mirror_ubuntu-kernels/include
Patrick Ohly ac45f602ee net: infrastructure for hardware time stamping
The additional per-packet information (16 bytes for time stamps, 1
byte for flags) is stored for all packets in the skb_shared_info
struct. This implementation detail is hidden from users of that
information via skb_* accessor functions. A separate struct resp.
union is used for the additional information so that it can be
stored/copied easily outside of skb_shared_info.

Compared to previous implementations (reusing the tstamp field
depending on the context, optional additional structures) this
is the simplest solution. It does not extend sk_buff itself.

TX time stamping is implemented in software if the device driver
doesn't support hardware time stamping.

The new semantic for hardware/software time stamping around
ndo_start_xmit() is based on two assumptions about existing
network device drivers which don't support hardware time
stamping and know nothing about it:
 - they leave the new skb_shared_tx unmodified
 - the keep the connection to the originating socket in skb->sk
   alive, i.e., don't call skb_orphan()

Given that skb_shared_tx is new, the first assumption is safe.
The second is only true for some drivers. As a result, software
TX time stamping currently works with the bnx2 driver, but not
with the unmodified igb driver (the two drivers this patch series
was tested with).

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-15 22:43:34 -08:00
..
acpi ACPI: Enable bit 11 in _PDC to advertise hw coord 2009-02-07 00:41:14 -05:00
asm-arm
asm-frv net: new user space API for time stamping of incoming and outgoing packets 2009-02-15 22:43:33 -08:00
asm-generic Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-26 09:47:28 -08:00
asm-h8300
asm-m32r net: new user space API for time stamping of incoming and outgoing packets 2009-02-15 22:43:33 -08:00
asm-mn10300 net: new user space API for time stamping of incoming and outgoing packets 2009-02-15 22:43:33 -08:00
crypto crypto: shash - Fix tfm destruction 2009-02-05 16:51:25 +11:00
drm drm/i915: add fence register management to execbuf 2009-02-08 21:38:02 +10:00
keys
linux net: infrastructure for hardware time stamping 2009-02-15 22:43:34 -08:00
math-emu
media Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2009-02-02 19:26:06 -08:00
mtd headers_check fix: mtd/inftl-user.h 2009-01-31 00:13:34 +05:30
net Merge branch 'master' of /home/davem/src/GIT/linux-2.6/ 2009-02-14 23:12:00 -08:00
pcmcia
rdma net: replace __constant_{endian} uses in net headers 2009-02-14 22:58:35 -08:00
rxrpc
scsi [SCSI] iscsi_tcp: make padbuf non-static 2009-01-13 10:41:34 -06:00
sound headers_check fix: sound/hdsp.h 2009-01-31 00:13:56 +05:30
trace
video atyfb: fix CONFIG_ namespace violations 2009-02-05 12:56:48 -08:00
xen xen: add xenfs to allow usermode <-> Xen interaction 2009-01-08 08:30:59 -08:00
Kbuild