[PATCH v2 2/3] doc: swiotlb: Document SWIOTLB areas parameter

["T.J. Mercier" <tjmercier@google.com>]

Commit 20347fca71a3 ("swiotlb: split up the global swiotlb lock") added
the ability to specify the number of SWIOTLB areas, but boot-options.rst
was not updated as part of that commit.

Reported-by: Michael Kelley <mhklinux@outlook.com>
Fixes: 20347fca71a3 ("swiotlb: split up the global swiotlb lock")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
---
 Documentation/arch/x86/x86_64/boot-options.rst | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/arch/x86/x86_64/boot-options.rst b/Documentation/arch/x86/x86_64/boot-options.rst
index a37139d1752f..18161657b301 100644
--- a/Documentation/arch/x86/x86_64/boot-options.rst
+++ b/Documentation/arch/x86/x86_64/boot-options.rst
@@ -287,9 +287,11 @@ iommu options only relevant to the AMD GART hardware IOMMU:
 iommu options only relevant to the software bounce buffering (SWIOTLB) IOMMU
 implementation:
 
-    swiotlb=<slots>[,force,noforce]
+    swiotlb=<slots>[,<areas>,force,noforce]
       <slots>
         Prereserve that many 2K slots for the software IO bounce buffering.
+      <areas>
+        Number of SWIOTLB areas with their own lock. Must be a power of 2.
       force
         Force all IO through the software TLB.
         Hardware IOMMU implementations can use SWIOTLB bounce buffering in
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog