September 2014 - kernelnewbies@kernelnewbies.org

How to get the inode - no path_lookup
by Rishi Agrawal Sept. 17, 2015

Sept. 17, 2015

Hi All, I had a module which used the path_lookup function to print the details of any file's inode. I now want to rewrite that module in order to show some juniors how to write some code in kernel. I am using 3.4.6 kernel, I tried finding out path_lookup but google showed that it has been removed. I tried the following code then which did not work . . . dentry = kern_path_create(AT_FDCWD, filename, &path, 1); if (IS_ERR(dentry)) { printk("Failed to obtain the dentry"); return; } its not returning dentry I again tried after seeing the implementation of vfs_stat function user_path_at(AT_FDCWD, filename, lookup_flags, &path); but this also fails. I am using a proc interface to pass the filename, and copying the filename into a kernel buffer. How can I get a copy of vfs inode for a file name. -- Regards, Rishi Agrawal

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Problem facing while running checkpatch.pl on linux-next tree
by Rahul Garg Dec. 25, 2014

Dec. 25, 2014

Hi All, I am trying to run checkpatch.pl on linux-next tree's staging folder. But whatever sub directory, I try to run it on. It is giving me the same error for all the files : ERROR: Does not appear to be a unified-diff format patch I thought that it might be a problem with my git. So I clone the git tree again. So can anyone help me, what am I missing ? Regards Rahul

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How to submit for eudyptula-challenge
by wangyubin Dec. 19, 2014

Dec. 19, 2014

Hello, I have dive into the eudyptula-challenge, but when I submit my result for task 01. I received a reply below: > Please print to the kernel debug log level. I have sended module(c file), Makefile, and dmesg output for load/unload the module. Could anyone to tell me what does this message mean? Thanks a lot! -- Best Regards! wangyubin

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Re: [PATCH] reformat_with_checkpatch: Add automation to checkpatch
by Greg KH Oct. 30, 2014

Oct. 30, 2014

On Fri, Jul 11, 2014 at 06:46:52PM -0700, Joe Perches wrote: > On Fri, 2014-07-11 at 18:39 -0700, Greg KH wrote: > > On Fri, Jul 11, 2014 at 06:21:27PM -0700, Joe Perches wrote: > > > A simple script to run checkpatch --fix for various types of > > > of cleanups. > ] > > drivers/staging/lustre/include/linux/lnet/api.h has no obvious style problems and is ready for submission. > > file: <drivers/staging/lustre/include/linux/lnet/api.h> description: <update c90 comment style> types:<c99_comments> > > Useless use of greediness modifier '+' in regex; marked by <-- HERE in m/(^\+.*) {8,8}+ <-- HERE \t/ at ./scripts/checkpatch.pl line 2217. > [] > > drivers/staging/lustre/include/linux/lnet/api.h has no obvious style problems and is ready for submission. > [] > > Is that expected? > > No, I haven't seen that. > > Can you tell me what git tree you're working on? My staging-next branch of staging.git on git.kernel.org > Also, can you use the scripts/checkpatch from -next > tag next-20140711 that will take a bit to checkout, I'll do that afterward. > My system has: > > $ perl --version > > This is perl 5, version 18, subversion 2 (v5.18.2) built for i686-linux-gnu-thread-multi-64int > (with 41 registered patches, see perl -V for more detail) I think this started showing up for me for perl 5.20. Let me go checkout linux-next and see if that fixes anything or not... thanks, greg k-h

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USB Start Learning Codebase
by nick Oct. 17, 2014

Oct. 17, 2014

Hey Guys, I am asking here about how to start with the usb stack as I am interested in learning that alongside the btrfs codebase. Nick

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How to debug this condition of "eth2: tx hang 1 detected on queue 11, resetting adapter" ?
by lx Oct. 14, 2014

