Benjamin Herrenschmidt wrote:
net: Add __napi_synchronize() to sync with napi poll
The EMAC driver which needs to handle multiple devices with one
NAPI instance implements its own per-channel disable bit. However,
when setting such a bit, it needs to synchronize with the poller
(that is make sure that any pending poller instance has completed,
or is started late enough to see that disable bit).
This implements a low level __napi_synchronize() function to acheive
that. The underscores are to emphasis the low level aspect of it and
to discourage driver writers who don't know what they are doing to
use it (to please DaveM :-)
Signed-off-by: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
---
Switched to do a cpu_relax() spin instead and only on SMP. Not that
we have an smp_mb() in there which synchronize_irq() lacks. I believe
this is a bug in synchronize_irq() which I'll handle separately.
Note: unfortunately, Jeff already picked up the EMAC patch without
waiting for this to be sorted out (oops...). So if you agree with
this patch, it would be nice to have it go in quickly or maybe via
Jeff's tree to avoid breakage ? Not terribly important tho.
Sorry, I thought that was the way everybody was headed. With the driver
broken /anyway/, I just sorta threw it into the pile of fixes.
It's upstream now, so let me know if you want to revert or move forward
from here...
Jeff
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