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authorUrsula Braun <ubraun@linux.vnet.ibm.com>2018-02-09 11:03:49 +0100
committerDavid S. Miller <davem@davemloft.net>2018-02-09 14:30:23 -0500
commit89271c65edd599207dd982007900506283c90ae3 (patch)
tree8914755732ad1d2d5eca6c0be6d64d05806eb23d
parent0bf7800f1799b5b1fd7d4f024e9ece53ac489011 (diff)
s390/qeth: fix underestimated count of buffer elements
For a memory range/skb where the last byte falls onto a page boundary (ie. 'end' is of the form xxx...xxx001), the PFN_UP() part of the calculation currently doesn't round up to the next PFN due to an off-by-one error. Thus qeth believes that the skb occupies one page less than it actually does, and may select a IO buffer that doesn't have enough spare buffer elements to fit all of the skb's data. HW detects this as a malformed buffer descriptor, and raises an exception which then triggers device recovery. Fixes: 2863c61334aa ("qeth: refactor calculation of SBALE count") Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com> Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/s390/net/qeth_core.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index db42107bf2f5..c33fbc4c2e91 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -846,7 +846,7 @@ struct qeth_trap_id {
*/
static inline int qeth_get_elements_for_range(addr_t start, addr_t end)
{
- return PFN_UP(end - 1) - PFN_DOWN(start);
+ return PFN_UP(end) - PFN_DOWN(start);
}
static inline int qeth_get_micros(void)

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