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Message-Id: <200902101016.21297.bjorn.helgaas@hp.com>
Date: Tue, 10 Feb 2009 10:16:20 -0700
From: Bjorn Helgaas <bjorn.helgaas@...com>
To: Philippe De Muyter <phdm@...qel.be>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org, hancockrwd@...il.com, abelay@....edu,
lenb@...nel.org, stable@...nel.org
Subject: Re: [PATCH] floppy: release only the ports we actually requested
On Monday 09 February 2009 02:15:27 am Philippe De Muyter wrote:
> Bjorn,
>
> On Fri, Feb 06, 2009 at 10:57:06AM -0700, Bjorn Helgaas wrote:
> > On Friday 06 February 2009 09:20:13 am Bjorn Helgaas wrote:
> > > On Friday 06 February 2009 01:55:01 am Philippe De Muyter wrote:
> > > > Bjorn, Andrew,
> > > >
> > > > --
> > > >
> > > > With the last floppy patch, the floppy driver requests only the ports that
> > > > it really uses, but the code contains yet places where it releases those
> > > > unrequested ports. I don't know if it is harmfull, but I think it is cleaner
> > > > that the parameters of the release_region calls match the request_region ones.
> > >
> > > Doh! Boy, do I feel stupid. I doubt this is in any git trees yet,
> > > so I'll combine the two patches and send a cleaner one.
> >
> > Philippe, can you give this a once-over? I can compile it, but I don't
> > have a machine with a floppy drive handy to test it. Since you pointed
> > out all the places I forgot to change, I went ahead and factored out
> > the request/release stuff so they're all in one place now.
>
> As expected, your code works (tested linked in kernel and as a module),
> but I took your idea a little bit further, avoiding to keep 3 places with
> the io regions list, avoiding gotos and producing a slightly smaller binary.
> Of course, it is also compiled and tested both linked in kernel and in module
> mode.
>
> Is it OK for you ?
Looks great to me. Feel free to add a suitable changelog and my
Reviewed-by. Thanks for all your work on this!
Bjorn
> diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
> --- a/drivers/block/floppy.c
> +++ b/drivers/block/floppy.c
> @@ -558,6 +558,8 @@ static void recalibrate_floppy(void);
> static void recalibrate_floppy(void);
> static void floppy_shutdown(unsigned long);
>
> +static int floppy_request_regions(int);
> +static void floppy_release_regions(int);
> static int floppy_grab_irq_and_dma(void);
> static void floppy_release_irq_and_dma(void);
>
> @@ -4274,8 +4276,7 @@ static int __init floppy_init(void)
> FDCS->rawcmd = 2;
> if (user_reset_fdc(-1, FD_RESET_ALWAYS, 0)) {
> /* free ioports reserved by floppy_grab_irq_and_dma() */
> - release_region(FDCS->address + 2, 4);
> - release_region(FDCS->address + 7, 1);
> + floppy_release_regions(fdc);
> FDCS->address = -1;
> FDCS->version = FDC_NONE;
> continue;
> @@ -4284,8 +4285,7 @@ static int __init floppy_init(void)
> FDCS->version = get_fdc_version();
> if (FDCS->version == FDC_NONE) {
> /* free ioports reserved by floppy_grab_irq_and_dma() */
> - release_region(FDCS->address + 2, 4);
> - release_region(FDCS->address + 7, 1);
> + floppy_release_regions(fdc);
> FDCS->address = -1;
> continue;
> }
> @@ -4358,6 +4358,47 @@ out_put_disk:
>
> static DEFINE_SPINLOCK(floppy_usage_lock);
>
> +static struct io_region {
> + int offset;
> + int size;
> +} io_regions[] = {
> + { 2, 1 },
> + /* address + 3 is sometimes reserved by pnp bios for motherboard */
> + { 4, 2 },
> + /* address + 6 is reserved, and may be taken by IDE.
> + * Unfortunately, Adaptec doesn't know this :-(, */
> + { 7, 1 },
> +};
> +
> +static void floppy_release_allocated_regions(int fdc, struct io_region *p)
> +{
> + while (p != io_regions) {
> + p--;
> + release_region(FDCS->address + p->offset, p->size);
> + }
> +}
> +
> +#define ARRAY_END(X) (&((X)[ARRAY_SIZE(X)]))
> +
> +static int floppy_request_regions(int fdc)
> +{
> + struct io_region *p;
> +
> + for (p = io_regions; p < ARRAY_END(io_regions); p++) {
> + if (!request_region(FDCS->address + p->offset, p->size, "floppy")) {
> + DPRINT("Floppy io-port 0x%04lx in use\n", FDCS->address + p->offset);
> + floppy_release_allocated_regions(fdc, p);
> + return -EBUSY;
> + }
> + }
> + return 0;
> +}
> +
> +static void floppy_release_regions(int fdc)
> +{
> + floppy_release_allocated_regions(fdc, ARRAY_END(io_regions));
> +}
> +
> static int floppy_grab_irq_and_dma(void)
> {
> unsigned long flags;
> @@ -4399,18 +4440,8 @@ static int floppy_grab_irq_and_dma(void)
>
> for (fdc = 0; fdc < N_FDC; fdc++) {
> if (FDCS->address != -1) {
> - if (!request_region(FDCS->address + 2, 4, "floppy")) {
> - DPRINT("Floppy io-port 0x%04lx in use\n",
> - FDCS->address + 2);
> - goto cleanup1;
> - }
> - if (!request_region(FDCS->address + 7, 1, "floppy DIR")) {
> - DPRINT("Floppy io-port 0x%04lx in use\n",
> - FDCS->address + 7);
> - goto cleanup2;
> - }
> - /* address + 6 is reserved, and may be taken by IDE.
> - * Unfortunately, Adaptec doesn't know this :-(, */
> + if (floppy_request_regions(fdc))
> + goto cleanup;
> }
> }
> for (fdc = 0; fdc < N_FDC; fdc++) {
> @@ -4432,15 +4463,11 @@ static int floppy_grab_irq_and_dma(void)
> fdc = 0;
> irqdma_allocated = 1;
> return 0;
> -cleanup2:
> - release_region(FDCS->address + 2, 4);
> -cleanup1:
> +cleanup:
> fd_free_irq();
> fd_free_dma();
> - while (--fdc >= 0) {
> - release_region(FDCS->address + 2, 4);
> - release_region(FDCS->address + 7, 1);
> - }
> + while (--fdc >= 0)
> + floppy_release_regions(fdc);
> spin_lock_irqsave(&floppy_usage_lock, flags);
> usage_count--;
> spin_unlock_irqrestore(&floppy_usage_lock, flags);
> @@ -4502,8 +4529,7 @@ static void floppy_release_irq_and_dma(v
> old_fdc = fdc;
> for (fdc = 0; fdc < N_FDC; fdc++)
> if (FDCS->address != -1) {
> - release_region(FDCS->address + 2, 4);
> - release_region(FDCS->address + 7, 1);
> + floppy_release_regions(fdc);
> }
> fdc = old_fdc;
> }
>
--
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