Commit fa5ab66e authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Jon Mason
Browse files

NTB: Add check and comment for link up to mw_count() and mw_get_align()

Adds a comment and a check to ntb_mw_get_align() so that it always fails
if the function is called before the link is up.

Also adds a comment to ntb_mw_count() to note that it may return 0 if
it is called before the link is up.

This is to prevent accidental mis-use in clients that are testing
on hardware that this doesn't matter for.
Signed-off-by: default avatarLogan Gunthorpe <>
Acked-by: default avatarAllen Hubbe <>
Signed-off-by: default avatarJon Mason <>
parent 980c41c8
......@@ -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,
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