linux-kernel - Re: [PATCH] SCSI: Remove redundant GFP

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Message-Id: <20070504011535.ff7181fb.akpm@linux-foundation.org>
Date:	Fri, 4 May 2007 01:15:35 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	"Robert P. J. Day" <rpjday@...dspring.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-scsi@...r.kernel.org,
	James Bottomley <James.Bottomley@...eleye.com>
Subject: Re: [PATCH] SCSI: Remove redundant GFP_KERNEL type flag in
 kmalloc().


Please be careful to add the appropriate cc's.

On Mon, 30 Apr 2007 04:37:22 -0400 (EDT) "Robert P. J. Day" <rpjday@...dspring.com> wrote:

> 
> Remove the apparently redundant GFP_KERNEL type flag in the call to
> kmalloc().
> 
> Signed-off-by: Robert P. J. Day <rpjday@...dspring.com>
> 
> ---
> 
> diff --git a/drivers/scsi/aic7xxx_old.c b/drivers/scsi/aic7xxx_old.c
> index a988d5a..765ded0 100644
> --- a/drivers/scsi/aic7xxx_old.c
> +++ b/drivers/scsi/aic7xxx_old.c
> @@ -6581,7 +6581,7 @@ aic7xxx_slave_alloc(struct scsi_device *SDptr)
>    struct aic7xxx_host *p = (struct aic7xxx_host *)SDptr->host->hostdata;
>    struct aic_dev_data *aic_dev;
> 
> -  aic_dev = kmalloc(sizeof(struct aic_dev_data), GFP_ATOMIC | GFP_KERNEL);
> +  aic_dev = kmalloc(sizeof(struct aic_dev_data), GFP_ATOMIC);

No, this converts the allocation from a robust one which can sleep into a
flakey one which cannot.

If we want to just clean this code up, we should switch to

	GFP_KERNEL|__GFP_HIGH

and add a comment explaining why we're turning on __GFP_HIGH (pointlessly,
I suspect).

However I suspect what the code really meant to do was to use just
GFP_KERNEL.  It's been that way since

commit 5c9342ceb292ac5c619db6eef4ef427a64bcd436
Author: torvalds <torvalds>
Date:   Thu Nov 7 04:54:32 2002 +0000

    Merge bk://linux-scsi.bkbits.net/scsi-dledford
    into home.transmeta.com:/home/torvalds/v2.5/linux
    
    2002/11/06 16:40:20-05:00 dledford
    aic7xxx_old: multiple updates and fixes, driver ported to scsi
        mid-layer new error handling scheme
-
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