Revision db61ecc3352d72513c1b07805bd6f760e30c001b authored by Tommy S. Christensen on 19 May 2005, 19:46:59 UTC, committed by David S. Miller on 19 May 2005, 19:46:59 UTC
This bug causes: assertion (!atomic_read(&sk->sk_rmem_alloc)) failed at net/netlink/af_netlink.c (122) What's happening is that: 1) The skb is sent to socket 1. 2) Someone does a recvmsg on socket 1 and drops the ref on the skb. Note that the rmalloc is not returned at this point since the skb is still referenced. 3) The same skb is now sent to socket 2. This version of the fix resurrects the skb_orphan call that was moved out, last time we had 'shared-skb troubles'. It is practically a no-op in the common case, but still prevents the possible race with recvmsg. Signed-off-by: Tommy S. Christensen <tommy.christensen@tpack.net> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
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zorro.txt
Writing Device Drivers for Zorro Devices
----------------------------------------
Written by Geert Uytterhoeven <geert@linux-m68k.org>
Last revised: September 5, 2003
1. Introduction
---------------
The Zorro bus is the bus used in the Amiga family of computers. Thanks to
AutoConfig(tm), it's 100% Plug-and-Play.
There are two types of Zorro busses, Zorro II and Zorro III:
- The Zorro II address space is 24-bit and lies within the first 16 MB of the
Amiga's address map.
- Zorro III is a 32-bit extension of Zorro II, which is backwards compatible
with Zorro II. The Zorro III address space lies outside the first 16 MB.
2. Probing for Zorro Devices
----------------------------
Zorro devices are found by calling `zorro_find_device()', which returns a
pointer to the `next' Zorro device with the specified Zorro ID. A probe loop
for the board with Zorro ID `ZORRO_PROD_xxx' looks like:
struct zorro_dev *z = NULL;
while ((z = zorro_find_device(ZORRO_PROD_xxx, z))) {
if (!zorro_request_region(z->resource.start+MY_START, MY_SIZE,
"My explanation"))
...
}
`ZORRO_WILDCARD' acts as a wildcard and finds any Zorro device. If your driver
supports different types of boards, you can use a construct like:
struct zorro_dev *z = NULL;
while ((z = zorro_find_device(ZORRO_WILDCARD, z))) {
if (z->id != ZORRO_PROD_xxx1 && z->id != ZORRO_PROD_xxx2 && ...)
continue;
if (!zorro_request_region(z->resource.start+MY_START, MY_SIZE,
"My explanation"))
...
}
3. Zorro Resources
------------------
Before you can access a Zorro device's registers, you have to make sure it's
not yet in use. This is done using the I/O memory space resource management
functions:
request_mem_region()
release_mem_region()
Shortcuts to claim the whole device's address space are provided as well:
zorro_request_device
zorro_release_device
4. Accessing the Zorro Address Space
------------------------------------
The address regions in the Zorro device resources are Zorro bus address
regions. Due to the identity bus-physical address mapping on the Zorro bus,
they are CPU physical addresses as well.
The treatment of these regions depends on the type of Zorro space:
- Zorro II address space is always mapped and does not have to be mapped
explicitly using z_ioremap().
Conversion from bus/physical Zorro II addresses to kernel virtual addresses
and vice versa is done using:
virt_addr = ZTWO_VADDR(bus_addr);
bus_addr = ZTWO_PADDR(virt_addr);
- Zorro III address space must be mapped explicitly using z_ioremap() first
before it can be accessed:
virt_addr = z_ioremap(bus_addr, size);
...
z_iounmap(virt_addr);
5. References
-------------
linux/include/linux/zorro.h
linux/include/asm-{m68k,ppc}/zorro.h
linux/include/linux/zorro_ids.h
linux/drivers/zorro
/proc/bus/zorro
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