- 01 Jun, 2012 40 commits
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Doug Ledford authored
Since commit b231cca4 ("message queues: increase range limits") on Oct 18, 2008, calls to mq_open() that did not pass in an attribute struct and expected to get default values for the size of the queue and the max message size now get the system wide maximums instead of hardwired defaults like they used to get. This was uncovered when one of the earlier patches in this patch set increased the default system wide maximums at the same time it increased the hard ceiling on the system wide maximums (a customer specifically needed the hard ceiling brought back up, the new ceiling that commit b231cca4 introduced was too low for their production systems). By increasing the default maximums and not realising they were tied to any attempt to create a message queue without an attribute struct, I had inadvertently made it such that all message queue creation attempts without an attribute struct were failing because the new default maximums would create a queue that exceeded the default rlimit for message queue bytes. As a result, the system wide defaults were brought back down to their previous levels, and the system wide ceilings on the maximums were raised to meet the customer's needs. However, the fact that the no attribute struct behavior of mq_open() could be broken by changing the system wide maximums for message queues was seen as fundamentally broken itself. So we hardwired the no attribute case back like it used to be. But, then we realized that on the very off chance that some piece of software in the wild depended on that behavior, we could work around that issue by adding two new knobs to /proc that allowed setting the defaults for message queues created without an attr struct separately from the system wide maximums. What is not an option IMO is to leave the current behavior in place. No piece of software should ever rely on setting the system wide maximums in order to get a desired message queue. Such a reliance would be so fundamentally multitasking OS unfriendly as to not really be tolerable. Fortunately, we don't know of any software in the wild that uses this except for a regression test program that caught the issue in the first place. If there is though, we have made accommodations with the two new /proc knobs (and that's all the accommodations such fundamentally broken software can be allowed).. This patch: The various defines for minimums and maximums of the sysctl controllable mqueue values are scattered amongst different files and named inconsistently. Move them all into ipc_namespace.h and make them have consistent names. Additionally, make the number of queues per namespace also have a minimum and maximum and use the same sysctl function as the other two settable variables. Signed-off-by:
Doug Ledford <dledford@redhat.com> Acked-by:
Serge E. Hallyn <serue@us.ibm.com> Cc: Amerigo Wang <amwang@redhat.com> Cc: Joe Korty <joe.korty@ccur.com> Cc: Jiri Slaby <jslaby@suse.cz> Acked-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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maximilian attems authored
Add userspace definitions, guard all relevant kernel structures. While at it document stuff and remove now useless userspace hint. It is easy to add the relevant system call to respective libc's, but it seems pointless to have to duplicate the data structures. This is based on the kexec-tools headers, with the exception of just using int on return (succes or failure) and using size_t instead of 'unsigned long int' for the number of segments argument of kexec_load(). Signed-off-by:
maximilian attems <max@stro.at> Cc: Simon Horman <horms@verge.net.au> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Haren Myneni <hbabu@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by:
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Anton Vorontsov authored
Add more comments on clear_tasks_mm_cpumask, plus adds a runtime check: the function is only suitable for offlined CPUs, and if called inappropriately, the kernel should scream aloud. [akpm@linux-foundation.org: tweak comment: s/walks up/walks/, use 80 cols] Suggested-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:
Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by:
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Anton Vorontsov authored
kill_off_processes() might miss a valid process, this is because checking for process->mm is not enough. Process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. To catch this we use find_lock_task_mm(), which walks up all threads and returns an appropriate task (with task lock held). Suggested-by:
Oleg Nesterov <oleg@redhat.com> Signed-off-by:
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Anton Vorontsov authored
Checking for task->mm is dangerous as ->mm might disappear (exit_mm() assigns NULL under task_lock(), so tasklist lock is not enough). We can't use get_task_mm()/mmput() pair as mmput() might sleep, so let's take the task lock while we care about its mm. Note that we should also use find_lock_task_mm() to check all process' threads for a valid mm, but for uml we'll do it in a separate patch. Signed-off-by:
