interrupt sleeps. Rather, unmasked signals interrupt restarts and can
either interrupt the system call by having it return EINTR in userland or
force the system call to be restarted.
- Don't claim that the mutex is atomically reacquired when a cv_wait
routine returns. There's nothing atomic or magical about the lock
reacquire. The only magic is that we atomically drop the lock by
placing the thread on the sleep queue before dropping the lock.
- Markup sx_unlock() as a function rather than saying it is a macro.
The macro part is an implementation detail, and all the other sx_*lock()
functions are actually macros, too.
- Use the same style as rwlock(9) and mutex(9) to markup sx_assert() and
SX_SYSINIT() with respect to headers and kernel options.
- Add a missing MLINK.
<sys/extattr.h> to <ufs/ufs/extattr.h>. Move description
of extended attributes in UFS from man9/extattr.9 to
man5/fs.5.
Note that restore will not compile until <sys/extattr.h>
and <ufs/ufs/extattr.h> have been updated.
Suggested by: Robert Watson
o uniform the driver_intr_t parameter name to 'ithread'
o delete any reference to INTR_FAST
o document a bit the difference between the filter and ithread
argument
Reviewed by: mdoc-police (ru)
- the issues with wakeup_one are due to address space clashes between
unrelated groups of threads.
- sleep() was removed in FreeBSD 2.2.
- date the page today, not 4 days ago.
- replace grammatically correct "woken" with "woken up" for
consistency with the function name.
attribute. Also define some macros to manipulate one of these
structures. Explain their use in the extattr.9 manual page.
The next step will be to make a sweep through the kernel replacing
the old pointer manipulation code. To get an idea of how they would
be used, the ffs_findextattr() function in ufs/ffs/ffs_vnops.c is
currently written as follows:
/*
* Vnode operating to retrieve a named extended attribute.
*
* Locate a particular EA (nspace:name) in the area (ptr:length), and return
* the length of the EA, and possibly the pointer to the entry and to the data.
*/
static int
ffs_findextattr(u_char *ptr, u_int length, int nspace, const char *name,
u_char **eap, u_char **eac)
{
u_char *p, *pe, *pn, *p0;
int eapad1, eapad2, ealength, ealen, nlen;
uint32_t ul;
pe = ptr + length;
nlen = strlen(name);
for (p = ptr; p < pe; p = pn) {
p0 = p;
bcopy(p, &ul, sizeof(ul));
pn = p + ul;
/* make sure this entry is complete */
if (pn > pe)
break;
p += sizeof(uint32_t);
if (*p != nspace)
continue;
p++;
eapad2 = *p++;
if (*p != nlen)
continue;
p++;
if (bcmp(p, name, nlen))
continue;
ealength = sizeof(uint32_t) + 3 + nlen;
eapad1 = 8 - (ealength % 8);
if (eapad1 == 8)
eapad1 = 0;
ealength += eapad1;
ealen = ul - ealength - eapad2;
p += nlen + eapad1;
if (eap != NULL)
*eap = p0;
if (eac != NULL)
*eac = p;
return (ealen);
}
return(-1);
}
After applying the structure and macros, it would look like this:
/*
* Vnode operating to retrieve a named extended attribute.
*
* Locate a particular EA (nspace:name) in the area (ptr:length), and return
* the length of the EA, and possibly the pointer to the entry and to the data.
*/
static int
ffs_findextattr(u_char *ptr, u_int length, int nspace, const char *name,
u_char **eapp, u_char **eac)
{
struct extattr *eap, *eaend;
eaend = (struct extattr *)(ptr + length);
for (eap = (struct extattr *)ptr; eap < eaend; eap = EXTATTR_NEXT(eap)){
/* make sure this entry is complete */
if (EXTATTR_NEXT(eap) > eaend)
break;
if (eap->ea_namespace != nspace ||
eap->ea_namelength != length ||
bcmp(eap->ea_name, name, length))
continue;
if (eapp != NULL)
*eapp = eap;
if (eac != NULL)
*eac = EXTATTR_CONTENT(eap);
return (EXTATTR_CONTENT_SIZE(eap));
}
return(-1);
}
Not only is it considerably shorter, but it hopefully more readable :-)
want an equivalent of DELAY(9) that sleeps instead of spins. It accepts
a wmesg and a timeout and is not interrupted by signals. It uses a private
wait channel that should never be woken up by wakeup(9) or wakeup_one(9).
Glanced at by: phk
transition to mbuma (FreeBSD 5.3) and the fact that mbufs are now limited
almost entirely to packet storage, with straight UMA zones being used for
most other network data types.
Apart from minor cleanup of the text, it should document
in reasonable detail what the status of the code is.
RELENG_6 has some minor differences there in the way automatic
loading/unloading is handled, but hopefully this should be
fixed by MFC time.
The examples come from Max Laier and Sam Leffler.
MFC after: 1 week
Approved by: gnn
Add a new function hashinit_flags() which allows NOT-waiting
for memory (or waiting). The old hashinit() function now
calls hashinit_flags(..., HASH_WAITOK);
