FAILED: patch "[PATCH] btrfs: allow swap activation to be interruptible" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 9a45022a0efadd99bcc58f7f1cc2b6fb3b808c40
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024123036-grout-exposure-3af8@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 9a45022a0efadd99bcc58f7f1cc2b6fb3b808c40 Mon Sep 17 00:00:00 2001
From: Filipe Manana <[email protected]>
Date: Mon, 9 Dec 2024 16:31:41 +0000
Subject: [PATCH] btrfs: allow swap activation to be interruptible

During swap activation we iterate over the extents of a file, then do several checks for each extent, some of which may take some significant time such as checking if an extent is shared. Since a file can have many thousands of extents, this can be a very slow operation and it's currently not interruptible. I had a bug during development of a previous patch that resulted in an infinite loop when iterating the extents, so a core was busy looping and I couldn't cancel the operation, which is very annoying and requires a reboot. So make the loop interruptible by checking for fatal signals at the end of each iteration and stopping immediately if there is one.

index b87f19630b00..c4675f4345fd 100644
@@ -10073,6 +10073,11 @@ static int btrfs_swap_activate(struct swap_info_struct *sis, struct file *file,
 			bsi.block_start = physical_block_start;
 			bsi.block_len = len;
 		}
+
+		if (fatal_signal_pending(current)) {
+			ret = -EINTR;
+			goto out;
+		}
 	}
 
 	if (bsi.block_len)