To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
See comments in the function header for details. The new interface will
be used in a follow-on patch.
Changelog [v2]:
[Dave Hansen] Replace get_sb_ref() in fs/super.c with get_init_pts_sb()
and make the new interface private to devpts
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
/dev/ptmx is closely tied to the devpts filesystem. An open of /dev/ptmx,
allocates the next pty index and the associated device shows up in the
devpts fs as /dev/pts/n.
Wih multiple instancs of devpts filesystem, during an open of /dev/ptmx
we would be unable to determine which instance of the devpts is being
accessed.
So we move the 'ptmx' node into /dev/pts and use the inode of the 'ptmx'
node to identify the superblock and hence the devpts instance. This patch
adds ability for the kernel to internally create the [ptmx, c, 5:2] device
when mounting devpts filesystem. Since the ptmx node in devpts is new and
may surprise some userspace scripts, the default permissions for the new
node is 0000. These permissions can be changed either using chmod or by
remounting with the new '-o ptmxmode=0666' mount option.
Changelog[v5]:
- [Serge Hallyn bugfix]: Letting new_inode() assign inode number to
ptmx can collide with hand-assigning inode numbers to ptys. So,
hand-assign specific inode number to ptmx node also.
- [Serge Hallyn]: Maybe safer to grab root dentry mutex while creating
ptmx node
- [Bugfix with Serge Hallyn] Replace lookup_one_len() in mknod_ptmx()
wih d_alloc_name() (lookup during ->get_sb() locks up system). To
simplify patchset, fold the ptmx_dentry patch into this.
Changelog[v4]:
- Change default permissions of pts/ptmx node to 0000.
- Move code for ptmxmode under #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES.
Changelog[v3]:
- Rename ptmx_mode to ptmxmode (for consistency with 'newinstance')
Changelog[v2]:
- [H. Peter Anvin] Remove mknod() system call support and create the
ptmx node internally.
Changelog[v1]:
- Earlier version of this patch enabled creating /dev/pts/tty as
well. As pointed out by Al Viro and H. Peter Anvin, that is not
really necessary.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move code to parse mount options into a separate function so it can
(later) be shared between mount and remount operations.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With support for multiple mounts of devpts, the 'config' structure really
represents per-mount options rather than config parameters. Rename 'config'
structure to 'pts_mount_opts' and store it in the super-block.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To enable multiple mounts of devpts, 'allocated_ptys' must be a per-mount
variable rather than a global variable. Move 'allocated_ptys' into the
super_block's s_fs_info.
Changelog[v2]:
Define and use DEVPTS_SB() wrapper.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the 'devpts_root' global variable and find the root dentry using
the super_block. The super-block can be found from the device inode, using
the new wrapper, pts_sb_from_inode().
Changelog: This patch is based on an earlier patchset from Serge Hallyn
and Matt Helsley.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes the loss of echoed (and other ldisc-generated characters) when
the tty is stopped or when the driver output buffer is full (happens
frequently for input during continuous program output, such as ^C)
and removes the Big Kernel Lock from the N_TTY line discipline.
Adds an "echo buffer" to the N_TTY line discipline that handles all
ldisc-generated output (including echoed characters). Along with the
loss of characters, this also fixes the associated loss of sync between
tty output and the ldisc state when characters cannot be immediately
written to the tty driver.
The echo buffer stores (in addition to characters) state operations that need
to be done at the time of character output (like management of the column
position). This allows echo to cooperate correctly with program output,
since the ldisc state remains consistent with actual characters written.
Since the echo buffer code now isolates the tty column state code
to the process_out* and process_echoes functions, we can remove the
Big Kernel Lock (BKL) and replace it with mutex locks.
Highlights are:
* Handles echo (and other ldisc output) when tty driver buffer is full
- continuous program output can block echo
* Saves echo when tty is in stopped state (e.g. ^S)
- (e.g.: ^Q will correctly cause held characters to be released for output)
* Control character pairs (e.g. "^C") are treated atomically and not
split up by interleaved program output
* Line discipline state is kept consistent with characters sent to
the tty driver
* Remove the big kernel lock (BKL) from N_TTY line discipline
Signed-off-by: Joe Peterson <joe@skyrush.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add spin_lock_irqsave() when receive and transfer data.
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug description:
The IRDA receiver may can't receiving any more after processed some signals.
To duplicate this issue is put three IRDA devices together, one blackfin,
two none blackfin, they will detect each other. Let one none blackfin devices
irdaping the blackfin devices, when it stopped print out ping information,
it is the time that blackfin stoped receiving, the time is random.
The related register bit is OK, the other devices is sending data continuously.
But no interrupt come.
Fixing:
I tried Michael's suggestion that request the UARTx error interrupt, and reset
the IRDA when found FE error. This method helps much, but it can't completely
avoid stop.
Reset the IRDA before every time sending the data is more safe.
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: cleanup
We now have a cleaner check for gcc 4.1.0/4.1.1 trouble in
include/linux/compiler-gcc4.h, so remove the 4.1.0 quirk from
init/main.c.
Reported-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These compiler versions are known to miscompile __weak functions and
thus generate kernels that don't necessarily work correctly. If a weak
function is int he same compilation unit as a caller, gcc may end up
inlining it, and thus binding the weak function too early.
See
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
for details.
Cc: Adrian Bunk <bunk@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- include the gcc version-dependent header files from the generic gcc
header file, rather than the other way around (iow: don't make the
non-gcc header file have to know about gcc versions)
- don't include compiler-gcc4.h for gcc 5 (for whenever it gets
released). That's just confusing and made us do odd things in the
gcc4 header file (testing that we really had version 4!)
