diff --git a/pkgs/os-specific/linux/kernel-headers/default.nix b/pkgs/os-specific/linux/kernel-headers/default.nix
index d07c9073e6a1..5b2fb62cb95e 100644
--- a/pkgs/os-specific/linux/kernel-headers/default.nix
+++ b/pkgs/os-specific/linux/kernel-headers/default.nix
@@ -93,6 +93,9 @@ in {
       };
       patches = [
          ./no-relocs.patch # for building x86 kernel headers on non-ELF platforms
+
+         # 5.19 backport. Can be removed on update.
+         ./restore-__bitwise__.patch
       ];
     };
 }
diff --git a/pkgs/os-specific/linux/kernel-headers/restore-__bitwise__.patch b/pkgs/os-specific/linux/kernel-headers/restore-__bitwise__.patch
new file mode 100644
index 000000000000..67d2af8fc3bb
--- /dev/null
+++ b/pkgs/os-specific/linux/kernel-headers/restore-__bitwise__.patch
@@ -0,0 +1,15 @@
+https://github.com/torvalds/linux/commit/caa28984163cb63ea0be4cb8dbf05defdc7303f9
+
+Fixes openiscsi build.
+--- a/include/uapi/linux/types.h
++++ b/include/uapi/linux/types.h
+@@ -26,6 +26,9 @@
+ #define __bitwise
+ #endif
+ 
++/* The kernel doesn't use this legacy form, but user space does */
++#define __bitwise__ __bitwise
++
+ typedef __u16 __bitwise __le16;
+ typedef __u16 __bitwise __be16;
+ typedef __u32 __bitwise __le32;