Re: Should I return NOTIFY_DONE always from restart handler?

Hello, I believe you'll break the "chain" if you return an error. You might have registered as the last one so probably nothing would break but if someone registers on the notifier after your module did then that won't receive the notification if you throw an error and break the chain. Regards,

Re: How to setup network connection for initramfs running in QEMU?

Hi Douglas, Do you've /etc/hosts ? Have you tried giving the loopback address in that file? Just check any /etc/hosts file from another distribution and hack on it to at least have loopback address pinged. Then we'll try to fix machine to machine ping. (Tun-tap? Not sure really.) On

Re: My kernel patch was rejected with comments

On Wed, Mar 22, 2017 at 5:09 PM, Prasant J wrote: > On Wed, Mar 22, 2017 at 4:02 PM, Tobin C. Harding wrote: >> On Wed, Mar 22, 2017 at 12:24:47PM +0530, Prasant J wrote: >>> Hi, >>> >>> I submitted a kernel patch and it was rejected with comments from >>>

Re: simple block device - request processing in threads

On Friday, March 3, 2017, Andras Pal wrote: > Dear All, > > with some experience in low-level C programming, I started to develop a > kernel module which allows I2C slave EEPROM-alike devices (EEPROMs, FRAMs, > BBRAMs, etc) to be accessed as block devices. Since the i/o

Re: How do you generate the config file?

On Mon, Jan 30, 2017 at 6:04 AM, Abel wrote: > > Yes, similar procedure I've followed. > I didn't forget step 4. I actually always did `sudo make install_modules`. > I'm not sure what's going on. > > Maybe it has sth to do with Ubuntu, that's why specifically mention I was >

Re: Fwd: Need some help regarding write_begin, write_end and writepage(s).

Hi Valdis, On Wed, Jan 4, 2017 at 12:58 AM, <valdis.kletni...@vt.edu> wrote: > On Thu, 29 Dec 2016 12:35:52 +0530, Pranay Srivastava said: >> Hello, >> >> I'm trying to understand the write_begin, write_end and writepages / >> writepage call >> seque

Fwd: Need some help regarding write_begin, write_end and writepage(s).

Hello, I'm trying to understand the write_begin, write_end and writepages / writepage call sequence by having a small file system coded myself. I'm not using block_write_begin / block_write_end also not using mpage_writepages as well. The issue however is that apart from write_begin and

Re: Understanding Platform devices and platform drivers.

On Mon, Nov 7, 2016 at 12:43 PM, Madhu K wrote: > Hi All, > > I am trying to understand the concept of platform device and platform > driver, my very basic question is that, the devices and data which is > present in device tree represents platform devices and platform data?

Re: Kernel Panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Hi On Tuesday, August 16, 2016, shobhit bhadani wrote: > Hi, > > I am new to kernel. > What does this issue mean "not syncing: Attempted to kill init! "? > > Is this a user space issue? > > 17:10:09.0464-04:00 - Kernel panic - not syncing: Attempted to kill init!

Re: Help understanding block layer sample in LDD3

On Fri, Jul 29, 2016 at 4:15 PM, François <f...@code-libre.org> wrote: > On Fri, Jul 29, 2016 at 03:58:28PM +0530, Pranay Srivastava wrote: >> >> I don't see req->buffer. Which version you are using? > > You're absolutely right. Both [1] and [2] seems to be outda

Re: doubt on schedule_work() - work task getting scheduled lately

On Fri, Jul 29, 2016 at 4:02 PM, Muni Sekhar wrote: > Hi All, > > I have a doubt regarding the workqueue scheduling. > > I am using the workqueue for processing the Rx Interrupt data. I am > calling schedule_work() on receiving the Rx interrupt from hardware. > > I

Re: Help understanding block layer sample in LDD3

On Fri, Jul 29, 2016 at 3:14 PM, François wrote: > Hi there, > > I've been reading LDD3's chapter 16 on block devices a few times, and have > made toys > block layers module. Now I've been looking at the up-to-date examples > provided by martinez javier[1], > but still

Re: Linux Kernel | Process Open Files

On Thu, Jun 23, 2016 at 11:55 AM, Shahab Khalid wrote: > Hi all, > > I am trying to get process open files of active processes. I am reading > linux dump. I am able to get actives process. I am trying to reach d_name in > dentry structure but unfortunately the I am receiving

