Author: adrian
Date: Thu Jul 8 14:59:32 2010
New Revision: 209807
URL: http://svn.freebsd.org/changeset/base/209807
Log:
Address PR kern/148307 - fix if_ath TX mbuf alignment/size constraint checks
The existing code only checked the alignment of the first mbuf and
didn't enforce the size constraints.
This commit introduces a simple function to check the alignment and
size of all mbufs in the list. This fixes the initial issue in the
PR.
PR: kern/148307
Reviewed by: gonzo@
Modified:
head/sys/mips/atheros/if_arge.c
Modified: head/sys/mips/atheros/if_arge.c
==============================================================================
--- head/sys/mips/atheros/if_arge.c Thu Jul 8 14:56:42 2010
(r209806)
+++ head/sys/mips/atheros/if_arge.c Thu Jul 8 14:59:32 2010
(r209807)
@@ -834,6 +834,28 @@ arge_init_locked(struct arge_softc *sc)
}
/*
+ * Return whether the mbuf chain is correctly aligned
+ * for the arge TX engine.
+ *
+ * The TX engine requires each fragment to be aligned to a
+ * 4 byte boundary and the size of each fragment except
+ * the last to be a multiple of 4 bytes.
+ */
+static int
+arge_mbuf_chain_is_tx_aligned(struct mbuf *m0)
+{
+ struct mbuf *m;
+
+ for (m = m0; m != NULL; m = m->m_next) {
+ if((mtod(m, intptr_t) & 3) != 0)
+ return 0;
+ if ((m->m_next != NULL) && ((m->m_len & 0x03) != 0))
+ return 0;
+ }
+ return 1;
+}
+
+/*
* Encapsulate an mbuf chain in a descriptor by coupling the mbuf data
* pointers to the fragment pointers.
*/
@@ -853,7 +875,7 @@ arge_encap(struct arge_softc *sc, struct
* even 4 bytes
*/
m = *m_head;
- if((mtod(m, intptr_t) & 3) != 0) {
+ if (! arge_mbuf_chain_is_tx_aligned(m)) {
m = m_defrag(*m_head, M_DONTWAIT);
if (m == NULL) {
*m_head = NULL;
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