From fa5ab66e36de56f7e40dad57780d53e059dced86 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Thu, 3 Aug 2017 12:19:45 -0600 Subject: 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 Acked-by: Allen Hubbe Signed-off-by: Jon Mason --- include/linux/ntb.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'include/linux/ntb.h') 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); } -- cgit