Re: Use of list_head struct

On Fri, Jun 17, 2016 at 3:41 PM, Martin Houry wrote: > Hello mailing list! > I've read some code in the NFS4.1 client. I have trouble to access > variables in a list_head. > > So I have : > (include/linux/sunrpc/xprt.h line 168) > struct rpc_xprt{ > . > . > >

Re: system call

On Sat, Apr 9, 2016 at 8:11 PM, Nitin Varyani <varyani.nit...@gmail.com> wrote: > I am using Ubuntu > > On Sat, Apr 9, 2016 at 8:04 PM, Pranay Srivastava <pran...@gmail.com> wrote: >> >> On Sat, Apr 9, 2016 at 7:51 PM, Nitin Varyani <varyani.nit...@gmail.com>

Re: system call

> > After then I restarted my system and booted linux 3.5.4. But it was stuck > half way. > > On Sat, Apr 9, 2016 at 7:39 PM, Pranay Srivastava <pran...@gmail.com> wrote: >> >> Hi Nitin >> >> On Sat, Apr 9, 2016 at 5:03 PM, Nitin Varyani <varyani.nit.

Re: system call

is displayed on booting. I don't think this is related to the changes you made. I would advise you just build the sources for your distro and try to get to boot the kernel you compiled. Perhaps some steps you might have missed specific to your distro? > > > On Thu, Apr 7, 2016 at 1:08 PM,

Re: system call

Nitin On Thu, Apr 7, 2016 at 11:53 AM, Nitin Varyani wrote: > > Hi, > I want to implement a system call as explained in Linux kernel > development by Robert Love. > > He does three things > adding entry to entry.S > adding entry to asm/unistd.h > and adding the

Re: Attach my own pid

ernel is doing. Like for example nfs, translates the inode to a file handle internally but that framework is independent of what happens on both nodes. > > On Mon, Mar 21, 2016 at 4:18 PM, Pranay Srivastava <pran...@gmail.com> > wrote: >> >> Nitin, >> >> >

Re: Correctly locking a Block Device Request Handler

Hi On Mon, Nov 16, 2015 at 10:02 PM, Marcel Müller wrote: > Hello everyone, > > I'm currently writing a block device driver and got stuck at trying to > understand how to correctly handle the locking > in the reqfn one passes to `blk_init_queue`. > > My code looks like this:

Re: Get user stackpointer from task_struct

On Wed, Nov 4, 2015 at 2:54 AM, Shirish Gajera wrote: > Hi, > > I have kcore and I want to get userspace backtrace from kcore. I looked at > some macro but still this is just giving me kernel backtrace only. What I > want is userspace backtrace. > > Good news is I have

Re: How to get user level stack trace of an application from system crash

On Tue, Oct 6, 2015 at 11:23 AM, Shailendra Rana wrote: > Hi, > > I have an application which traps file events using fanotify, process > these events and gives a verdict to fanotify whether access to a file > is allowed or not. However, in some cases the verdict

Re: Unable to get stmmac driver of Altera Cyclone V to support MTU9000

Hi Teoh, On Mon, Sep 28, 2015 at 7:17 AM, Teoh Choon Zone wrote: >> When you set the MTU, does it show up as set if you do 'ifconfig eth2' >> or whatever it is? > I can see it being set successfully. > > >> In what way *exactly* does the ping "just won't start"? Any

Re: mmap - post/pre actions

Hi Ran On Wed, Sep 16, 2015 at 1:10 AM, Ran Shalit wrote: > Hello, > > I need to implement mmap for non-volatile memory chip (NVRAM). > I already did something simple, but now I understand that it is not complete: > The nvram need to be unlock and locked after finishing the

Re: How to properly unregister LED class devices?

On Sun, Sep 6, 2015 at 11:18 PM, Clément Vuchener wrote: > Hello, > > I am trying to write a driver that uses LED class devices using works for > setting the LED brightness but I am not sure of how to unregister the devices. > > I have been using code like this: >

Re: How to properly unregister LED class devices?

On Mon, Sep 7, 2015 at 5:53 PM, Clément Vuchener <clement.vuche...@gmail.com> wrote: > On Mon, Sep 07, 2015 at 05:17:09PM +0530, Pranay Srivastava wrote: >> On Mon, Sep 7, 2015 at 4:58 PM, Jacek Anaszewski >> <j.anaszew...@samsung.com> wrote: >> > Hi Clément, &

Re: How to properly unregister LED class devices?

