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This removes the retry-based AIO infrastructure now that nothing in tree
is using it.
We want to remove retry-based AIO because it is fundemantally unsafe.
It retries IO submission from a kernel thread that has only assumed the
mm of the submitting task. All other task_struct references in the IO
submission path will see the kernel thread, not the submitting task.
This design flaw means that nothing of any meaningful complexity can use
retry-based AIO.
This removes all the code and data associated with the retry machinery.
The most significant benefit of this is the removal of the locking
around the unused run list in the submission path.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Kent Overstreet <koverstreet@google.com>
Signed-off-by: Zach Brown <zab@redhat.com>
Cc: Zach Brown <zab@redhat.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Reviewed-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
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NFS optimizes away d_revalidates for last component of open. This means that
open itself can find the dentry stale.
This patch allows the filesystem to return EOPENSTALE and the VFS will retry the
lookup on just the last component if possible.
If the lookup was done using RCU mode, including the last component, then this
is not possible since the parent dentry is lost. In this case fall back to
non-RCU lookup. Currently this is not used since NFS will always leave RCU
mode.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Allow drivers to report at probe time that they cannot get all the resources
required by the device, and should be retried at a later time.
This should completely solve the problem of getting devices
initialized in the right order. Right now this is mostly handled by
mucking about with initcall ordering which is a complete hack, and
doesn't even remotely handle the case where device drivers are in
modules. This approach completely sidesteps the issues by allowing
driver registration to occur in any order, and any driver can request
to be retried after a few more other drivers get probed.
v4: - Integrate Manjunath's addition of a separate workqueue
- Change -EAGAIN to -EPROBE_DEFER for drivers to trigger deferral
- Update comment blocks to reflect how the code really works
v3: - Hold off workqueue scheduling until late_initcall so that the bulk
of driver probes are complete before we start retrying deferred devices.
- Tested with simple use cases. Still needs more testing though.
Using it to get rid of the gpio early_initcall madness, or to replace
the ASoC internal probe deferral code would be ideal.
v2: - added locking so it should no longer be utterly broken in that regard
- remove device from deferred list at device_del time.
- Still completely untested with any real use case, but has been
boot tested.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dilan Lee <dilee@nvidia.com>
Cc: Manjunath GKondaiah <manjunath.gkondaiah@linaro.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: David Daney <david.daney@cavium.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add comment for errnos related to restart syscall to avoid the leakage of
them to user programs.
Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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From: Daniel McNeil <daniel@osdl.org>
From: Chris Mason <mason@suse.com>
AIO: retry infrastructure fixes and enhancements
Reorganises, comments and fixes the AIO retry logic. Fixes
and enhancements include:
- Split iocb setup and execution in io_submit
(also fixes io_submit error reporting)
- Use aio workqueue instead of keventd for retries
- Default high level retry methods
- Subtle use_mm/unuse_mm fix
- Code commenting
- Fix aio process hang on EINVAL (Daniel McNeil)
- Hold the context lock across unuse_mm
- Acquire task_lock in use_mm()
- Allow fops to override the retry method with their own
- Elevated ref count for AIO retries (Daniel McNeil)
- set_fs needed when calling use_mm
- Flush workqueue on __put_ioctx (Chris Mason)
- Fix io_cancel to work with retries (Chris Mason)
- Read-immediate option for socket/pipe retry support
Note on default high-level retry methods support
================================================
High-level retry methods allows an AIO request to be executed as a series of
non-blocking iterations, where each iteration retries the remaining part of
the request from where the last iteration left off, by reissuing the
corresponding AIO fop routine with modified arguments representing the
remaining I/O. The retries are "kicked" via the AIO waitqueue callback
aio_wake_function() which replaces the default wait queue entry used for
blocking waits.
The high level retry infrastructure is responsible for running the
iterations in the mm context (address space) of the caller, and ensures that
only one retry instance is active at a given time, thus relieving the fops
themselves from having to deal with potential races of that sort.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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handling.
Update x86 to use the new infrastructure.
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