- generate the name from the __GNUC__ version directly, rather than
having a mess of #if conditionals.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: fix crash on x86/UV
UV is the SGI "UltraViolet" machine, which is x86_64 based.
BAU is the "Broadcast Assist Unit", used for TLB shootdown in UV.
This patch removes the allocation and initialization of an unused table.
This table is left over from a development test mode. It is unused in
the present code.
And it was incorrectly initialized: 8 entries allocated but 17 initialized,
causing slab corruption.
This patch should go into 2.6.27 and 2.6.28 as well as the current tree.
Diffed against 2.6.28 (linux-next, 12/30/08)
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The pda rework (commit 3461b0af02)
to remove static boot cpu pdas introduced a performance bug.
_boot_cpu_pda is the actual pda used by the boot cpu and is definitely
not "__read_mostly" and ended up polluting the read mostly section with
writes. This bug caused regression of about 8-10% on certain syscall
intensive workloads.
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Acked-by: Mike Travis <travis@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Remove cdrom_do_newpc_cont and cdrom_start_rw_cont wrappers and pass
cdrom_transfer_packet_command to ide_execute_command directly.
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
[bart: don't move cdrom_start_packet_command() around, remove newlines]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
[bart: move cmd_len check closer to ->output_data() call]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
As a result, remove now unused ide_scsi_get_timeout and ide_scsi_expiry.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
In addition, we wait for DRQ to be asserted by repeatedly polling
device status no matter what DRQ type each device implements.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
... by factoring it out of ide_cd_do_request() into a helper, as suggested by
Bart.
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
[bart: BLK_DEV_IDECD needs to select IDE_ATAPI now]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
There should be no functional change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
As planed, this removes ide-scsi.
The 2.6 kernel supports direct writing to ide CD drives, which
eliminates the need for ide-scsi. ide-scsi has been unmaintained and
marked as deprecated.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James.Bottomley@HansenPartnership.com
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
This makes the top-level function just allocate a single pc entry, and then
pass it down as a pointer to all the helper functions that also need one
of those "struct ide_atapi_pc" things. As far as I can tell, the use of
these things never overlaps each other, BUT I DID NOT CHECK VERY CLOSELY!
So I'm not guaranteeing this is correct, and I don't have the hardware. It
would be good for somebody who knows the code more, and has the hardware,
could please test this?
With this, ide-floppy still has fairly big stack usage, but instead of
idefloppy_ioctl [vmlinux]: 1208
ide_floppy_get_capacity [vmlinux]: 872
idefloppy_release [vmlinux]: 408
idefloppy_open [vmlinux]: 408
where those two first ones are at the very top of the list of stack users
for me, it's now
ide_floppy_get_capacity [vmlinux]: 404
ide_floppy_ioctl [vmlinux]: 364
ie they are still high, but they are no longer at the top.
Borislav: Since ide_floppy_get_capacity is passed as a function pointer to other
parts of the kernel (e.g., block layer) we need that ide_atapi_pc to be created
on stack. Also, redid stack users numbers above. The two functions missing from
Linus' original 'make stackusage' output are due to ide being
rewritten/reorganized atm.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
* Move hack for flush requests from choose_drive() to do_ide_request().
* Add ide_plug_device() helper and convert core IDE code from using
per-hwgroup lock as a request lock to use the ->queue_lock instead.
* Remove no longer needed:
- choose_drive() function
- WAKEUP() macro
- 'sleeping' flag from ide_hwif_t
- 'service_{start,time}' fields from ide_drive_t
This patch results in much simpler and more maintainable code
(besides being a scalability improvement).
v2:
* Fixes/improvements based on review from Elias:
- take as many requests off the queue as possible
- remove now redundant BUG_ON()
Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Add ide_[un]lock_hwgroup() inline helpers for obtaining exclusive
access to the given hwgroup and update the core code accordingly.
[ This change besides making code saner results in more efficient
use of ide_{get,release}_lock(). ]
Cc: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Remove "paranoia" checks for hwgroup->busy from ide_timer_expiry()
and ide_intr(). This is a preparation for future changes.
Cc: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
We now tell block layer that there is still work to do using
blk_plug_device() so hack for IDE Power Management can be removed
(it was buggy for hwgroups having more than 4 devices anyway).
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
* Tell the block layer that we are not done handling requests by using
blk_plug_device() in ide_do_request() (request handling function)
and ide_timer_expiry() (timeout handler) if the queue is not empty.
* Remove optimization which directly calls ide_do_request() for the next
queued command from the ide_intr() (IRQ handler) and ide_timer_expiry().
* Remove no longer needed IRQ masking from ide_do_request() - in case of
IDE ports needing serialization disable_irq_nosync()/enable_irq() was
used for the (possibly shared) IRQ of the other IDE port.
* Put the misplaced comment in the right place in ide_do_request().
* Drop no longer needed 'int masked_irq' argument from ide_do_request().
* Merge ide_do_request() into do_ide_request().
* Remove no longer needed IDE_NO_IRQ define.
While at it:
* Don't use HWGROUP() macro in do_ide_request().
* Use __func__ in ide_intr().
This patch reduces IRQ hadling latency for IDE and improves the system-wide
handling of shared IRQs (which should result in more timeout resistant and
stable IDE systems). It also makes it possible to do some further changes
later (i.e. replace some busy-waiting delays with sleeping equivalents).
v2:
Changes per review from Elias Oltmanns:
- fix wrong goto statement in 'if (startstop == ide_stopped)' block
- use spin_unlock_irq()
- don't use obsolete HWIF() macro
Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