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Anton Vorontsov authored
Traversing the tasks requires holding tasklist_lock, otherwise it is unsafe. p.s. However, I'm not sure that calling os_kill_ptraced_process() in the atomic context is correct. It seem to work, but please take a closer look. Signed-off-by:
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Anton Vorontsov authored
Oleg Nesterov found an interesting deadlock possibility: > sysrq_showregs_othercpus() does smp_call_function(showacpu) > and showacpu() show_stack()->decode_address(). Now suppose that IPI > interrupts the task holding read_lock(tasklist). To fix this, blackfin should not grab the write_ variant of the tasklist lock, read_ one is enough. Suggested-by:
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Anton Vorontsov authored
The patch fixes two problems: 1. Working with task->mm w/o getting mm or grabing the task lock is dangerous as ->mm might disappear (exit_mm() assigns NULL under task_lock(), so tasklist lock is not enough). We can't use get_task_mm()/mmput() pair as mmput() might sleep, so we have to take the task lock while handle its mm. 2. Checking for process->mm is not enough because process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. To catch this we use find_lock_task_mm(), which walks up all threads and returns an appropriate task (with task lock held). Suggested-by:
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Anton Vorontsov authored
Checking for process->mm is not enough because process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. To fix this we would need to use find_lock_task_mm(), which would walk up all threads and returns an appropriate task (with task lock held). clear_tasks_mm_cpumask() has the issue fixed, so let's use it. Suggested-by:
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Anton Vorontsov authored
Current CPU hotplug code has some task->mm handling issues: 1. Working with task->mm w/o getting mm or grabing the task lock is dangerous as ->mm might disappear (exit_mm() assigns NULL under task_lock(), so tasklist lock is not enough). We can't use get_task_mm()/mmput() pair as mmput() might sleep, so we must take the task lock while handle its mm. 2. Checking for process->mm is not enough because process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. To fix this we would need to use find_lock_task_mm(), which would walk up all threads and returns an appropriate task (with task lock held). clear_tasks_mm_cpumask() has all the issues fixed, so let's use it. Suggested-by:
Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by:
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Anton Vorontsov authored
Checking for process->mm is not enough because process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. To fix this we would need to use find_lock_task_mm(), which would walk up all threads and returns an appropriate task (with task lock held). clear_tasks_mm_cpumask() has this issue fixed, so let's use it. Suggested-by:
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Anton Vorontsov authored
Many architectures clear tasks' mm_cpumask like this: read_lock(&tasklist_lock); for_each_process(p) { if (p->mm) cpumask_clear_cpu(cpu, mm_cpumask(p->mm)); } read_unlock(&tasklist_lock); Depending on the context, the code above may have several problems, such as: 1. Working with task->mm w/o getting mm or grabing the task lock is dangerous as ->mm might disappear (exit_mm() assigns NULL under task_lock(), so tasklist lock is not enough). 2. Checking for process->mm is not enough because process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. This patch implements a small helper function that does things correctly, i.e.: 1. We take the task's lock while whe handle its mm (we can't use get_task_mm()/mmput() pair as mmput() might sleep); 2. To catch exited main thread case, we use find_lock_task_mm(), which walks up all threads and returns an appropriate task (with task lock held). Also, Per Peter Zijlstra's idea, now we don't grab tasklist_lock in the new helper, instead we take the rcu read lock. We can do this because the function is called after the cpu is taken down and marked offline, so no new tasks will get this cpu set in their mm mask. Signed-off-by: -
Konstantin Khlebnikov authored
Child should wake up the parent from vfork() only after finishing all operations with shared mm. There is no sense in using CLONE_CHILD_CLEARTID together with CLONE_VFORK, but it looks more accurate now. Signed-off-by:
Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by:
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Konstantin Khlebnikov authored
Currently, nonlinear mappings can not be distinguished from ordinary mappings. This patch adds into /proc/pid/smaps line "Nonlinear: <size> kB", where size is amount of nonlinear ptes in vma, this line appears only if VM_NONLINEAR is set. This information may be useful not only for checkpoint/restore project. Requested by Pavel Emelyanov. Signed-off-by:
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Konstantin Khlebnikov authored
