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-rw-r--r--include/linux/ntb.h8
1 files changed, 6 insertions, 2 deletions
diff --git a/include/linux/ntb.h b/include/linux/ntb.h
index 609e232c00da..47f2966cfd7f 100644
--- a/include/linux/ntb.h
+++ b/include/linux/ntb.h
@@ -730,7 +730,8 @@ static inline int ntb_link_disable(struct ntb_dev *ntb)
* Hardware and topology may support a different number of memory windows.
* Moreover different peer devices can support different number of memory
* windows. Simply speaking this method returns the number of possible inbound
- * memory windows to share with specified peer device.
+ * memory windows to share with specified peer device. Note: this may return
+ * zero if the link is not up yet.
*
* Return: the number of memory windows.
*/
@@ -751,7 +752,7 @@ static inline int ntb_mw_count(struct ntb_dev *ntb, int pidx)
* Get the alignments of an inbound memory window with specified index.
* NULL may be given for any output parameter if the value is not needed.
* The alignment and size parameters may be used for allocation of proper
- * shared memory.
+ * shared memory. Note: this must only be called when the link is up.
*
* Return: Zero on success, otherwise a negative error number.
*/
@@ -760,6 +761,9 @@ static inline int ntb_mw_get_align(struct ntb_dev *ntb, int pidx, int widx,
resource_size_t *size_align,
resource_size_t *size_max)
{
+ if (!(ntb_link_is_up(ntb, NULL, NULL) & (1 << pidx)))
+ return -ENOTCONN;
+
return ntb->ops->mw_get_align(ntb, pidx, widx, addr_align, size_align,
size_max);
}