From: James Bottomley <jbottomley@parallels.com>
To: "hch@lst.de" <hch@lst.de>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"hare@suse.de" <hare@suse.de>
Subject: Re: [PATCH 3/9] scsi: use external buffer for command logging
Date: Wed, 14 Jan 2015 15:24:09 +0000 [thread overview]
Message-ID: <1421249081.2083.6.camel@parallels.com> (raw)
In-Reply-To: <20150114093619.GA11129@lst.de>
On Wed, 2015-01-14 at 10:36 +0100, hch@lst.de wrote:
> On Tue, Jan 13, 2015 at 06:56:17PM +0000, James Bottomley wrote:
> > I really hate using an on-stack buffer here ... we're pretty deep in the
> > call chain already.
> >
> > Since it's just required for printing a "command: " prefix, why not just
> > use scsi_print_command()?
>
> Both the ch and sr callers are not really a problem in terms of stack
> usage, as they are directly in file operations of character or block
> devices, so the whole FS/MM stack stack problem isn't an issue.
Trying to calculate minutely how much additional overhead there is isn't
really the point. The point is we can just use a different function
that doesn't consume the on stack buffer, so we should, just as a matter
of best practise. I agree it would have been a more finely balanced
problem if we definitely needed the allocation
> But using higher level functions might still be useful here.
James
next prev parent reply other threads:[~2015-01-14 15:24 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-08 6:43 [PATCHv4 0/9] scsi logging update: the real thing Hannes Reinecke
2015-01-08 6:43 ` [PATCH 1/9] scsi: Implement per-cpu logging buffer Hannes Reinecke
2015-01-13 18:41 ` James Bottomley
2015-01-08 6:43 ` [PATCH 2/9] scsi: log request tag for scmd_printk() Hannes Reinecke
2015-01-08 6:43 ` [PATCH 3/9] scsi: use external buffer for command logging Hannes Reinecke
2015-01-13 18:56 ` James Bottomley
2015-01-14 9:36 ` hch
2015-01-14 15:24 ` James Bottomley [this message]
2015-01-08 6:43 ` [PATCH 4/9] libata: use __scsi_format_command() Hannes Reinecke
2015-01-08 6:43 ` [PATCH 5/9] scsi: use per-cpu buffer for formatting sense Hannes Reinecke
2015-01-08 6:43 ` [PATCH 6/9] scsi: use per-cpu buffer for formatting scsi_print_result() Hannes Reinecke
2015-01-08 6:43 ` [PATCH 7/9] scsi: Conditionally compile in constants.c Hannes Reinecke
2015-01-08 6:43 ` [PATCH 8/9] scsi: Do not display buffer pointers in scsi_log_send() Hannes Reinecke
2015-01-08 6:43 ` [PATCH 9/9] scsi_error: do not display kernel pointer in message logs Hannes Reinecke
2015-01-10 19:17 ` Elliott, Robert (Server Storage)
2015-01-11 18:39 ` Douglas Gilbert
2015-01-12 13:12 ` Ewan Milne
2015-01-12 13:29 ` Hannes Reinecke
2015-01-12 14:57 ` Ewan Milne
2015-01-12 15:18 ` Ewan Milne
2015-01-10 18:01 ` [PATCHv4 0/9] scsi logging update: the real thing Christoph Hellwig
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