Currently smaps reports migration entries as "swap", as result "swap" can appears in shared mapping. This patch converts migration entries into pages and handles them as usual. Signed-off-by:
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Konstantin Khlebnikov authored
This is an implementation of Andrew's proposal to extend the pagemap file bits to report what is missing about tasks' working set. The problem with the working set detection is multilateral. In the criu (checkpoint/restore) project we dump the tasks' memory into image files and to do it properly we need to detect which pages inside mappings are really in use. The mincore syscall I though could help with this did not. First, it doesn't report swapped pages, thus we cannot find out which parts of anonymous mappings to dump. Next, it does report pages from page cache as present even if they are not mapped, and it doesn't make that has not been cow-ed. Note, that issue with swap pages is critical -- we must dump swap pages to image file. But the issues with file pages are optimization -- we can take all file pages to image, this would be correct, but if we know that a page is not mapped or not cow-ed, we can remove them from dump file. The dump would still be self-consistent, though significantly smaller in size (up to 10 times smaller on real apps). Andrew noticed, that the proc pagemap file solved 2 of 3 above issues -- it reports whether a page is present or swapped and it doesn't report not mapped page cache pages. But, it doesn't distinguish cow-ed file pages from not cow-ed. I would like to make the last unused bit in this file to report whether the page mapped into respective pte is PageAnon or not. [comment stolen from Pavel Emelyanov's v1 patch] Signed-off-by:
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Jan Engelhardt authored
- use int fpr priority and nice, since task_nice()/task_prio() return that - field 24: get_mm_rss() returns unsigned long Signed-off-by:
Jan Engelhardt <jengelh@medozas.de> Signed-off-by:
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Alexey Dobriyan authored
Pass "fd" directly, not via pointer -- one less memory read. Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by:
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Alexey Dobriyan authored
rcu_read_lock()/rcu_read_unlock() is nop for TINY_RCU, but is not a nop for, say, PREEMPT_RCU. proc_fill_cache() is called without RCU lock, there is no need to lock/unlock on error path, simply jump out of the loop. Signed-off-by:
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Cong Wang authored
mm_access() handles this much better, and avoids some race conditions. Signed-off-by:
Cong Wang <xiyou.wangcong@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by:
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Cong Wang authored
mm_for_maps() is a simple wrapper for mm_access(), and the name is misleading, so just remove it and use mm_access() directly. Signed-off-by:
Hugh Dickins <hughd@google.com> Signed-off-by:
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Cong Wang authored
Similar to e268337d ("proc: clean up and fix /proc/<pid>/mem handling"), move the check of permission to open(), this will simplify read() code. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by:
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Tim Bird authored
In embedded systems, sometimes the same program (busybox) is the cause of multiple warnings. Outputting the pid with the program name in the warning printk helps distinguish which instances of a program are using the stack most. This is a small patch, but useful. Signed-off-by:
Tim Bird <tim.bird@am.sony.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by:
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Oleg Nesterov authored
Commit 8f92054e ("CRED: Fix __task_cred()'s lockdep check and banner comment"): add the following validation condition: task->exit_state >= 0 to permit the access if the target task is dead and therefore unable to change its own credentials. OK, but afaics currently this can only help wait_task_zombie() which calls __task_cred() without rcu lock. Remove this validation and change wait_task_zombie() to use task_uid() instead. This means we do rcu_read_lock() only to shut up the lockdep, but we already do the same in, say, wait_task_stopped(). task_is_dead() should die, task->exit_state != 0 means that this task has passed exit_notify(), only do_wait-like code paths should use this. Unfortunately, we can't kill task_is_dead() right now, it has already acquired buggy users in drivers/staging. The fix already exists. Signed-off-by:
"Eric W. Biederman" <ebiederm@xmission.com> Acked-by:
David Howells <dhowells@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: James Morris <jmorris@namei.org> Signed-off-by:
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Randy Dunlap authored
Warning(kernel/kmod.c:419): No description found for parameter 'depth' Signed-off-by:
Randy Dunlap <rdunlap@xenotime.net> Signed-off-by:
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Boaz Harrosh authored
