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Date: Mon, 11 Jun 2007 13:18:21 +0200
From: "Jesper Juhl" <jesper.juhl@...il.com>
To: Surya <surya.prabhakar@...ro.com>
Cc: emoenke@...g.de, "Linux Kernel" <linux-kernel@...r.kernel.org>,
kernel-janitors@...ts.osdl.org
Subject: Re: [PATCH]: complete cleanup of check_region
On 08/06/07, Surya <surya.prabhakar@...ro.com> wrote:
<snip>
> > > msg(DBG_INI,"check_drives done.\n");
> > > + if(request_region_flag==0)
> > > + release_region(addr[1],4);
> >
> > I know the driver in its current version just tests if the region is
> > available and doesn't hang on to it, but I'm wondering if that's not a
> > bug. Shouldn't we actually hold on to this region as long as the
> > driver is loaded and only release the region in the sbpcd_exit()
> > function, just loke we do with the "CDo_command" region?
> But if any of the conditions fail after the request_region code, it is
> returning an error and exiting out of init. Dont we need to cleanup
> request_region's allocation before we exit.
Probably.
> Infact I had a feeling that
> CDo_command region cleanup was not perfect. Did a cleanup of both the
> regions wherever we have a return out of the function.
>
That makes sense to me.
> Please have a look at the below patch.
>
>
> diff --git a/drivers/cdrom/sbpcd.c b/drivers/cdrom/sbpcd.c
> index a1283b1..0a85b1b 100644
> --- a/drivers/cdrom/sbpcd.c
> +++ b/drivers/cdrom/sbpcd.c
> @@ -358,6 +358,10 @@
> * Add bio/kdev_t changes for 2.5.x required to make it work again.
> * Still room for improvement in the request handling here if anyone
> * actually cares. Bring your own chainsaw. Paul G. 02/2002
> + *
> + *
Why two blank comment lines? Isn't one enough?
> + * Cleaned up the reference for deprecated check_region to
> + * request_region. - Surya Prabhakar N 08/07/2007
> */
>
>
> @@ -555,6 +559,8 @@ static struct cdrom_read_audio read_audio;
> static unsigned char msgnum;
> static char msgbuf[80];
>
> +static int addr[2];
> +
> static int max_drives = MAX_DRIVES;
> module_param(max_drives, int, 0);
> #ifndef MODULE
> @@ -5638,7 +5644,7 @@ int __init sbpcd_init(void)
> #endif
> {
> int i=0, j=0;
Blank line between variable declarations and code please.
> - int addr[2]={1, CDROM_PORT};
> + addr[2]={1, CDROM_PORT};
> int port_index;
Keep the variables together and seperate from the code. Like this :
{
int i=0, j=0;
int port_index;
addr[2]={1, CDROM_PORT};
...
>
> sti();
Just in case you are bored, at some point those cli()/sti() need to go
away as well and be replaced with proper locking. But that's a
different patch :-)
> @@ -5670,9 +5676,9 @@ int __init sbpcd_init(void)
> {
> addr[1]=sbpcd[port_index];
> if (addr[1]==0) break;
> - if (check_region(addr[1],4))
> + if (!request_region(addr[1],4, "sbpcd driver"))
> {
> - msg(DBG_INF,"check_region: %03X is not free.\n",addr[1]);
> + msg(DBG_INF,"request_region: %03X is not free.\n",addr[1]);
> continue;
> }
> if (sbpcd[port_index+1]==2) type=str_sp;
> @@ -5699,6 +5705,7 @@ int __init sbpcd_init(void)
> if (ndrives==0)
> {
> msg(DBG_INF, "No drive found.\n");
> + release_region(addr[1],4);
If we get here after actually having obtained a region an ndrives is
then 0, then we should ofcourse release the region before we bail out.
makes sense.
> #ifdef MODULE
> return -EIO;
> #else
> @@ -5775,6 +5782,7 @@ int __init sbpcd_init(void)
> if (!request_region(CDo_command,4,major_name))
> {
> printk(KERN_WARNING "sbpcd: Unable to request region 0x%x\n", CDo_command);
> + release_region(addr[1],4);
> return -EIO;
> }
>
This makes sense. If we bail out due to not being able to obtain the
CDo_command region, then we should release the other region.
> @@ -5788,6 +5796,8 @@ int __init sbpcd_init(void)
> #endif /* SOUND_BASE */
>
> if (register_blkdev(MAJOR_NR, major_name)) {
> + release_region(CDo_command,4);
> + release_region(addr[1],4);
> #ifdef MODULE
> return -EIO;
> #else
> @@ -5801,6 +5811,7 @@ int __init sbpcd_init(void)
> sbpcd_queue = blk_init_queue(do_sbpcd_request, &sbpcd_lock);
> if (!sbpcd_queue) {
> release_region(CDo_command,4);
> + release_region(addr[1],4);
> unregister_blkdev(MAJOR_NR, major_name);
> return -ENOMEM;
> }
> @@ -5834,6 +5845,7 @@ int __init sbpcd_init(void)
> printk("Can't unregister %s\n", major_name);
> }
> release_region(CDo_command,4);
> + release_region(addr[1],4);
> blk_cleanup_queue(sbpcd_queue);
> return -EIO;
> }
> @@ -5850,6 +5862,7 @@ int __init sbpcd_init(void)
> if (sbpcd_infop == NULL)
> {
> release_region(CDo_command,4);
> + release_region(addr[1],4);
> blk_cleanup_queue(sbpcd_queue);
> return -ENOMEM;
> }
> @@ -5894,6 +5907,7 @@ static void sbpcd_exit(void)
> return;
> }
> release_region(CDo_command,4);
> + release_region(addr[1],4);
> blk_cleanup_queue(sbpcd_queue);
> for (j=0;j<NR_SBPCD;j++)
> {
>
> Kindly update if this is Ok. I will proceed with the original patch.
>
This looks a lot better to me. I have only given it a quick look, but
I don't see any major problems.
> -surya.
>
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>
Please tell your mail client not to include crap like that when
sending to public mailing lists.
--
Jesper Juhl <jesper.juhl@...il.com>
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please http://www.expita.com/nomime.html
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