Date: Fri, 04 Mar 2005 08:41:33 +0100 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Andrew Gallatin <gallatin@cs.duke.edu> Cc: freebsd-current@freebsd.org Subject: Re: panic: dev ... is on clonelist Message-ID: <14919.1109922093@critter.freebsd.dk> In-Reply-To: Your message of "Thu, 03 Mar 2005 18:01:17 EST." <16935.38717.96802.616769@grasshopper.cs.duke.edu>
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A lot have changed from RELENG_5 to -current.
I'm a bit hung up this weekend, but if you mail your driver to me
I will take a look as soon as I can.
Poul-Henning
n message <16935.38717.96802.616769@grasshopper.cs.duke.edu>, Andrew Gallatin writes:
>
>Hi,
>
>I've got a character driver which I'd like to make behave as much like
>a linux cloning driver as possible because I'm maintaining linux
>binary compat. I'm using the cloning interface in 5.x and 6.0.
>
>My driver *seems* to work fine in 5.4, even with INVARIANTS. But in
>6.0, I'm dying with: "dev 0xc2f89c00 (mx_fake.1) is on clonelist".
>>From the si_drv{1,2} fields, it looks like the cdev was closed.
>Did something change between 5.x and 6.0? Or am I doing something
>that's bogus in 5.x and I'm just getting lucky?
>
>What I want is to have a unique cdev generated for each open
>of the device. Then I would like to use the si_drv1 and
>si_drv2 fields of the cdev to hang per-open information from.
>
>So, if the user opens /dev/mx0, then I'd like a unique cdev generated.
>And if somebody else opens /dev/mx0, then I'd like a second unique cdev
>generated.
>
>What I've been doing (and what seemed to work in 5.x) was this:
>
>- Don't make any /dev/mx devices at all, use clone handler for all
> device creation.
>
>- Use dev_stdclone() in to get the "real" unit number (0 from /dev/mx0,
> 1 from /dev/mx1, etc, where the unit corresponds to a physical
> device).
>
>- Prepare a "fake" device for the user, so that every open
> has a unique cdev. To do this, I have been calling
> clone_create() with a "fake" unit number (starting at 0,
> and increasing) until I find either a free "fake" cdev, or
> a "fake" cdev which does not exist. By free, I make
> a cdev whose si_drv1 indicates he's free. By "fake",
> I mean I don't care what the unit number is.
>
>- if the "fake" cdev does not exist, create a /dev/mx_fake.%d,
> using the "fake" unit number via make_dev()
>
>- using the cdev obtained from either clone_create(), or make_dev(),
> set (*cdev)->si_drv1 to the "real" unit number so my open
> routine knows what to do.
>
>
>Any idea what I'm doing wrong?
>
>Thanks for the help,
>
>Drew
>
>
>
>static void
>mx_clone(void *arg, char *name, int namelen, struct cdev **cdev)
>{
> int u, i, privileged, mode, fake_unit, free_cdev;
>
> if (*cdev != NULL) {
> /* printf("mx_clone called with non-null struct cdev *??\n");*/
> return;
> }
> if (dev_stdclone(name, NULL, "mxp", &u)) {
> privileged = 1;
> mode = 0600;
> } else if (dev_stdclone(name, NULL, "mx", &u)) {
> privileged = 0;
> mode = 0666;
> } else {/* Don't recognize the name */
> return;
> }
> if (u >= mx_num_instances)
> return; /* unit too large */
>
> if (privileged && suser(curthread))
> return; /* EPERM */
>
>
> /* Now we iterate over our clone list. We start at index 0, and
> keep going until we find a free clone. We know the clone is free
> because either the cdev is null (in which case it was never
> allocated, and no /dev/mx_fake.%d entry exists) or the cdev is
> non-null, and its si_drv1 field is null (which means that it has
> been closed by another process, and a /dev/mx_fake.%d exists).
>
> Its important to find priviliged devices, so we always search
> only odd units when we want a priviliged device.
> */
>
> fake_unit = 0 + privileged;
>
> do {
> i = clone_create(&mx_clones, &mx_cdevsw, &fake_unit, cdev, 0);
> free_cdev = i || ((*cdev)->si_drv1 == NULL);
>#if 1
> printf("dev: %d. i: %d", fake_unit, i);
> if (i == 0)
> printf(" drv1: %p", (*cdev)->si_drv1);
> else
> printf(" drv1: NULL");
> printf(" Free = %d\n", free_cdev);
>#endif
> if (!free_cdev)
> fake_unit+=2;
> } while (!free_cdev);
>
> if (i) {
> /* need to allocate a new /dev/mx_fake.%d device node */
> *cdev = make_dev(&mx_cdevsw, unit2minor(fake_unit),
> UID_ROOT, GID_WHEEL,
> mode, "mx_fake.%d", fake_unit);
> }
> if (*cdev != NULL) {
> /* Treat si_drv1 like a bitfield. Low bit is "in use" flag,
> second bit is privileged bit, remainder is the real unit that
> the opener requested */
> mx_always_assert((*cdev)->si_drv1 == NULL);
> (*cdev)->si_drv1 = (void *)(uintptr_t)(1 | (privileged << 1) | (u << 2));
> (*cdev)->si_drv2 = NULL;
> }
>}
>
>
>
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--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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