On Mon, Sep 7, 2015 at 4:58 PM, Jacek Anaszewski <j.anaszew...@samsung.com> wrote: > Hi Clément, > > > On 09/07/2015 11:05 AM, Clément Vuchener wrote: >> >> On Mon, Sep 07, 2015 at 12:08:17PM +0530, Pranay Srivastava wrote: >>> >>> O

Re: signals handling in kernel

intricacies, so thought of this exercise. Is it possible ? Have you checked how signals are sent and handled within kernel? On Fri, Aug 14, 2015 at 6:10 PM, Pranay Srivastava pran...@gmail.com wrote: On Fri, Aug 14, 2015 at 5:38 PM, KASHISH BHATIA kashish.bhatia1...@gmail.com wrote

Re: signals handling in kernel

On Fri, Aug 14, 2015 at 5:38 PM, KASHISH BHATIA kashish.bhatia1...@gmail.com wrote: Is it possible to send signal from one kthread to another kthread using signal apis defined in signal.h and signal.c. Also I want to override the default behavior of a signal handler. How can I achieve this ?

Re: Do you know the bug of EXPORT_SYMBOL()

On Fri, Jul 24, 2015 at 11:19 AM, Navy nav...@126.com wrote: Hi To my understanding, EXPORT_SYMBOL() is used to export a symbol in kernel/modules. The the address of the all sysbols is in /proc/kallsyms. Only symbols exported by EXPORT_SYMBOL() is listed its CRC information in Module.symvers.

Re: HOSTAPD Error log

Hi Amit On Thu, Jul 23, 2015 at 11:09 PM, valdis.kletni...@vt.edu wrote: On Thu, 23 Jul 2015 12:31:18 +0530, Amit Gupta said: Configuration file: /etc/hostapd.conf [ 199.672712] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready Failed to update rate sets in kernel module [ 199.687566]

Re: Scull Driver - Read

mean kernel will read from that. I hope this clears it. if(err) return -EFAULT; Thanks Regards On 20 March 2015 at 12:36, sahil aggarwal sahil.ag...@gmail.com wrote: Hi Pranay Well explained. Thank you. On 20 March 2015 at 11:46, Pranay Srivastava pran...@gmail.com wrote: Hi

Re: Scull Driver - Read

) _IOC_WRITE) err = !access_ok(VERIFY_READ, (void __user*)arg, _IOC_SIZE(cmd)); if(err) return -EFAULT; Thanks Regards On 20 March 2015 at 12:36, sahil aggarwal sahil.ag...@gmail.com wrote: Hi Pranay Well explained. Thank you. On 20 March 2015 at 11:46, Pranay Srivastava

Re: Scull Driver - Read

Hi Sahil On Sun, Mar 15, 2015 at 10:17 AM, sahil aggarwal sahil.ag...@gmail.com wrote: hi all, Going through scull driver code, i see read function reads only till end of 1 quantum, so do kernel call read multiple times if count from q_pos exceeds quantum size limit.? Ref: ldd3.

Re: Are there any API's to create ring buffers easily in kernel?

Hi Manty On Mon, Mar 2, 2015 at 3:24 AM, manty kuma mantyk...@gmail.com wrote: Hi, Are there any ready-to-use API's in kernel to allocate a ring buffer and give some prints into it (I don't want to corrupt kernel log)? Have you seen circ_buff? Documentation/circular-buffers.txt Best

Re: sk_wait_data

Hi On Thu, Feb 19, 2015 at 3:45 PM, Grzegorz Dwornicki gd1...@gmail.com wrote: Hello Proces have a established tcp socket. It calls sys_revcmsg on that socket. That function goes all the way to tcp_recvmsg function. Function tcp_recvmsg.c (defined in net/ipv4/tcp.c) blocks it self on

Re: workqueues - how to use them correctly

On Tue, Feb 10, 2015 at 1:50 AM, Roshan A roshan@gmail.com wrote: hi all, My question is regarding the correct use of workqueues. I have a driver which queues a work item in the interrupt handler. The bottom half function ( the workitem -function ) does have proper locking ( mutex ) in

Re: Block Device Driver Tutorial

Hi Gunjan On Sun, Jan 25, 2015 at 5:13 AM, Gunjan Mehta gunjanmeht...@gmail.com wrote: Any online links for study and understanding? Or any other institute? On Wed, Jan 21, 2015 at 9:42 PM, Saket Sinha saket.sinh...@gmail.com wrote: Hi, I would refer Anil Pugalia from

Re: Shared mapping

Hi Riya, On Mon, Jan 12, 2015 at 2:08 AM, riya khanna riyakhanna1...@gmail.com wrote: Hi, Is there a way, w.r.t memory contents, to make a process B see what process A sees through shared memory mappings? Suppose Process A has mapped a device file (say F) at address 0x in its

Re: Shared mapping

Hi Riya, On Mon, Jan 12, 2015 at 10:01 AM, riya khanna riyakhanna1...@gmail.com wrote: With shared memory mappings, once A and B both map the same memory address/file they see the same contents A [0x] - maps - to - [0x] B [0x] - maps - to - [0x] However, if A

Re: Understanding of write file operation in char driver

Hi Prasad, On Sat, Jan 3, 2015 at 9:23 PM, me storage me.storage...@gmail.com wrote: Hi, Thanks Valdis for your nice explanation. After practising i got another doubt if read from my driver as below cat /dev/myDev for this how many times read function will call because some times it is

Re: Fwd: Query about /proc/meminfo

On 13-Dec-2014 2:27 AM, PRAJAPATI MEHUL mehulprajapati2...@gmail.com wrote: Hi, -I am currently working on one embedded development board. -I have ported 3.0.31 kernel with my personal patches on it. -When I am trying to insert my module, it fails to allocate 4MB memory using kmalloc.

Re: Userspace agent crash and kernel module

Hi Kevin, Request you not to top post :-) . On Tue, Nov 18, 2014 at 10:15 AM, Pranay Srivastava pran...@gmail.com wrote: Hi Kevin On Tue, Nov 18, 2014 at 1:19 PM, Kevin Wilson wkev...@gmail.com wrote: Hi, I want to write a kernel module which interacts with a userspace daemon

Re: Userspace agent crash and kernel module

Hi Kevin On Tue, Nov 18, 2014 at 1:19 PM, Kevin Wilson wkev...@gmail.com wrote: Hi, I want to write a kernel module which interacts with a userspace daemon. There are cases when the userspace daemon can terminate by some signals. There are also cases where the userspace daemon can crash

Re: mapping of inode and file structure in Open System call

Hi Lokesh On Wed, Nov 12, 2014 at 6:42 PM, lokesh kumar lokeshkumar@gmail.com wrote: Hi, I have a question regarding open systemcall open(dev_name, O_RDWR, 0)--userspace suppose devname is /dev/my_device Now when we look into open file operation, we have prototype int (*open)

Re: broken network connection

Hi On Fri, Nov 7, 2014 at 2:37 AM, Grzegorz Dwornicki gd1...@gmail.com wrote: Hi I have a big interest in how kernel handles this situaction. Lets assume that we have two hosts: host 1 and host 2 and on host 1 I have started this command: nc -l -p on host 2 I have started this

Re: How can I wake up one process from the wait queue?

Hi You got to use exclusive wait queues here. Needs a bit more lines but you can specify exactly how many tasks you want woken up. You should be able to look it up easily on how to use it. On Thu, Oct 30, 2014 at 2:02 PM, Rock Lee rocklee_...@sina.com wrote: Hi, everyone I am implementing a

Re: Some Kernel Questions/Confusions [Pls help]

On Mon, Oct 27, 2014 at 8:08 PM, Er Krishna erkris...@gmail.com wrote: Hi Valdis, Many thanks for the mail and quick answers. Regarding the point 4 I know there won't be any page fault otherwise its going to be a complete mess for the kernel. But since I have the confusion due to wrong

Re: How to safely access inode/dentry obtained from struct page *?

On 30-Aug-2014 10:49 AM, Joshi joshii...@gmail.com wrote: I am trying to obtain file name at block layer level (above IO scheduler). At this level I receive bio structure, within which page pointers are kept. Thereby I do following to obtain the inode and dentry - struct inode *inode_ptr =

Re: How to safely access inode/dentry obtained from struct page *?

