device abstraction to operate. This will allow the device ABI (cdev_t) to be converted to use SYSREF.
Follow up to kern_conf.c 1.16. We can't just ignore the ops comparison, it is needed to keep user-invisible devices user-invisible. Add a flag so hashdev() knows when it can ignore the comparison and when it can't ignore the comparison.
Change the kernel dev_t, representing a pointer to a specinfo structure, to cdev_t. Change struct specinfo to struct cdev. The name 'cdev' was taken from FreeBSD. Remove the dev_t shim for the kernel. This commit generally removes the overloading of 'dev_t' between userland and the kernel. Also fix a bug in libkvm where a kernel dev_t (now cdev_t) was not being properly converted to a userland dev_t.
Rename struct specinfo into struct cdev. Add a new typedef 'cdev_t' for cdev pointers. Temporarily retain dev_t for cdev pointers until the kernel can be converted over to cdev_t.
Rename functions to avoid conflicts with libc.
MASSIVE reorganization of the device operations vector. Change cdevsw to dev_ops. dev_ops is a syslink-compatible operations vector structure similar to the vop_ops structure used by vnodes. Remove a huge number of instances where a thread pointer is still being passed as an argument to various device ops and other related routines. The device OPEN and IOCTL calls now take a ucred instead of a thread pointer, and the CLOSE call no longer takes a thread pointer.
Make the entire BUF/BIO system BIO-centric instead of BUF-centric. Vnode and device strategy routines now take a BIO and must pass that BIO to biodone(). All code which previously managed a BUF undergoing I/O now manages a BIO. The new BIO-centric algorithms allow BIOs to be stacked, where each layer represents a block translation, completion callback, or caller or device private data. This information is no longer overloaded within the BUF. Translation layer linkages remain intact as a 'cache' after I/O has completed. The VOP and DEV strategy routines no longer make assumptions as to which translated block number applies to them. The use the block number in the BIO specifically passed to them. Change the 'untranslated' constant to NOOFFSET (for bio_offset), and (daddr_t)-1 (for bio_blkno). Rip out all code that previously set the translated block number to the untranslated block number to indicate that the translation had not been made. Rip out all the cluster linkage fields for clustered VFS and clustered paging operations. Clustering now occurs in a private BIO layer using private fields within the BIO. Reformulate the vn_strategy() and dev_dstrategy() abstraction(s). These routines no longer assume that bp->b_vp == the vp of the VOP operation, and the dev_t is no longer stored in the struct buf. Instead, only the vp passed to vn_strategy() (and related *_strategy() routines for VFS ops), and the dev_t passed to dev_dstrateg() (and related *_strategy() routines for device ops) is used by the VFS or DEV code. This will allow an arbitrary number of translation layers in the future. Create an independant per-BIO tracking entity, struct bio_track, which is used to determine when I/O is in-progress on the associated device or vnode. NOTE: Unlike FreeBSD's BIO work, our struct BUF is still used to hold the fields describing the data buffer, resid, and error state. Major-testing-by: Stefan Krueger
Track the last read and last write timestamp at the device level and modify the stat code to retrieve the information. This is so devices such as ttys report the correct access/modified time for the 'w' and related utilities. NOTE: the inode still needs to be updated at CLOSE time to record the last accessed and modified times persistently, and this is not yet occuring. This is necessary because device read/write now bypasses the filesystem VOP code.
When booting from CD, check cd1a and acd1a after cd0a and acd0a, allowing a CD to be booted off of a second CDRom drive. When checking for the same rootdev selection as already has been set, only the major number of the existing rootdev was being checked. This prevent other unit numbers from being tried properly (e.g. trying cd1 after having already tried cd0). Completely parse the rootdev's (unit, slice, partition) tuple before trying to look up the device, rather then assuming that devname(0,0,0) will exist (this is no longer necessarily true).
