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authorLogan Gunthorpe <logang@deltatee.com>2017-08-03 12:19:45 -0600
committerJon Mason <jdmason@kudzu.us>2017-11-18 20:37:11 -0500
commitfa5ab66e36de56f7e40dad57780d53e059dced86 (patch)
tree7239deea35b4e92edd76ce65f7970b3ca077f248 /include/linux/ntb.h
parent980c41c86b37b6086ad758566b437cb1a469b4bc (diff)
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>
Diffstat (limited to 'include/linux/ntb.h')
-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);
}