On 01-Sep-2014 10:18 AM, Pranay Srivastava pran...@gmail.com wrote: On 30-Aug-2014 10:49 AM, Joshi joshii...@gmail.com wrote: I am trying to obtain file name at block layer level (above IO scheduler). At this level I receive bio structure, within which page pointers are kept. Thereby

Re: Query regarding page access protection flags linux kernel

On Tue, Aug 5, 2014 at 4:49 PM, ravali pullela rpravali...@gmail.com wrote: Hello, I am trying to understand the page fault handling and MMU. These are my queries 1) What is the exact difference between the protection flags in vm_area_struct and pte's protection flags of the page.

Re: How to implement a driver's read and write operations with synchronization properly

On 29-Jul-2014 1:34 PM, Anh Le anhlq2...@gmail.com wrote: Hi everyone, I'm trying to write a misc char driver with read and write operations, and I choose reader writer lock for synchronization between them. Suppose that when writing 2000 bytes, the write operation is called twice, each time

Re: How to implement a driver's read and write operations with synchronization properly

On 29-Jul-2014 5:54 PM, Anh Le anhlq2...@gmail.com wrote: Thanks, Jonathan, for the quick reply. On Tue, Jul 29, 2014 at 3:36 PM, Jonathan Neuschäfer j.neuschae...@gmx.net wrote: Which write operation is called twice in your scenario? It's the write method of the struct file_operations

Re: Building a software serial driver

. Here's a functional driver that takes a GPIO pin and creates a read-only serial TTY: So multiple open don't harm? The startup routine is called only once is that right? https://github.com/tdfischer/gpio_serial/blob/master/gpiotty.c :) On Tuesday, June 24, 2014 21:27:46 Pranay Srivastava

Re: about pr_debug

On Wed, Jun 25, 2014 at 11:39 AM, lx lxlenovos...@gmail.com wrote: hi all: I'm confused with pr_debug. My codes is: ### #include linux/module.h #include linux/kernel.h static int __init init_page_dir(void) { pr_debug(Hello world\n);

Re: About bio_endio

On Wed, Jun 25, 2014 at 10:31 AM, Alvin Abitria abitria.al...@gmail.com wrote: Hello Pranay, Thanks for your very helpful insights! I hope you don’t mind if I continue with more questions on block layer :-) Surely. On Jun 25, 2014 2:09 AM, Pranay Srivastava pran...@gmail.com wrote

Re: Building a software serial driver

Hi Torrie On Mon, Jun 23, 2014 at 11:45 PM, Torrie Fischer tdfisc...@hackerbots.net wrote: Greetings fellow newbies. I'm toying around with a Raspberry PI and trying to create a driver that takes a single GPIO pin and turns it into a read-only TTY device because using the userspace GPIO

Re: Building a software serial driver

Hi Torrie, On Tue, Jun 24, 2014 at 6:26 PM, Torrie Fischer tdfisc...@hackerbots.net wrote: Hi, Pranay. Thanks for having a look. On Tuesday, June 24, 2014 13:42:35 Pranay Srivastava wrote: I looked at uart_register code, it seems there's no read callback so that's why you are getting

Re: About bio_endio

Hello Alvin, On Tue, Jun 24, 2014 at 9:53 PM, Alvin Abitria abitria.al...@gmail.com wrote: Hello Pranay! Thanks for your reply. I apologize for my very late reply, I was very preoccupied earlier at work. On Tue, Jun 24, 2014 at 1:07 PM, Pranay Srivastava pran...@gmail.com wrote: Hello

Re: About bio_endio

Hello Alvin, On Mon, Jun 23, 2014 at 10:39 PM, Alvin Abitria abitria.al...@gmail.com wrote: Hello, I'm developing a block driver using the make_request method, effectively bypassing existing scsi or request stack in block layer. So that means im directly working with bios. As prescribed in

Re: Understanding #ifdef in .h files

Hi Harold On 6/20/14, Harold André harold.an...@gmx.fr wrote: Hi, I try to understand how #ifdef in .h files works. I read Greg Kroah-Hartman's Coding style paper http://www.kroah.com/linux/talks/ols_2002_kernel_codingstyle_talk/html/mgp00031.html And as he says, i try to do a simple

Re: Understanding #ifdef in .h files

On Fri, Jun 20, 2014 at 6:29 PM, Harold André harold.an...@gmx.fr wrote: Le Fri, 20 Jun 2014 16:36:58 +0530, Pranay Srivastava pran...@gmail.com a écrit : You say here you will define the function else where if TEST_FUNCTION is defined #ifdef TEST_FUNCTION void test(int *value

Re: Why the page tables are needed for lowmem?

