2 files changed, 7 insertions, 2 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index be6ba33d4ff1..8f441dab0396 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3124,7 +3124,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         controller if no parameter or 1 is given or disable
                         it if 0 is given (See Documentation/cgroups/memory.txt)
 
-        swiotlb=        [IA-64] Number of I/O TLB slabs
+        swiotlb=        [ARM,IA-64,PPC,MIPS,X86]
+                        Format: { <int> | force }
+                        <int> -- Number of I/O TLB slabs
+                        force -- force using of bounce buffers even if they
+                                 wouldn't be automatically used by the kernel
 
         switches=       [HW,M68k]
 
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 615f3de4b5ce..2e1c102759ce 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -510,7 +510,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 
 not_found:
         spin_unlock_irqrestore(&io_tlb_lock, flags);
-        dev_warn(hwdev, "swiotlb buffer is full\n");
+        if (printk_ratelimit())
+                dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size);
         return SWIOTLB_MAP_ERROR;
 found:
         spin_unlock_irqrestore(&io_tlb_lock, flags);