From: Hannes Reinecke <hare@suse.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: James Bottomley <jbottomley@parallels.com>,
Christoph Hellwig <hch@infradead.org>,
linux-scsi@vger.kernel.org, Robert Elliott <elliott@hp.com>
Subject: Re: [PATCH 26/38] seq_buf: Move the seq_buf code to lib/
Date: Mon, 29 Sep 2014 16:08:08 +0200 [thread overview]
Message-ID: <542967C8.7060709@suse.de> (raw)
In-Reply-To: <20140929100438.36abd4ef@gandalf.local.home>
On 09/29/2014 04:04 PM, Steven Rostedt wrote:
> On Mon, 29 Sep 2014 13:58:55 +0200
> Hannes Reinecke <hare@suse.de> wrote:
>
>> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>>
>> The seq_buf functions are rather useful outside of tracing. Instead
>> of having it be dependent on CONFIG_TRACING, move the code into lib/
>> and allow other users to have access to it even when tracing is not
>> configured.
>>
>> The seq_buf utility is similar to the seq_file utility, but instead of
>> writing sending data back up to userland, it writes it into a buffer
>> defined at seq_buf_init(). This allows us to send a descriptor around
>> that writes printf() formatted strings into it that can be retrieved
>> later.
>>
>> It is currently used by the tracing facility for such things like trace
>> events to convert its binary saved data in the ring buffer into an
>> ASCII human readable context to be displayed in /sys/kernel/debug/trace.
>>
>> It can also be used for doing NMI prints safely from NMI context into
>> the seq_buf and retrieved later and dumped to printk() safely. Doing
>> printk() from an NMI context is dangerous because an NMI can preempt
>> a current printk() and deadlock on it.
>>
>> Link: http://lkml.kernel.org/p/20140619213952.058255809@goodmis.org
>
> I don't know where this is going, but I'm currently rewriting this
> code. Please don't add it yet to the kernel yet. I'm working on getting
> seq_buf and seq_file to be more inlined with each other. A much better
> sell if we can remove code with this change.
>
Hmm. I guess I'll be removing the respective patches then.
I can get quite the same results with using scnprintf(); the seq_buf
abstraction was just a nice way of coding.
No substantial difference here.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
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next prev parent reply other threads:[~2014-09-29 14:08 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-29 11:58 [PATCHv3 00/38] scsi logging update Hannes Reinecke
2014-09-29 11:58 ` [PATCH 01/38] Remove scsi_cmd_print_sense_hdr() Hannes Reinecke
2014-09-29 11:58 ` [PATCH 02/38] sd: Remove scsi_print_sense() in sd_done() Hannes Reinecke
2014-09-29 11:58 ` [PATCH 03/38] aha152x: Debug output update and whitespace cleanup Hannes Reinecke
2014-09-29 11:58 ` [PATCH 04/38] scsi: introduce sdev_prefix_printk() Hannes Reinecke
2014-09-29 11:58 ` [PATCH 05/38] scsi: Use sdev as argument for sense code printing Hannes Reinecke
2014-09-29 11:58 ` [PATCH 06/38] acornscsi: use scsi_print_command() Hannes Reinecke
2014-09-29 11:58 ` [PATCH 07/38] fas216: Update logging messages Hannes Reinecke
2014-09-29 11:58 ` [PATCH 08/38] 53c700: remove scsi_print_sense() usage Hannes Reinecke