On Thu, Jun 19, 2014 at 8:51 AM, sandeep kumar coolsandyfor...@gmail.com wrote: Hi All i was going through mm initialization code, and saw paging_init() implementation. it has a function map_lowmem(). I was wondering why do we need page table entries for lowmem ?? I hope you understand how

Re: Disabling a BH : spin_lock_bh or local_bh_disable.

On Fri, Jun 13, 2014 at 12:27 PM, priyaranjan priyaranjan45...@gmail.com wrote: Hi All, I was referring to Unreliable Guide To Locking by Paul Rusty Russell. Here is a quote below :- If a bottom half shares data with user context, you have two problems. Firstly, the current user context

Re: Beginner guide

On Wed, Jun 11, 2014 at 11:58 AM, Prudhvee Narasimha Sadha prudhvi.s...@gmail.com wrote: Hi, My name is Prudhvee and I'm purusing my undergraduate second year. I'm intrested in kernel development but I'm unable to understand how to get into it. Can you please help me to become a kernel

Re: Beginner guide

On Jun 11, 2014 7:19 PM, Ben b...@cock.li wrote: While on the subject of books, is Understanding the Linux Kernel - 3rd edition worth reading (it covers 2.6)? yes. if you've hardcopy then open the code and browse through it. otherwise use two monitors. :-p. switching back n forth through

Re: Calling hibernate from workqueue

On Jun 9, 2014 8:47 PM, AYAN KUMAR HALDER ayankum...@gmail.com wrote: Hi, I am using a arm based muticore platform. I intend to call hibernate from a push button interrupt. I have initialized a workqueue for calling hibernate() and have scheduled it in the push button interrupt service

Re: non-static init in a basic kernel module

On Jun 9, 2014 10:15 PM, Warren Turkal w...@penguintechs.org wrote: Hey, I was writing a basic hello world module. I am using Ubuntu, so I installed linux-headers package that corresponded to my kernel. It's strange because all of the examples that I saw (including from modules in the

Re: Invoking a system using syscall()

On Sat, Jun 7, 2014 at 11:20 AM, Dipanjan Das mail.dipanjan@gmail.com wrote: Hi, I want to invoke getpid() system call using syscall. Here's the code snippet below. But, I can't find anything in dmesg|tail output. What are you trying to see there? Why should any output come over there?

Re: remote devices

of your own that can communicate for the GPU exclusively. Perhaps you can give it a try and then see if NFS is better option. -Riya On Sat, May 31, 2014 at 11:35 PM, Pranay Srivastava pran...@gmail.com wrote: Hi Riya, It's actually not the major and minor numbers, sure they decide the driver

Fwd: Question regarding ISA DMA

Hi, I'm trying to understand how to use the ISA DMA controller with my PC. What I'm not able to understand is that why is it required to have an IRQ line associated with my device that is going to initiate the DMA? As I understand DMA controller would be signalling CPU[Correct?] so this IRQ

Re: remote devices

Hi Riya, It's actually not the major and minor numbers, sure they decide the driver and the device but when it comes to read/write you actually have file_operations. So I digged around a bit and this is the one you should look into, nfs_fhget If you see at the end where it installs the

Question regarding ISA DMA

Hi, I'm trying to understand how to use the ISA DMA with my PC. What I'm not able to understand is that why is it required to have an IRQ line associated with my device that is going to initiate the DMA? As I understand DMA controller would be signalling CPU[Correct?] so this IRQ would be

Re: How to diasble interrupt of current core in multicore cpu

are you looking for local_irq_disable? On Fri, May 30, 2014 at 1:42 PM, J.Hwan Kim kernel.frog@gmail.com wrote: Hi, everyone How to disable interrupt for current core in multicore CPU? Thanks in advance Kim. ___ Kernelnewbies mailing list

Capturing all writes as fault on a memory mapped page.