Device layer rollup commit. * cdevsw_add() is now required. cdevsw_add() and cdevsw_remove() may specify a mask/match indicating the range of supported minor numbers. Multiple cdevsw_add()'s using the same major number, but distinctly different ranges, may be issued. All devices that failed to call cdevsw_add() before now do. * cdevsw_remove() now automatically marks all devices within its supported range as being destroyed. * vnode->v_rdev is no longer resolved when the vnode is created. Instead, only v_udev (a newly added field) is resolved. v_rdev is resolved when the vnode is opened and cleared on the last close. * A great deal of code was making rather dubious assumptions with regards to the validity of devices associated with vnodes, primarily due to the persistence of a device structure due to being indexed by (major, minor) instead of by (cdevsw, major, minor). In particular, if you run a program which connects to a USB device and then you pull the USB device and plug it back in, the vnode subsystem will continue to believe that the device is open when, in fact, it isn't (because it was destroyed and recreated). In particular, note that all the VFS mount procedures now check devices via v_udev instead of v_rdev prior to calling VOP_OPEN(), since v_rdev is NULL prior to the first open. * The disk layer's device interaction has been rewritten. The disk layer (i.e. the slice and disklabel management layer) no longer overloads its data onto the device structure representing the underlying physical disk. Instead, the disk layer uses the new cdevsw_add() functionality to register its own cdevsw using the underlying device's major number, and simply does NOT register the underlying device's cdevsw. No confusion is created because the device hash is now based on (cdevsw,major,minor) rather then (major,minor). NOTE: This also means that underlying raw disk devices may use the entire device minor number instead of having to reserve the bits used by the disk layer, and also means that can we (theoretically) stack a fully disklabel-supported 'disk' on top of any block device. * The new reference counting scheme prevents this by associating a device with a cdevsw and disconnecting the device from its cdevsw when the cdevsw is removed. Additionally, all udev2dev() lookups run through the cdevsw mask/match and only successfully find devices still associated with an active cdevsw. * Major work on MFS: MFS no longer shortcuts vnode and device creation. It now creates a real vnode and a real device and implements real open and close VOPs. Additionally, due to the disk layer changes, MFS is no longer limited to 255 mounts. The new limit is 16 million. Since MFS creates a real device node, mount_mfs will now create a real /dev/mfs<PID> device that can be read from userland (e.g. so you can dump an MFS filesystem). * BUF AND DEVICE STRATEGY changes. The struct buf contains a b_dev field. In order to properly handle stacked devices we now require that the b_dev field be initialized before the device strategy routine is called. This required some additional work in various VFS implementations. To enforce this requirement, biodone() now sets b_dev to NODEV. The new disk layer will adjust b_dev before forwarding a request to the actual physical device. * A bug in the ISO CD boot sequence which resulted in a panic has been fixed. Testing by: lots of people, but David Rhodus found the most aggregious bugs.
device switch 1/many: Remove d_autoq, add d_clone (where d_autoq was). d_autoq was used to allow the device port dispatch to mix old-style synchronous calls with new style messaging calls within a particular device. It was never used for that purpose. d_clone will be more fully implemented as work continues. We are going to install d_port in the dev_t (struct specinfo) structure itself and d_clone will be needed to allow devices to 'revector' the port on a minor-number by minor-number basis, in particular allowing minor numbers to be directly dispatched to distinct threads. This is something we will be needing later on.
DEV messaging stage 2/4: In this stage all DEV commands are now being funneled through the message port for action by the port's beginmsg function. CONSOLE and DISK device shims replace the port with their own and then forward to the original. FB (Frame Buffer) shims supposedly do the same thing but I haven't been able to test it. I don't expect instability in mainline code but there might be easy-to-fix, and some drivers still need to be converted. See primarily: kern/kern_device.c (new dev_*() functions and inherits cdevsw code from kern/kern_conf.c), sys/device.h, and kern/subr_disk.c for the high points. In this stage all DEV messages are still acted upon synchronously in the context of the caller. We cannot create a separate handler thread until the copyin's (primarily in ioctl functions) are made thread-aware. Note that the messaging shims are going to look rather messy in these early days but as more subsystems are converted over we will begin to use pre-initialized messages and message forwarding to avoid having to constantly rebuild messages prior to use. Note that DEV itself is a mess oweing to its 4.x roots and will be cleaned up in subsequent passes. e.g. the way sub-devices inherit the main device's cdevsw was always a bad hack and it still is, and several functions (mmap, kqfilter, psize, poll) return results rather then error codes, which will be fixed since now we have a message to store the result in :-)
DEV messaging stage 1/4: Rearrange struct cdevsw and add a message port and auto-queueing mask. The mask will tell us which message functions can be safely queued to another thread and which still need to run in the context of the caller. Primary configuration fields (name, cmaj, flags, port, autoq mask) are now at the head of the structure. Function vectors, which may eventually go away, are at the end. The port and autoq fields are non-functional in this stage. The old BDEV device major number support has also been removed from cdevsw, and code has been added to translate the bootdev passed from the boot code (the boot code has always passed the now defunct block device major numbers and we obviously need to keep that compatibility intact).
proc->thread stage 2: MAJOR revamping of system calls, ucred, jail API, and some work on the low level device interface (proc arg -> thread arg). As -current did, I have removed p_cred and incorporated its functions into p_ucred. p_prison has also been moved into p_ucred and adjusted accordingly. The jail interface tests now uses ucreds rather then processes. The syscall(p,uap) interface has been changed to just (uap). This is inclusive of the emulation code. It makes little sense to pass a proc pointer around which confuses the MP readability of the code, because most system call code will only work with the current process anyway. Note that eventually *ALL* syscall emulation code will be moved to a kernel-protected userland layer because it really makes no sense whatsoever to implement these emulations in the kernel. suser() now takes no arguments and only operates with the current process. The process argument has been removed from suser_xxx() so it now just takes a ucred and flags. The sysctl interface was adjusted somewhat.
Add the DragonFly cvs id and perform general cleanups on cvs/rcs/sccs ids. Most ids have been removed from !lint sections and moved into comment sections.
import from FreeBSD RELENG_4 22.214.171.124