On Wed, Jan 03, 2018 at 10:28:31AM -0500, David Miller wrote:

From: David Miller <davem@davemloft.net>
Date: Wed, 03 Jan 2018 10:26:06 -0500 (EST)

quoted

From: Neil Horman <redacted>
Date: Wed, 3 Jan 2018 10:13:33 -0500

quoted

Thats exactly what this patch does, instead of creating a second loop to
traverse all the emptied ring buffers, now I:

1) Pre-allocate a new skb when I know I'm going to receive the in-place skb
2) Map the skb into the appropriate dma device domain
3) If (1) and (2) succede, then I swap the newly allocate skb and dma address
with the old one and recieve the old into the network stack
4) If (1) or (2) fail, then I goto clear_complete, which leaves the old skb and
dma address in place, sets the buffer status back to 0 (indicating completion),
and write the new ring status back to the hardware

This is what you wanted, a pre-allocate and swap-if-successful, recycle-if-not
approach, rather than the leave-a-hole-in-the-ring approach that is there
currently, no?  Or did I miss something else?

I misread the code sorry, you're absolutely right.

I'll apply this patch, thanks Neil. :)

Hmmm, maybe we need a V3 after all :)

  CC [M]  drivers/net/ethernet/3com/3c59x.o
drivers/net/ethernet/3com/3c59x.c: In function ‘boomerang_rx’:
drivers/net/ethernet/3com/3c59x.c:2605:13: warning: unused variable ‘dma’ [-Wunused-variable]
  dma_addr_t dma;
             ^~~

Thats....odd, I built it twice here, and it didn't bomb out.  I must not have
-Werror enabled, apologies.  I'll respin
Neil