Hi I need to capture all writes on page which is memory mapped by the user program. I've tried setting the vm_page_prot by disabling the VM_WRITE flag but even then the page fault occurs only once during the first write. VM_SHARED is set to stop COW in the __do_fault. I was also trying to

Re: Capturing all writes as fault on a memory mapped page.

On 5/28/14, Greg KH g...@kroah.com wrote: On Wed, May 28, 2014 at 06:47:24PM +0530, Pranay Srivastava wrote: Hi I need to capture all writes on page which is memory mapped by the user program. For what and what are you going to do with them once you capture them? This is just

Re: Capturing all writes as fault on a memory mapped page.

On 5/28/14, Greg KH g...@kroah.com wrote: On Wed, May 28, 2014 at 07:13:55PM +0530, Pranay Srivastava wrote: Actually trying to do something like if there's a write being done on the page by a task currently then other tasks should wait( was hoping that the fault handler code would be called

Re: Open and copy a file from the kernel

On Tue, May 27, 2014 at 12:49 PM, Nada Saif nada.sa...@gmail.com wrote: Hi, I want to process a copy operation from file sent from user space - this copying should be inside the kernel.. I read about using filp_open , will this help me ? I guess you want to open the files inside kernel and

Re: Open and copy a file from the kernel

diffs which you can easily do in script. If you are not doing the above things I said, then my bad. You need to tell some more about project then maybe I can help. Regards On May 27, 2014 11:29 AM, Pranay Srivastava pran...@gmail.com wrote: On Tue, May 27, 2014 at 12:49 PM, Nada Saif nada.sa

Re: Regarding parsing of cifs header

On Mon, May 26, 2014 at 1:20 PM, Ramana Reddy gtvrre...@gmail.com wrote: Thanks for your reply. First thing is that I do not want to modify the existing cifs driver. I have my own virtual Ethernet driver, where the skb buffer is available to parse. Now, I want to extract the cifs header from

Re: Regarding parsing of cifs header

On Monday, May 26, 2014, Ramana Reddy gtvrre...@gmail.com wrote: Hi Pranay Srivastava, Thanks for your reply. I just want to copy the payload into the buffer with out cloning or copying of skb to reduce the delay as it has to do on every packet. Is there any method in the linux kernel to get

Re: Can a Bottom half be scheduled from a kernel thread

do memcpy, but no copy_to/copy_from On Tue, May 13, 2014 at 6:28 AM, Pranay Srivastava pran...@gmail.com wrote: On May 13, 2014 2:36 AM, Vishwas Srivastava vishu.ker...@gmail.com wrote: Hi All, This may sound a dumb question. I just want to know if a tasklet can

Re: Can a Bottom half be scheduled from a kernel thread

On May 13, 2014 2:36 AM, Vishwas Srivastava vishu.ker...@gmail.com wrote: Hi All, This may sound a dumb question. I just want to know if a tasklet can be scheduled from a kernel thread. You can do tasklet_schedule in case I am getting your question. what are the pros and crons of

Re: Question related to nfs(network file system) in linux kernel.

On May 13, 2014 1:03 AM, Sivakumar V sivakumar...@gmail.com wrote: Hi All, I want a requirement to intercept rpc call to nfs(network file system) or get hold of nfs buffer in kernel space and get data from the buffer to print it. You probably should look for xpo structures of TCP and UDP .

Re: LKM related API documentation

On Sunday, May 4, 2014, Abhijeet Kasurde abhijeetkasurd...@gmail.com wrote: Hi All, Can anyone point me to any location of documentation related to Linux Kernel Module APIs ? I am specifically looking for following APIs - 1. find_symbol 2. request_module 3. find_module etc. hi Abhijeet,

Re: Regarding skb and net_device.

consists also of the net_device to be used) is known before. Best Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Sat, May 3, 2014 at 11:33 AM, Pranay Srivastava pran...@gmail.com wrote: Hi, This is probably a stupid question, but i'm not able to find the answer. How does

Regarding skb and net_device.

