Sap Kernel Path

[Mandy Geise]

Myfirst guess is that you haven't installed the headers. You need to install the appropriate linux-headers package. Most likely, you need to install linux-headers-generic. However, if if you're running some kernel other than linux-generic, install the linux-headers package for that kernel.

How do I add an include path for kernel module makefile? I want to include "test_kernel.h" in test_module.c. the "test_kernel.h" resides in other directory "inc"I tried in the following solution in my Makefile but it does not work:

I checked the Notebook Github repo, saw the note that active development is all in JupyterLab, so I tried installing that and running it, but I see the same behavior: the path for shell commands is unaffected by the active kernel. I have less experience with JupyterLab than the plain Notebook server, though, so I might be overlooking some step there.

I thought I had installed all the correct files for compiling kernel modules.

I am trying to install VMware tools in a virtual machine running SUSE 11.3 as the guest OS, I just want a running compiler with all the necessaries.

If I recall this correctly, modprobe would search for modules in the main module directory, and also in the extramodules directory. Somehow I can't get it to pay attention to the extramodules directory any more ... what am I doing wrong?

If understand the man page correctly, this causes depmod to compare the date on the module with the date on the dependencies file. So if my kernel module was built before (but installed after) the depedencies file was last updated, we're out of luck, no?

You could override the hook in /etc/pacman.d/hooks/ with a version that does not use --quick as a test.

If that works as expected then somehow the modules mtime is older than that of the modules.dep.

I am working in RHEL 7 and I need to install the Nvidia driver for my GPU. I know I have downloaded the right driver from the Nvidia website. I have also installed the linux kernel packages and those are located in /usr as in /usr/include/linux/kernel.h

As the name of the option suggests, it's supposed to be pointed at a directory hierarchy whose structure matches the root directory of a standard Linux kernel source tree. It will have its own include sub-directory, exactly as the installer is expecting.

As number of components in path increases possible

combinations also increases. So I want to covert above

paths in a unique path such as long path. But I want

to convert given path in to long path in kernel mode.

I doubt there is an API like GetLongPathName in the kernel.

You would have do what GetLongPathName does!

I believe it will go component by component and get the corresponding long path names.

(You can use Procmon to understand this)

I am surprised one can allocate a callback object and use it for purposes like these. My understanding was that Mini-Filters can allocate callbacks for purposes of doing FltPerformAsynchronousIo and FltPerformSynchronousIo requests.

Thanks for the solution. I have done it using FltGetFileNameInformation.

But the problem is that I have to allocate callback data using

FltAllocateCallbackData as I am not in any minifilter callback routine.

So I dont have instance which is compalsory parameter for

FltAllocateCallbackData. Is there any other way?

I am in Image load notification routine, and I want to compair the path

with a spacific file. As path in this notification routine can be any thing

as I explained in my first post in this thread we need to convert it in to

long path and then compair.

-----Original Message-----

From: xx...@lists.osr.com

[mailto:xx...@lists.osr.com] On Behalf Of

xx...@yahoo.com

Sent: Sunday, December 06, 2009 11:15 PM

To: Windows File Systems Devs Interest List

Subject: RE:[ntfsd] How to convert given path to long path in kernel mode?

I am in Image load notification routine, and I want to compair the path with

a spacific file. As path in this notification routine can be any thing as I

explained in my first post in this thread we need to convert it in to long

path and then compair.

Note that the official docs refer to cross compile from an Ubuntu host PC, but you can also natively compile from the Xavier. Instructions vary slightly depending on which you do. You might find this of use, but be careful to note this is old and for a TX2:

-wifi-support/63839/2

Just ask again if you run into something you want more information about. Here is something in general about the world of building kernels, modules, and device trees (which was written for a TX1, but applies to anything):

-kernel/77995/18

If your kernel source is on the Xavier, then this is where you run the commands with make in their simplest form. If your kernel source is on the host PC, then you will need to also add some options for the cross compiler tool chain location and architecuture (if you see ARCH=..., then you are cross compiling, and there would also be a CROSS_COMPILE=...). Most of the instructions you see in the official documents are for cross compile from a PC. If you have kernel source on the Xavier, then it simplifies instructions.

One reason why there is a drive to provide some device tree setup in earlier boot stages is security, e.g., validating boot components are authentic before using them. If not for this I think device tree and bootloaders would be less complicated.

A pathname that contains at least one non- character andthat ends with one or more trailing characters shall notbe resolved successfully unless the last pathname component beforethe trailing characters names an existing directory or adirectory entry that is to be created for a directory immediatelyafter the pathname is resolved.

The dcache has a number of uses apart from accelerating lookup. Onethat will be particularly relevant is that it is closely integratedwith the mount table that records which filesystem is mounted where.What the mount table actually stores is which dentry is mounted on topof which other dentry.

The association between a dentry and its inode is fairly permanent.For example, when a file is renamed, the dentry and inode movetogether to the new location. When a file is created the dentry willinitially be negative (i.e. d_inode is NULL), and will be assignedto the new inode as part of the act of creation.

When a file is deleted, this can be reflected in the cache either bysetting d_inode to NULL, or by removing it from the hash table(described shortly) used to look up the name in the parent directory.If the dentry is still in use the second option is used as it isperfectly legal to keep using an open file after it has been deletedand having the dentry around helps. If the dentry is not otherwise inuse (i.e. if the refcount in d_lockref is one), only then willd_inode be set to NULL. Doing it this way is more efficient for avery common case.

d_lock is a synonym for the spinlock that is part of d_lockref above.For our purposes, holding this lock protects against the dentry beingrenamed or unlinked. In particular, its parent (d_parent), and itsname (d_name) cannot be changed, and it cannot be removed from thedentry hash table.

Looking up a given name in a given directory involves computing a hashfrom the two values (the name and the dentry of the directory),accessing that slot in a hash table, and searching the linked listthat is found there.

When a dentry is renamed, the name and the parent dentry can bothchange so the hash will almost certainly change too. This would move thedentry to a different chain in the hash table. If a filename searchhappened to be looking at a dentry that was moved in this way,it might end up continuing the search down the wrong chain,and so miss out on part of the correct chain.

The name-lookup process (d_lookup()) does not try to prevent thisfrom happening, but only to detect when it happens.rename_lock is a seqlock that is updated whenever any dentry isrenamed. If d_lookup finds that a rename happened while itunsuccessfully scanned a chain in the hash table, it simply triesagain.

i_rwsem is a read/write semaphore that serializes all changes to a particulardirectory. This ensures that, for example, an unlink() and a rename()cannot both happen at the same time. It also keeps the directorystable while the filesystem is asked to look up a name that is notcurrently in the dcache or, optionally, when the list of entries in adirectory is being retrieved with readdir().

This has a complementary role to that of d_lock: i_rwsem on adirectory protects all of the names in that directory, while d_lockon a name protects just one name in a directory. Most changes to thedcache hold i_rwsem on the relevant directory inode and briefly taked_lock on one or more the dentries while the change happens. Oneexception is when idle dentries are removed from the dcache due tomemory pressure. This uses d_lock, but i_rwsem plays no role.

Secondly, when pathname lookup reaches the final component, it willsometimes need to take an exclusive lock on i_rwsem before performing the last lookup sothat the required exclusion can be achieved. How path lookup choosesto take, or not take, i_rwsem is one of theissues addressed in a subsequent section.

If two threads attempt to look up the same name at the same time - aname that is not yet in the dcache - the shared lock on i_rwsem willnot prevent them both adding new dentries with the same name. As thiswould result in confusion an extra level of interlocking is used,based around a secondary hash table (in_lookup_hashtable) and aper-dentry flag bit (DCACHE_PAR_LOOKUP).

To add a new dentry to the cache while only holding a shared lock oni_rwsem, a thread must call d_alloc_parallel(). This allocates adentry, stores the required name and parent in it, checks if thereis already a matching dentry in the primary or secondary hashtables, and if not, stores the newly allocated dentry in the secondaryhash table, with DCACHE_PAR_LOOKUP set.

If a matching dentry was found in the primary hash table then that isreturned and the caller can know that it lost a race with some otherthread adding the entry. If no matching dentry is found in eithercache, the newly allocated dentry is returned and the caller candetect this from the presence of DCACHE_PAR_LOOKUP. In this case itknows that it has won any race and now is responsible for asking thefilesystem to perform the lookup and find the matching inode. Whenthe lookup is complete, it must call d_lookup_done() which clearsthe flag and does some other house keeping, including removing thedentry from the secondary hash table - it will normally have beenadded to the primary hash table already. Note that a structwaitqueue_head is passed to d_alloc_parallel(), andd_lookup_done() must be called while this waitqueue_head is stillin scope.

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