swiotlb: panic if nslabs is too small

Panic on purpose if nslabs is too small, in order to sync with the remap
retry logic.

In addition, print the number of bytes for tlb alloc failure.

Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index fd21f4162f4b315c5c0b08b18fd4b6021b4a6086..1758b724c7a8da5e1fe8532169c4786e68523d54 100644 (file)
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -242,6 +242,9 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
        if (swiotlb_force_disable)
                return;
 
+       if (nslabs < IO_TLB_MIN_SLABS)
+               panic("%s: nslabs = %lu too small\n", __func__, nslabs);
+
        /*
         * By default allocate the bounce buffer memory from low memory, but
         * allow to pick a location everywhere for hypervisors with guest
@@ -254,7 +257,8 @@ retry:
        else
                tlb = memblock_alloc_low(bytes, PAGE_SIZE);
        if (!tlb) {
-               pr_warn("%s: failed to allocate tlb structure\n", __func__);
+               pr_warn("%s: Failed to allocate %zu bytes tlb structure\n",
+                       __func__, bytes);
                return;
        }