>From: David Miller [mailto:davem@davemloft.net]
>Sent: Friday, September 10, 2010 1:22 PM
>To:
error27@gmail.com
>Cc: Rose, Gregory V; Kirsher, Jeffrey T; netdev@vger.kernel.org; kernel-
>janitors@vger.kernel.org
>Subject: Re: [patch] ixgbevf: potential NULL dereference on allocation
>failure
>
>It's trying to optimize out the "down/up" of the device, which needs
>to be done if we allocated a new TX ring.
>
>It also adjusts the semantics of the error return, in that if the
>TX ring re-sizing went OK but the RX resizing failed, it returns
>success.
>
>That's kind of crummy semantics, if any part fails we should unwind
>and return an error. So just do the necessary memory allocations
>first, and don't make any changes unless they all succeed.
>
>This code also seems to be incredibly racy. It allocates the new RING
>structure, and copies the existing entries over. Meanwhile the chip
>is still running and we're potentially processing these same ring
>entries, so by the time we actually assign adapter->{rx,tx}_ring
>pointers the contents could have changed.
>
>Probably the simplest thing to do is to structure this such that the
>chip is quiesced around the entire ring set operation, so something
>like:
