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Commit 2d38caba authored by Lennert Buytenhek's avatar Lennert Buytenhek Committed by Jeff Garzik
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[PATCH] ep93xx_eth: fix RX/TXstatus ring full handling



Ray Lehtiniemi reported that an incoming UDP packet flood can lock up
the ep93xx ethernet driver.  Herbert Valerio Riedel noted that due to
the way ep93xx_eth manages the RX/TXstatus rings, it cannot distinguish
a full ring from an empty one, and correctly suggested that this was
likely to be causing this lockup to occur.

Instead of looking at the hardware's RX/TXstatus ring write pointers
to determine when to stop reading from those rings, we should just check
every individual RX/TXstatus descriptor's valid bit instead, since there
is no other way to distinguish an empty ring from a full ring, and if
there is a descriptor waiting, we take the hit of reading the descriptor
from memory anyway.

Signed-off-by: default avatarLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent d5b9b787
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