Date: Wed, 8 Aug 2012 10:29:31 -0400 From: Andrew Boyer <aboyer@averesystems.com> To: freebsd-net@freebsd.org Subject: [patch] e1000 / lem handling of TSO defragmentation Message-ID: <5F36EE1D-89F0-4CF8-AB13-705847F2753F@averesystems.com>
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[-- Attachment #1 --]
Similar to what was done for em in r220254, this patch improves the error handling in lem when a TSO packet has too many segments to DMA. This improves the behavior when either call to bus_dmamap_load_mbuf_sg() returns ENOMEM. Although we don't need to go back and redo any offload calculation in lem, doing it this way reduces code duplication.
Comments welcome.
-Andrew
[-- Attachment #2 --]
Index: sys/dev/e1000/if_lem.c
===================================================================
--- sys/dev/e1000/if_lem.c (revision 239139)
+++ sys/dev/e1000/if_lem.c (working copy)
@@ -1525,8 +1525,9 @@
struct e1000_tx_desc *ctxd = NULL;
struct mbuf *m_head;
u32 txd_upper, txd_lower, txd_used, txd_saved;
- int error, nsegs, i, j, first, last = 0;
+ int error, nsegs, i, j, first, last = 0, remap = 1;
+retry:
m_head = *m_headp;
txd_upper = txd_lower = txd_used = txd_saved = 0;
@@ -1568,7 +1569,7 @@
* All other errors, in particular EINVAL, are fatal and prevent the
* mbuf chain from ever going through. Drop it and report error.
*/
- if (error == EFBIG) {
+ if (error == EFBIG && remap) {
struct mbuf *m;
m = m_defrag(*m_headp, M_DONTWAIT);
@@ -1580,18 +1581,16 @@
}
*m_headp = m;
- /* Try it again */
- error = bus_dmamap_load_mbuf_sg(adapter->txtag, map,
- *m_headp, segs, &nsegs, BUS_DMA_NOWAIT);
-
- if (error) {
- adapter->no_tx_dma_setup++;
- m_freem(*m_headp);
- *m_headp = NULL;
- return (error);
- }
+ /* Try it again, but only once */
+ remap = 0;
+ goto retry;
+ } else if (error == ENOMEM) {
+ adapter->no_tx_dma_setup++;
+ return (error);
} else if (error != 0) {
adapter->no_tx_dma_setup++;
+ m_freem(*m_headp);
+ *m_headp = NULL;
return (error);
}
[-- Attachment #3 --]
--------------------------------------------------
Andrew Boyer aboyer@averesystems.com
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