Hi, This is probably a stupid question, but i'm not able to find the answer. How does the networking subsystem decides which device to use for sending the skb. Can some one please guide me to the particular code. I seem to get lost in there :( -- ---P.K.S

Regarding net_device_ops

Hi Referring to Documentation/networking/netdevices.txt a) ndo-ndo_start_xmit if written as is will be thread safe? [Correct?] NETIF_F_LLTX is not set only then this is true. But dev_queue_xmit(skb) doesn't seem to take any lock, neither does dev_hard_start_xmit. Please let me know if i'm

Regarding skb and skb_frags

I was going through a function dev_alloc_skb and it seems that the skb_frags are created only if the data length passed is PAGE_SIZE. My question is that an Ethernet frame won't be bigger than 1500 bytes [correct?] so there never will be skb_frags for Ethernet frames. However I've seen

Re: Regarding skb and skb_frags

On Thu, May 1, 2014 at 7:29 PM, valdis.kletni...@vt.edu wrote: On Thu, 01 May 2014 16:12:43 +0530, Pranay Srivastava said: My question is that an Ethernet frame won't be bigger than 1500 bytes [correct?] Incorrect. 10G and faster ethernet support jumbograms. We run our HPC 10G network

Re: Regarding skb and skb_frags

On Thu, May 1, 2014 at 9:50 PM, Jeff Haran jeff.ha...@citrix.com wrote: -Original Message- From: kernelnewbies-boun...@kernelnewbies.org [mailto:kernelnewbies-boun...@kernelnewbies.org] On Behalf Of Pranay Srivastava Sent: Thursday, May 01, 2014 7:10 AM To: valdis.kletni...@vt.edu

Re: Eudyptula Challenge Task 01

On Tue, Apr 29, 2014 at 8:40 PM, me storage me.storage...@gmail.com wrote: Hi i every one i am new to linux kernel programming .I am participating in Eudyptula Challenge .Recently i submitted my solutions to Task 01 but i gives me reply like the below Please read the requirements for the

Re: Question about VFS

On Wed, Apr 30, 2014 at 9:14 AM, Adam Fowler ajf2...@columbia.edu wrote: I've been trying to implement a file system using vfs and I've got mkdir and touch working but I can't seem to get echo blah new file to create a new Can you see if you are able to get the user space buffer and print it?

Re: Difference between seq_release and single_release ?

On Apr 24, 2014 10:12 PM, Abhijeet Kasurde abhijeetkasurd...@gmail.com wrote: Hi All, What is difference between seq_release and single_release API ? Can someone explain particular use case of these APIs ? From the code seq_file.c ,it seems seq_release compliments seq_open While

Re: How to submit for eudyptula-challenge

Hi Set your log level to 8 so you can see your messages. The pr_ *ones Should be good. Also check how to enable that macro for specific or all files of your module. On Mar 25, 2014 10:18 AM, wangyubin harry198...@gmail.com wrote: OK, I will try to use that. :-) Best Regards! wangyubin

Re: how to get PFN of page cache?

On 3/20/14, pravin jadav pravin.jada...@gmail.com wrote: just retrive want to page frame number of pagecache page that's fine but anything specific you are looking for? printing pfns only doesn't sound interesting. I hope there will be more to it. -- Pranay Srivastava

Re: A new way to dive into the kernel!

On Mar 19, 2014 10:43 AM, Srivardhan M S srivardha...@gmail.com wrote: Hi Anand, I actually copy pasted the code in the email itself. It worked for my 1st assignement and now am doing my second assignement. You aren't supposed to copy. Try to type by hand you'll learn more. Thank-you, Sri

Re: A new way to dive into the kernel!

in the file and compiled it. -Sri On Wed, Mar 19, 2014 at 11:34 AM, Pranay Srivastava pran...@gmail.com wrote: On Mar 19, 2014 10:43 AM, Srivardhan M S srivardha...@gmail.com wrote: Hi Anand, I actually copy pasted the code in the email itself. It worked for my 1st assignement and now am

Re: Is my custom field added in page struct guaranteed zero when a page is allocated ?

On Mar 14, 2014 9:26 PM, 朱 zly.k...@163.com wrote: hi, I add a u64 field in struct page to record corresponding disk sector postion. I will change and read this field when dealing with page cache staff. As you already have modified page struct, how about modifying prep_new_page as well. Put a

Re: A new way to dive into the kernel!

On Mar 14, 2014 9:50 PM, jimmy.li coder.l...@qq.com wrote: I have tried thunderbird, but it always send attachments with base64 encoding. It's there any solution to this issue? Tried kmail in case you use kde? I have kmail on suse and it works perfect. I'm using mutt, It's ok.

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