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: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Allen Hubbe <Allen.Hubbe@dell.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
This commit is contained in:
Logan Gunthorpe 2017-08-03 12:19:45 -06:00 committed by Jon Mason
parent 980c41c86b
commit fa5ab66e36

View File

@ -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);
}