xprtrdma: Fix backchannel allocation of extra rpcrdma_reps

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The backchannel code uses rpcrdma_recv_buffer_put to add new reps
to the free rep list. This also decrements rb_recv_count, which
spoofs the receive overrun logic in rpcrdma_buffer_get_rep.

Commit 9b06688bc3 ("xprtrdma: Fix additional uses of
spin_lock_irqsave(rb_lock)") replaced the original open-coded
list_add with a call to rpcrdma_recv_buffer_put(), but then a year
later, commit 05c974669e ("xprtrdma: Fix receive buffer
accounting") added rep accounting to rpcrdma_recv_buffer_put.
It was an oversight to let the backchannel continue to use this
function.

The fix this, let's combine the "add to free list" logic with
rpcrdma_create_rep.

Also, do not allocate RPCRDMA_MAX_BC_REQUESTS rpcrdma_reps in
rpcrdma_buffer_create and then allocate additional rpcrdma_reps in
rpcrdma_bc_setup_reps. Allocating the extra reps during backchannel
set-up is sufficient.

Fixes: 05c974669e ("xprtrdma: Fix receive buffer accounting")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

...

This commit is contained in:

Chuck Lever 2017-12-14 20:56:09 -05:00 • committed by Anna Schumaker

parent 03ac1a76ce

commit d698c4a02e

3 changed files with 22 additions and 24 deletions

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12

net/sunrpc/xprtrdma/backchannel.c

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32

net/sunrpc/xprtrdma/verbs.c

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2

net/sunrpc/xprtrdma/xprt_rdma.h

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