If we move call_usermodehelper_fns() to kmod.c file and EXPORT_SYMBOL it we can avoid exporting all it's helper functions: call_usermodehelper_setup call_usermodehelper_setfns call_usermodehelper_exec And make all of them static to kmod.c Since the optimizer will see all these as a single call site it will inline them inside call_usermodehelper_fns(). So we loose the call to _fns but gain 3 calls to the helpers. (Not that it matters) Signed-off-by:
Boaz Harrosh <bharrosh@panasas.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:
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Boaz Harrosh authored
Both kernel/sys.c && security/keys/request_key.c where inlining the exact same code as call_usermodehelper_fns(); So simply convert these sites to directly use call_usermodehelper_fns(). Signed-off-by:
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Boaz Harrosh authored
call_usermodehelper_freeinfo() is not used outside of kmod.c. So unexport it, and make it static to kmod.c Signed-off-by:
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Namjae Jeon authored
If an application tries to lookup (opendir/readdir/stat) 5000 files on a fatfs USB device and the device is unplugged, many message occur, shown below. This makes the application slow. So use the new fat_msg_ratelimit() decrease the messaging rate. #> ./file_lookup_testcase ./files_directory/ usb 2-1.4: USB disconnect, device number 4 FAT-fs (sda1): FAT read failed (blocknr 2631) FAT-fs (sda1): Directory bread(block 396816) failed FAT-fs (sda1): Directory bread(block 396817) failed FAT-fs (sda1): Directory bread(block 396818) failed FAT-fs (sda1): Directory bread(block 396819) failed FAT-fs (sda1): Directory bread(block 396820) failed FAT-fs (sda1): Directory bread(block 396821) failed FAT-fs (sda1): Directory bread(block 396822) failed FAT-fs (sda1): Directory bread(block 396823) failed FAT-fs (sda1): Directory bread(block 406824) failed FAT-fs (sda1): Directory bread(block 406825) failed FAT-fs (sda1): Directory bread(block 406826) failed FAT-fs (sda1): Directory bread(block 406827) failed FAT-fs (sda1): Directory bread(block 406828) failed FAT-fs (sda1): Directory bread(block 406829) failed FAT-fs (sda1): Directory bread(block 406830) failed FAT-fs (sda1): Directory bread(block 406831) failed FAT-fs (sda1): Directory bread(block 417696) failed FAT-fs (sda1): Directory bread(block 417697) failed FAT-fs (sda1): Directory bread(block 417698) failed FAT-fs (sda1): Directory bread(block 417699) failed FAT-fs (sda1): Directory bread(block 417700) failed FAT-fs (sda1): Directory bread(block 417701) failed FAT-fs (sda1): Directory bread(block 417702) failed FAT-fs (sda1): Directory bread(block 417703) failed FAT-fs (sda1): FAT read failed (blocknr 2631) FAT-fs (sda1): Directory bread(block 396816) failed FAT-fs (sda1): Directory bread(block 396817) failed FAT-fs (sda1): Directory bread(block 396818) failed FAT-fs (sda1): Directory bread(block 396819) failed FAT-fs (sda1): Directory bread(block 396820) failed FAT-fs (sda1): Directory bread(block 396821) failed Signed-off-by:
Namjae Jeon <linkinjeon@gmail.com> Signed-off-by:
Amit Sahrawat <amit.sahrawat83@gmail.com> Acked-by:
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by:
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Namjae Jeon authored
Add a fat_msg_ratelimit() to limit the message generation rate. Signed-off-by:
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Artem Bityutskiy authored
Currently FAT file-system maps the VFS "superblock" abstraction to the FSINFO block. The FSINFO block contains non-essential data about the amount of free clusters and the next free cluster. FAT file-system can always find out this information by scanning the FAT table, but having it in the FSINFO block may speed things up sometimes. So FAT file-system relies on the VFS superblock write-out services to make sure the FSINFO block is written out to the media from time to time. The whole "superblock write-out" VFS infrastructure is served by the 'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds and writes out all dirty superblock using the '->write_super()' call-back. But the problem with this thread is that it wastes power by waking up the system every 5 seconds no matter what. So we want to kill it completely and thus, we need to make file-systems to stop using the '->write_super' VFS service, and then remove it together with the kernel thread. This patch switches the FAT FSINFO block management from '->write_super()'/'->s_dirt' to 'fsinfo_inode'/'->write_inode'. Now, instead of setting the 's_dirt' flag, we just mark the special 'fsinfo_inode' inode as dirty and let VFS invoke the '->write_inode' call-back when needed, where we write-out the FSINFO block. This patch also makes sure we do not mark the 'fsinfo_inode' inode as dirty if we are not FAT32 (FAT16 and FAT12 do not have the FSINFO block) or if we are in R/O mode. As a bonus, we can also remove the '->sync_fs()' and '->write_super()' FAT call-back function because they become unneeded. Signed-off-by:
Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Artem Bityutskiy authored
Preparation for further changes. It touches few functions in fatent.c and prevents them from marking the superblock as dirty unnecessarily often. Namely, instead of marking it as dirty in the internal tight loops - do it only once at the end of the functions. And instead of marking it as dirty while holding the FAT table lock, do it outside the lock. The reason for this patch is that marking the superblock as dirty will soon become a little bit heavier operation, so it is cleaner to do this only when it is necessary. Signed-off-by:
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Artem Bityutskiy authored
A preparation patch which introduces a 'mark_fsinfo_dirty()' helper function which just sets the 's_dirt' flag to 1 so far. I'll add more code to this helper later, so I do not mark it as 'inline'. Signed-off-by:
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Artem Bityutskiy authored
This is patchset makes fatfs stop using the VFS '->write_super()' method for writing out the FSINFO block. The final goal is to get rid of the 'sync_supers()' kernel thread. This kernel thread wakes up every 5 seconds (by default) and calls '->write_super()' for all mounted file-systems. And the bad thing is that this is done even if all the superblocks are clean. Moreover, some file-systems do not even need this end they do not register the '->write_super()' method at all (e.g., btrfs). So 'sync_supers()' most often just generates useless wake-ups and wastes power. I am trying to make all file-systems independent of '->write_super()' and plan to remove 'sync_supers()' and '->write_super' completely once there are no more users. The '->write_supers()' method is mostly used by baroque file-systems like hfs, udf, etc. Modern file-systems like btrfs and xfs do not use it. This justifies removing this stuff from VFS completely and make every FS self-manage own superblock. Tested with xfstests. This patch: Preparation for further changes. It introduces a special inode ('fsinfo_inode') in FAT file-system which we'll later use for managing the FSINFO block. Note, this there is already one special inode ('fat_inode') which is used for managing the FAT tables. Introduce new 'MSDOS_FSINFO_INO' constant for this special inode. It is safe to do because FAT file-system does not store inode numbers on the media but generates them run-time. I've also cleaned up the comment to existing 'MSDOS_ROOT_INO' constant, while on it. Signed-off-by: -
Dan Carpenter authored
The PRINTK() macro isn't really used. Let's just remove it because it is ugly and out of date. Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Signed-off-by:
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Ryusuke Konishi authored
There are two cases that the cache flush is needed to avoid data loss against unexpected hang or power failure. One is sync file function (i.e. nilfs_sync_file) and another is checkpointing ioctl. This issues a cache flush request to device for such cases if barrier mount option is enabled, and makes sure data really is on persistent storage on their completion. Signed-off-by:
Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by:
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Will Deacon authored
As described in commit 07d106d0 ("vfs: fix up ENOIOCTLCMD error handling"), drivers should return -ENOIOCTLCMD if they receive an ioctl command which they don't understand. Doing so will result in -ENOTTY being returned to userspace, which matches the behaviour of the compat layer if it fails to translate an ioctl command. This patch fixes the pipe ioctl to return -ENOIOCTLCMD instead of -EINVAL when passed an unknown ioctl command. Signed-off-by:
Will Deacon <will.deacon@arm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Acked-by:
Alan Cox <alan@linux.intel.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by:
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H Hartley Sweeten authored
The init/mount.o source files produce a number of sparse warnings of the type: warning: incorrect type in argument 1 (different address spaces) expected char [noderef] <asn:1>*dev_name got char *name This is due to the syscalls expecting some of the arguments to be user pointers but they are being passed as kernel pointers. This is harmless but adds a lot of noise to a sparse build. To limit the noise just disable the sparse checking in the relevant source files, but still display a warning so that the user knows this has been done. Since the sparse checking has been disabled we can also remove the __user __force casts that are scattered thru the source. Signed-off-by:
H Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by:
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Joe Perches authored
Suggest the shorter pr_<level> instead of printk(KERN_<LEVEL>. Prefer to use pr_<level> over bare printks. Prefer to use pr_warn over pr_warning. Signed-off-by:
Joe Perches <joe@perches.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by:
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Eric Nelson authored
Requires --strict option during invocation: ~/linux$ scripts/checkpatch --strict foo.patch This tests for a bad habits of mine like this: return 0 ; Note that it does allow a special case of a bare semicolon for empty loops: while (foo()) ; Signed-off-by:
Eric Nelson <eric.nelson@boundarydevices.com> Cc: Andy Whitcroft <apw@canonical.com> Cc: Joe Perches <joe@perches.com> Signed-off-by:
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