2008-01-27 13:58:49

by Mark Brown

[permalink] [raw]
Subject: [PATCH] natsemi: Update locking documentation

The documentation regarding synchronisation at the head of the natsemi
driver was badly bitrotted so replace it with a general statement about
the techniques used which is less likely to bitrot.

Also remove the note saying these chips are uncommon - it makes little
difference but they were used in a number of laptops and at least one mass
market PCI ethernet card.

Signed-off-by: Mark Brown <[email protected]>
---
drivers/net/natsemi.c | 18 ++----------------
1 files changed, 2 insertions(+), 16 deletions(-)

diff --git a/drivers/net/natsemi.c b/drivers/net/natsemi.c
index c329a4f..0a3e604 100644
--- a/drivers/net/natsemi.c
+++ b/drivers/net/natsemi.c
@@ -203,22 +203,8 @@ skbuff at an offset of "+2", 16-byte aligning the IP header.
IIId. Synchronization

Most operations are synchronized on the np->lock irq spinlock, except the
-performance critical codepaths:
-
-The rx process only runs in the interrupt handler. Access from outside
-the interrupt handler is only permitted after disable_irq().
-
-The rx process usually runs under the netif_tx_lock. If np->intr_tx_reap
-is set, then access is permitted under spin_lock_irq(&np->lock).
-
-Thus configuration functions that want to access everything must call
- disable_irq(dev->irq);
- netif_tx_lock_bh(dev);
- spin_lock_irq(&np->lock);
-
-IV. Notes
-
-NatSemi PCI network controllers are very uncommon.
+recieve and transmit paths which are synchronised using a combination of
+hardware descriptor ownership, disabling interrupts and NAPI poll scheduling.

IVb. References

--
1.5.3.8


2008-01-30 08:49:22

by Jeff Garzik

[permalink] [raw]
Subject: Re: [PATCH] natsemi: Update locking documentation

Mark Brown wrote:
> The documentation regarding synchronisation at the head of the natsemi
> driver was badly bitrotted so replace it with a general statement about
> the techniques used which is less likely to bitrot.
>
> Also remove the note saying these chips are uncommon - it makes little
> difference but they were used in a number of laptops and at least one mass
> market PCI ethernet card.
>
> Signed-off-by: Mark Brown <[email protected]>
> ---
> drivers/net/natsemi.c | 18 ++----------------
> 1 files changed, 2 insertions(+), 16 deletions(-)

applied