FAILED: patch "[PATCH] of: address: Preserve the flags portion on 1:1 dma-ranges" failed to apply to 5.4-stable tree

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 7f05e20b989ac33c9c0f8c2028ec0a566493548f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024122347-fiscally-slacks-e686@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7f05e20b989ac33c9c0f8c2028ec0a566493548f Mon Sep 17 00:00:00 2001
From: Andrea della Porta <[email protected]>
Date: Sun, 24 Nov 2024 11:05:37 +0100
Subject: [PATCH] of: address: Preserve the flags portion on 1:1 dma-ranges
mapping

A missing or empty dma-ranges in a DT node implies a 1:1 mapping for dma translations. In this specific case, the current behaviour is to zero out the entire specifier so that the translation could be carried on as an offset from zero. This includes address specifier that has flags (e.g. PCI ranges).

Once the flags portion has been zeroed, the translation chain is broken since the mapping functions will check the upcoming address specifier against mismatching flags, always failing the 1:1 mapping and its entire purpose of always succeeding.

Set to zero only the address portion while passing the flags through.

index c5b925ac469f..5b7ee3ed5296 100644
@@ -459,7 +459,8 @@ static int of_translate_one(const struct device_node *parent, const struct of_bu
 	}
 	if (ranges == NULL || rlen == 0) {
 		offset = of_read_number(addr, na);
-		memset(addr, 0, pna * 4);
+		/* set address to zero, pass flags through */
+		memset(addr + pbus->flag_cells, 0, (pna - pbus->flag_cells) * 4);
 		pr_debug("empty ranges; 1:1 translation\n");
 		goto finish;
 	}