powerpc/vas: Do not use default credits for receive window

System checkstops if RxFIFO overruns with more requests than the
maximum possible number of CRBs allowed in FIFO at any time. So
max credits value (rxattr.wcreds_max) is set and is passed to
vas_rx_win_open() by the the driver.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587017136.2275.1070.camel@hbabu-laptop

diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
index 3ef71209ff58df5171d1b1ddbee8733aad003360..4b5adf5218825ff035611c0c195a132a32bbd556 100644 (file)
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -772,7 +772,7 @@ static bool rx_win_args_valid(enum vas_cop_type cop,
        if (attr->rx_fifo_size > VAS_RX_FIFO_SIZE_MAX)
                return false;
 
-       if (attr->wcreds_max > VAS_RX_WCREDS_MAX)
+       if (!attr->wcreds_max)
                return false;
 
        if (attr->nx_win) {
@@ -877,7 +877,7 @@ struct vas_window *vas_rx_win_open(int vasid, enum vas_cop_type cop,
        rxwin->nx_win = rxattr->nx_win;
        rxwin->user_win = rxattr->user_win;
        rxwin->cop = cop;
-       rxwin->wcreds_max = rxattr->wcreds_max ?: VAS_WCREDS_DEFAULT;
+       rxwin->wcreds_max = rxattr->wcreds_max;
 
        init_winctx_for_rxwin(rxwin, rxattr, &winctx);
        init_winctx_regs(rxwin, &winctx);

diff --git a/arch/powerpc/platforms/powernv/vas.h b/arch/powerpc/platforms/powernv/vas.h
index 60bdda663750b41938bfe511c096a3aab220ea0d..a7143b16232f4f490b28d81f9d650b8eac6f98de 100644 (file)
--- a/arch/powerpc/platforms/powernv/vas.h
+++ b/arch/powerpc/platforms/powernv/vas.h
@@ -101,11 +101,9 @@
 /*
  * Initial per-process credits.
  * Max send window credits:    4K-1 (12-bits in VAS_TX_WCRED)
- * Max receive window credits: 64K-1 (16 bits in VAS_LRX_WCRED)
  *
  * TODO: Needs tuning for per-process credits
  */
-#define VAS_RX_WCREDS_MAX              ((64 << 10) - 1)
 #define VAS_TX_WCREDS_MAX              ((4 << 10) - 1)
 #define VAS_WCREDS_DEFAULT             (1 << 10)