NTB: Skip db_valid validation writing DB link bit

In ntb_poll_link, we are intentionally writing the link bit, which is
absent from db_valid_mask.  Don't panic on a kassert when we do so.

The Linux version of this (dual BSD/GPL) driver has the db_valid_mask
assertions in callers of db_iowrite() rather than db_iowrite() itself;
it skips the assertions in the equivalent of ntb_poll_link().  Rather
than duplicating the assertions in every caller, add a db_iowrite_raw()
that doesn't check and use it from ntb_poll_link().

Suggested by:	kassert_panic
Sponsored by:	EMC / Isilon Storage Division

diff --git a/sys/dev/ntb/ntb_hw/ntb_hw.c b/sys/dev/ntb/ntb_hw/ntb_hw.c
index e918d263ea59ab9e3d4e6021ea1d2133f0e09092..480d54b0c7d18084d4a63712b7d7d7a61ea81aeb 100644 (file)
--- a/sys/dev/ntb/ntb_hw/ntb_hw.c
+++ b/sys/dev/ntb/ntb_hw/ntb_hw.c
@@ -283,7 +283,8 @@ static void ntb_interrupt(struct ntb_softc *, uint32_t vec);
 static void ndev_vec_isr(void *arg);
 static void ndev_irq_isr(void *arg);
 static inline uint64_t db_ioread(struct ntb_softc *, uint64_t regoff);
-static inline void db_iowrite(struct ntb_softc *, uint64_t regoff, uint64_t val);
+static inline void db_iowrite(struct ntb_softc *, uint64_t regoff, uint64_t);
+static inline void db_iowrite_raw(struct ntb_softc *, uint64_t regoff, uint64_t);
 static int ntb_create_msix_vec(struct ntb_softc *ntb, uint32_t num_vectors);
 static void ntb_free_msix_vec(struct ntb_softc *ntb);
 static struct ntb_hw_info *ntb_get_device_info(uint32_t device_id);
@@ -994,6 +995,12 @@ db_iowrite(struct ntb_softc *ntb, uint64_t regoff, uint64_t val)
 
        if (regoff == ntb->self_reg->db_mask)
                DB_MASK_ASSERT(ntb, MA_OWNED);
+       db_iowrite_raw(ntb, regoff, val);
+}
+
+static inline void
+db_iowrite_raw(struct ntb_softc *ntb, uint64_t regoff, uint64_t val)
+{
 
        if (ntb->type == NTB_ATOM) {
                ntb_reg_write(8, regoff, val);
@@ -1875,7 +1882,7 @@ ntb_poll_link(struct ntb_softc *ntb)
                ntb->ntb_ctl = ntb_cntl;
                ntb->lnk_sta = ntb_reg_read(4, ntb->reg->lnk_sta);
        } else {
-               db_iowrite(ntb, ntb->self_reg->db_bell, ntb->db_link_mask);
+               db_iowrite_raw(ntb, ntb->self_reg->db_bell, ntb->db_link_mask);
 
                reg_val = pci_read_config(ntb->device, ntb->reg->lnk_sta, 2);
                if (reg_val == ntb->lnk_sta)