Oct. 14, 2014

hi all: I want to send sk_buff by "dev_queue_xmit", when I just send 2 packets, the network card may be hang. I want to know how to debug this condition. the /var/log/messages is: ######################################### [root@10g-host2 test]# tail -f /var/log/messages Sep 29 10:38:22 10g-host2 acpid: waiting for events: event logging is off Sep 29 10:38:23 10g-host2 acpid: client connected from 2018[68:68] Sep 29 10:38:23 10g-host2 acpid: 1 client rule loaded Sep 29 10:38:24 10g-host2 automount[2210]: lookup_read_master: lookup(nisplus): couldn't locate nis+ table auto.master Sep 29 10:38:24 10g-host2 mcelog: failed to prefill DIMM database from DMI data Sep 29 10:38:24 10g-host2 xinetd[2246]: xinetd Version 2.3.14 started with libwrap loadavg labeled-networking options compiled in. Sep 29 10:38:24 10g-host2 xinetd[2246]: Started working: 0 available services Sep 29 10:38:25 10g-host2 abrtd: Init complete, entering main loop Sep 29 10:39:41 10g-host2 kernel: vmalloc mmap_buf=ffffc90016e29000 mmap_size=4096 Sep 29 10:39:41 10g-host2 kernel: insmod module wsmmap successfully! Sep 29 10:39:49 10g-host2 kernel: mmap_buf + 1024 is ffffc90016e29400 Sep 29 10:39:49 10g-host2 kernel: data ffffc90016e2942a, len is 42 Sep 29 10:39:49 10g-host2 kernel: udp data ffffc90016e29422 Sep 29 10:39:49 10g-host2 kernel: ip data ffffc90016e2940e Sep 29 10:39:49 10g-host2 kernel: eth data ffffc90016e29400 Sep 29 10:39:49 10g-host2 kernel: h_source is ffffc90016e29406, dev_addr is ffff880c235c4750, len is 6result is 0 Sep 29 10:39:50 10g-host2 kernel: mmap_buf + 1024 is ffffc90016e29400 Sep 29 10:39:50 10g-host2 kernel: data ffffc90016e2942a, len is 42 Sep 29 10:39:50 10g-host2 kernel: udp data ffffc90016e29422 Sep 29 10:39:50 10g-host2 kernel: ip data ffffc90016e2940e Sep 29 10:39:50 10g-host2 kernel: eth data ffffc90016e29400 Sep 29 10:39:50 10g-host2 kernel: h_source is ffffc90016e29406, dev_addr is ffff880c235c4750, len is 6result is 0 Sep 29 10:39:52 10g-host2 kernel: ixgbe 0000:03:00.0: eth2: Detected Tx Unit Hang Sep 29 10:39:52 10g-host2 kernel: Tx Queue <11> Sep 29 10:39:52 10g-host2 kernel: TDH, TDT <0>, <5> Sep 29 10:39:52 10g-host2 kernel: next_to_use <5> Sep 29 10:39:52 10g-host2 kernel: next_to_clean <0> Sep 29 10:39:52 10g-host2 kernel: ixgbe 0000:03:00.0: eth2: tx_buffer_info[next_to_clean] Sep 29 10:39:52 10g-host2 kernel: time_stamp <fffd3dd8> Sep 29 10:39:52 10g-host2 kernel: jiffies <fffd497f> Sep 29 10:39:52 10g-host2 kernel: ixgbe 0000:03:00.0: eth2: tx hang 1 detected on queue 11, resetting adapter Sep 29 10:39:52 10g-host2 kernel: ixgbe 0000:03:00.0: eth2: Reset adapter Sep 29 10:39:52 10g-host2 kernel: ixgbe 0000:03:00.0: master disable timed out Sep 29 10:39:53 10g-host2 kernel: ixgbe 0000:03:00.0: eth2: detected SFP+: 5 Sep 29 10:39:54 10g-host2 kernel: ixgbe 0000:03:00.0: eth2: NIC Link is Up 10 Gbps, Flow Control: RX/TX ######################################### some information of my computer is: ######################################### ethtool -i eth2 driver: ixgbe version: 3.21.2 firmware-version: 0x1bab0001 bus-info: 0000:03:00.0 supports-statistics: yes supports-test: yes supports-eeprom-access: yes supports-register-dump: yes supports-priv-flags: no LSB Version: :base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch Distributor ID: CentOS Description: CentOS release 6.5 (Final) Release: 6.5 Codename: Final ######################################### kernel version is: 2.6.32-431.el6.x86_64 Thank you for your help.

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eudyptula-challenge
by Sudip Mukherjee Oct. 5, 2014

Oct. 5, 2014

hi, has anyone heard from little about their task in last 2 weeks ? i am waiting since last 2 weeks and just wondering if things have again slowed down. thanks sudip

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Need to enable 2 MPP in dtsi file...
by siva sangeetha Oct. 1, 2014

Oct. 1, 2014

Hi, I am facing one issue, actually my requirement is i should enable 2 MPP, MPP4 & MPP6 in one node. how to achieve this?

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Alsa Driver - sound from gpio
by Raphael Philipe Oct. 1, 2014

Oct. 1, 2014

Hi! I'm a newbie on ALSA architecture. I would like to known if it would be possible to create a sound driver for a a PCM sound beeing acquired by the GPIO of a processor, like the ARM of a Beaglebone Black. Beaglebone has more than 32 bits of gpio so I intend to acquire the audio signal through a A/D CI (sigma delta) connected to a FPGA that would provide it to the Beaglebone Black in parallel form (PCM code), through the GPIO. Is that possible? Regards

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Test RAM read/write speed
by Ssagarr Patil Sept. 30, 2014

Sept. 30, 2014

Hi Folks, Is there any benchmarking tool to test read/write speed on Linux and which works on ARM ? Regards, --Sagar

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