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authorShyam Sundar S K <ssundark@amd.com>2016-12-07 22:37:05 +0530
committerJon Mason <jdmason@kudzu.us>2016-12-23 16:10:35 -0500
commitb17faba03fc72091f4d040b879def004316952ec (patch)
tree656172d04639633675a0b2b419083ecf9d675a14
parent872deb21038e90903a40ab6a29b9d0652a6ebc8d (diff)
downloadlinux-stericsson-b17faba03fc72091f4d040b879def004316952ec.tar.gz
ntb_transport: Limit memory windows based on available, scratchpads
When the underlying NTB H/W driver advertises more memory windows than the number of scratchpads available to setup MW's, it is likely that we may end up filling the remaining memory windows with garbage. So to avoid that, lets limit the memory windows that transport driver can setup based on the available scratchpads. Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com> Acked-by: Allen Hubbe <Allen.Hubbe@dell.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
-rw-r--r--drivers/ntb/ntb_transport.c28
1 files changed, 16 insertions, 12 deletions
diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 4eb8adb34508..9b791cb33c19 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -66,6 +66,7 @@
#define NTB_TRANSPORT_VER "4"
#define NTB_TRANSPORT_NAME "ntb_transport"
#define NTB_TRANSPORT_DESC "Software Queue-Pair Transport over NTB"
+#define NTB_TRANSPORT_MIN_SPADS (MW0_SZ_HIGH + 2)
MODULE_DESCRIPTION(NTB_TRANSPORT_DESC);
MODULE_VERSION(NTB_TRANSPORT_VER);
@@ -242,9 +243,6 @@ enum {
NUM_MWS,
MW0_SZ_HIGH,
MW0_SZ_LOW,
- MW1_SZ_HIGH,
- MW1_SZ_LOW,
- MAX_SPAD,
};
#define dev_client_dev(__dev) \
@@ -811,7 +809,7 @@ static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
{
struct ntb_transport_qp *qp;
u64 qp_bitmap_alloc;
- int i;
+ unsigned int i, count;
qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
@@ -831,7 +829,8 @@ static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
* goes down, blast them now to give them a sane value the next
* time they are accessed
*/
- for (i = 0; i < MAX_SPAD; i++)
+ count = ntb_spad_count(nt->ndev);
+ for (i = 0; i < count; i++)
ntb_spad_write(nt->ndev, i, 0);
}
@@ -1064,17 +1063,12 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
{
struct ntb_transport_ctx *nt;
struct ntb_transport_mw *mw;
- unsigned int mw_count, qp_count;
+ unsigned int mw_count, qp_count, spad_count, max_mw_count_for_spads;
u64 qp_bitmap;
int node;
int rc, i;
mw_count = ntb_mw_count(ndev);
- if (ntb_spad_count(ndev) < (NUM_MWS + 1 + mw_count * 2)) {
- dev_err(&ndev->dev, "Not enough scratch pad registers for %s",
- NTB_TRANSPORT_NAME);
- return -EIO;
- }
if (ntb_db_is_unsafe(ndev))
dev_dbg(&ndev->dev,
@@ -1090,8 +1084,18 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
return -ENOMEM;
nt->ndev = ndev;
+ spad_count = ntb_spad_count(ndev);
+
+ /* Limit the MW's based on the availability of scratchpads */
+
+ if (spad_count < NTB_TRANSPORT_MIN_SPADS) {
+ nt->mw_count = 0;
+ rc = -EINVAL;
+ goto err;
+ }
- nt->mw_count = mw_count;
+ max_mw_count_for_spads = (spad_count - MW0_SZ_HIGH) / 2;
+ nt->mw_count = min(mw_count, max_mw_count_for_spads);
nt->mw_vec = kzalloc_node(mw_count * sizeof(*nt->mw_vec),
GFP_KERNEL, node);