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Code Issues Releases Activity

xen: fix xenstore dev

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Xenstore user-space device has two problems currently:
 - It does not correctly handle concurrent clients, because it's storing
   each client data in dev->si_drv1.
 - It does not correctly free this data when the client closes the device.

In order to solve both of this issues store the per-client data using
cdevpriv, which also comes with a hook in order to perform the necessary
cleanup on device close.

While there also make the device eternal.

Sponsored by: Citrix Systems R&D
Reported and Tested by: thompsa
MFC after: 2 weeks
This commit is contained in:
Roger Pau Monné 2015-02-16 09:53:43 +00:00
parent 39a58828ef
commit f79cdf2998
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=278844
1 changed files with 30 additions and 24 deletions
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54
sys/dev/xen/xenstore/xenstore_dev.c
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@ -77,7 +77,11 @@ static int
xs_dev_read(struct cdev *dev, struct uio *uio, int ioflag)
{
int error;
struct xs_dev_data *u = dev->si_drv1;
struct xs_dev_data *u;
error = devfs_get_cdevpriv((void **)&u);
if (error != 0)
return (error);
while (u->read_prod == u->read_cons) {
error = tsleep(u, PCATCH, "xsdread", hz/10);
@ -115,11 +119,15 @@ static int
xs_dev_write(struct cdev *dev, struct uio *uio, int ioflag)
{
int error;
struct xs_dev_data *u = dev->si_drv1;
struct xs_dev_data *u;
struct xs_dev_transaction *trans;
void *reply;
int len = uio->uio_resid;
error = devfs_get_cdevpriv((void **)&u);
if (error != 0)
return (error);
if ((len + u->len) > sizeof(u->u.buffer))
return (EINVAL);
@ -177,25 +185,10 @@ xs_dev_write(struct cdev *dev, struct uio *uio, int ioflag)
return (error);
}
static int
xs_dev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
static void
xs_dev_dtor(void *arg)
{
struct xs_dev_data *u;
#if 0 /* XXX figure out if equiv needed */
nonseekable_open(inode, filp);
#endif
u = malloc(sizeof(*u), M_XENSTORE, M_WAITOK|M_ZERO);
LIST_INIT(&u->transactions);
dev->si_drv1 = u;
return (0);
}
static int
xs_dev_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
{
struct xs_dev_data *u = dev->si_drv1;
struct xs_dev_data *u = arg;
struct xs_dev_transaction *trans, *tmp;
LIST_FOREACH_SAFE(trans, &u->transactions, list, tmp) {
@ -205,7 +198,21 @@ xs_dev_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
}
free(u, M_XENSTORE);
return (0);
}
static int
xs_dev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
{
struct xs_dev_data *u;
int error;
u = malloc(sizeof(*u), M_XENSTORE, M_WAITOK|M_ZERO);
LIST_INIT(&u->transactions);
error = devfs_set_cdevpriv(u, xs_dev_dtor);
if (error != 0)
free(u, M_XENSTORE);
return (error);
}
static struct cdevsw xs_dev_cdevsw = {
@ -213,7 +220,6 @@ static struct cdevsw xs_dev_cdevsw = {
.d_read = xs_dev_read,
.d_write = xs_dev_write,
.d_open = xs_dev_open,
.d_close = xs_dev_close,
.d_name = "xs_dev",
};
@ -262,8 +268,8 @@ xs_dev_attach(device_t dev)
{
struct cdev *xs_cdev;
xs_cdev = make_dev(&xs_dev_cdevsw, 0, UID_ROOT, GID_WHEEL, 0400,
"xen/xenstore");
xs_cdev = make_dev_credf(MAKEDEV_ETERNAL, &xs_dev_cdevsw, 0, NULL,
UID_ROOT, GID_WHEEL, 0400, "xen/xenstore");
if (xs_cdev == NULL)
return (EINVAL);