net: qlogic: Fix error paths in ql_alloc_large_buffers()

ql_alloc_large_buffers() has the usual RX buffer allocation
loop where it allocates skbs and maps them for DMA.  It also
treats failure as a fatal error.

There are (at least) three bugs in the error paths:

1. ql_free_large_buffers() assumes that the lrg_buf[] entry for the
first buffer that couldn't be allocated will have .skb == NULL.
But the qla_buf[] array is not zero-initialised.

2. ql_free_large_buffers() DMA-unmaps all skbs in lrg_buf[].  This is
incorrect for the last allocated skb, if DMA mapping failed.

3. Commit 1acb8f2a7a9f ("net: qlogic: Fix memory leak in
ql_alloc_large_buffers") added a direct call to dev_kfree_skb_any()
after the skb is recorded in lrg_buf[], so ql_free_large_buffers()
will double-free it.

The bugs are somewhat inter-twined, so fix them all at once:

* Clear each entry in qla_buf[] before attempting to allocate
  an skb for it.  This goes half-way to fixing bug 1.
* Set the .skb field only after the skb is DMA-mapped.  This
  fixes the rest.

Fixes: 1357bfcf7106 ("qla3xxx: Dynamically size the rx buffer queue ...")
Fixes: 0f8ab89e825f ("qla3xxx: Check return code from pci_map_single() ...")
Fixes: 1acb8f2a7a9f ("net: qlogic: Fix memory leak in ql_alloc_large_buffers")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/qlogic/qla3xxx.c b/drivers/net/ethernet/qlogic/qla3xxx.c
index b4b8ba0..986f265 100644 (file)
--- a/drivers/net/ethernet/qlogic/qla3xxx.c
+++ b/drivers/net/ethernet/qlogic/qla3xxx.c
@@ -2756,6 +2756,9 @@ static int ql_alloc_large_buffers(struct ql3_adapter *qdev)
        int err;
 
        for (i = 0; i < qdev->num_large_buffers; i++) {
+               lrg_buf_cb = &qdev->lrg_buf[i];
+               memset(lrg_buf_cb, 0, sizeof(struct ql_rcv_buf_cb));
+
                skb = netdev_alloc_skb(qdev->ndev,
                                       qdev->lrg_buffer_len);
                if (unlikely(!skb)) {
@@ -2766,11 +2769,7 @@ static int ql_alloc_large_buffers(struct ql3_adapter *qdev)
                        ql_free_large_buffers(qdev);
                        return -ENOMEM;
                } else {
-
-                       lrg_buf_cb = &qdev->lrg_buf[i];
-                       memset(lrg_buf_cb, 0, sizeof(struct ql_rcv_buf_cb));
                        lrg_buf_cb->index = i;
-                       lrg_buf_cb->skb = skb;
                        /*
                         * We save some space to copy the ethhdr from first
                         * buffer
@@ -2792,6 +2791,7 @@ static int ql_alloc_large_buffers(struct ql3_adapter *qdev)
                                return -ENOMEM;
                        }
 
+                       lrg_buf_cb->skb = skb;
                        dma_unmap_addr_set(lrg_buf_cb, mapaddr, map);
                        dma_unmap_len_set(lrg_buf_cb, maplen,
                                          qdev->lrg_buffer_len -