means we're in interrupt context. Since we can be called from a network
hardware interrupt, we could corrupt the protocol queues we try to drain
them at that time.
called when devices attach, take two.
Note that it is necessary that mbinit() NOT allocate memory, since it
is called before mb_map is created. This is not a problem with the
pool allocator that is now used for mbufs and mbuf clusters.
The read/write system calls return ssize_t because -1 is used to indicate
error, therefore the transfer size MUST be limited to SSIZE_MAX, otherwise
garbage can be returned to the user.
There is NO change from existing behavior here, only a more precise
definition of that the semantics are, except in the Alpha case, where
the full SSIZE_MAX transfer size can now be realized (ssize_t is 64-bit
on the Alpha).
The read/write system calls return ssize_t because -1 is used to indicate
error, therefore the transfer size MUST be limited to SSIZE_MAX, otherwise
garbage can be returned to the user.
There is NO change from existing behavior here, only a more precise
definition of that the semantics are, except in the Alpha case, where
the full SSIZE_MAX transfer size can now be realized (ssize_t is 64-bit
on the Alpha).
- If either an alloc or release function is provided, make sure both are
provided, otherwise panic, as this is a fatal error.
- If using the default allocator, default the pool pagesz to PAGE_SIZE,
since that is the granularity of the default allocator's mechanism.
- In the default allocator, use new functions:
uvm_km_alloc_poolpage()/uvm_km_free_poolpage(), or
kmem_alloc_poolpage()/kmem_free_poolpage()
rather than doing it here. These functions may use pmap hooks to
provide alternate methods of mapping pool pages.
- pread() (#173) and pwrite() (#174), which are defined by XPG4.2. System
call numbers match Solaris.
- preadv() (#289) and pwritev() (#290), which are the positional cousins
of readv() and writev(), but not defined by any standard.
thorpej