2014-09-29 11:58 ` [PATCH 09/38] scsi: stop decoding if scsi_normalize_sense() fails Hannes Reinecke
2014-09-29 11:58 ` [PATCH 10/38] scsi: do not decode sense extras Hannes Reinecke
2014-09-29 11:58 ` [PATCH 11/38] scsi: use 'bool' as return value for scsi_normalize_sense() Hannes Reinecke
2014-09-29 11:58 ` [PATCH 12/38] scsi: remove scsi_print_status() Hannes Reinecke
2014-09-29 11:58 ` [PATCH 13/38] Implement scsi_opcode_sa_name Hannes Reinecke
2014-09-29 19:29 ` Douglas Gilbert
2014-09-30 5:50 ` Hannes Reinecke
2014-09-29 11:58 ` [PATCH 14/38] scsi: merge print_opcode_name() Hannes Reinecke
2014-09-29 11:58 ` [PATCH 15/38] scsi: consolidate opcode lookup in scsi_opcode_sa_name() Hannes Reinecke
2014-09-29 11:58 ` [PATCH 16/38] scsi: remove last argument from print_opcode_name() Hannes Reinecke
2014-09-29 11:58 ` [PATCH 17/38] scsi: Remove scsi_print_command when calling abort Hannes Reinecke
2014-09-29 11:58 ` [PATCH 18/38] scsi: separate out scsi_(host|driver)byte_string() Hannes Reinecke
2014-09-29 11:58 ` [PATCH 19/38] sd: Cleanup logging Hannes Reinecke
2014-09-29 11:58 ` [PATCH 20/38] scsi: simplify scsi_log_(send|completion) Hannes Reinecke
2014-09-29 11:58 ` [PATCH 21/38] scsi: fixup logging messages in scsi_error.c Hannes Reinecke
2014-09-29 11:58 ` [PATCH 22/38] scsi: use shost argument in scsi_eh_prt_fail_stats Hannes Reinecke
2014-09-29 11:58 ` [PATCH 23/38] scsi_trace: add tracepoint for completion Hannes Reinecke
2014-09-29 11:58 ` [PATCH 24/38] tracing: Add trace_seq_buffer_ptr() helper function Hannes Reinecke
2014-09-29 11:58 ` [PATCH 25/38] tracing: Create seq_buf layer in trace_seq Hannes Reinecke
2014-09-29 11:58 ` [PATCH 26/38] seq_buf: Move the seq_buf code to lib/ Hannes Reinecke
2014-09-29 14:04 ` Steven Rostedt
2014-09-29 14:08 ` Hannes Reinecke [this message]
2014-09-29 11:58 ` [PATCH 27/38] Rearrange buffer formatting in printk() Hannes Reinecke
2014-09-30 16:16 ` Petr Mladek
2014-09-30 19:37 ` Petr Mladek
2014-09-29 11:58 ` [PATCH 28/38] Externalize string buffer for printk Hannes Reinecke
2014-09-30 16:39 ` Petr Mladek
2014-09-30 18:52 ` Hannes Reinecke
2014-09-29 11:58 ` [PATCH 29/38] Introduce dev_printk_string() and dev_printk_header() Hannes Reinecke
2014-09-29 16:58 ` Greg Kroah-Hartman
2014-09-30 5:48 ` Hannes Reinecke
2014-09-29 11:58 ` [PATCH 30/38] scsi: Use real functions for logging Hannes Reinecke
2014-09-29 11:59 ` [PATCH 31/38] scsi: log request tag for scmd_printk() Hannes Reinecke
2014-09-29 11:59 ` [PATCH 32/38] scsi: use external buffer for command logging Hannes Reinecke
2014-09-29 11:59 ` [PATCH 33/38] libata: use __scsi_print_command() Hannes Reinecke
2014-09-29 14:06 ` Tejun Heo
2014-09-29 14:10 ` Hannes Reinecke
2014-09-29 14:11 ` Tejun Heo
2014-09-29 11:59 ` [PATCH 34/38] scsi: Remove command pointer argument from logging messages Hannes Reinecke
2014-09-29 11:59 ` [PATCH 35/38] scsi: use seq_buf for formatting sense buffer Hannes Reinecke
2014-09-29 11:59 ` [PATCH 36/38] scsi: use seq_buf for formatting scsi_print_result() Hannes Reinecke
2014-09-29 11:59 ` [PATCH 37/38] scsi: Conditionally compile in constants.c Hannes Reinecke
2014-09-29 11:59 ` [PATCH 38/38] scsi_error: document scsi_try_to_abort_cmd Hannes Reinecke
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