+ iov_iter-iov_folioq_get_pages-dont-leave-empty-slot-behind.patch added to mm-nonmm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: iov_iter: iov_folioq_get_pages: don't leave empty slot behind
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     iov_iter-iov_folioq_get_pages-dont-leave-empty-slot-behind.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/iov_iter-iov_folioq_get_pages-dont-leave-empty-slot-behind.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Dominique Martinet <asmadeus@codewreck.org>
Subject: iov_iter: iov_folioq_get_pages: don't leave empty slot behind
Date: Mon, 11 Aug 2025 16:39:06 +0900

After advancing into a folioq it makes more sense to point to the next
slot than at the end of the current slot.  This should not be needed for
correctness, but this also happens to "fix" the 9p bug with
iterate_folioq() not copying properly.

Link: https://lkml.kernel.org/r/20250811-iot_iter_folio-v1-2-d9c223adf93c@codewreck.org
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnout Engelen <arnout@bzzt.net>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Theune <ct@flyingcircus.io>
Cc: David Howells <dhowells@redhat.com>
Cc: Maximilian Bosch <maximilian@mbosch.me>
Cc: Ryan Lahfa <ryan@lahfa.xyz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/iov_iter.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/lib/iov_iter.c~iov_iter-iov_folioq_get_pages-dont-leave-empty-slot-behind
+++ a/lib/iov_iter.c
@@ -1032,9 +1032,6 @@ static ssize_t iter_folioq_get_pages(str
 			maxpages--;
 		}
 
-		if (maxpages == 0 || extracted >= maxsize)
-			break;
-
 		if (iov_offset >= fsize) {
 			iov_offset = 0;
 			slot++;
@@ -1043,6 +1040,9 @@ static ssize_t iter_folioq_get_pages(str
 				slot = 0;
 			}
 		}
+
+		if (maxpages == 0 || extracted >= maxsize)
+			break;
 	}
 
 	iter->count = count;
_

Patches currently in -mm which might be from asmadeus@codewreck.org are

iov_iter-iterate_folioq-fix-handling-of-offset-=-folio-size.patch
iov_iter-iov_folioq_get_pages-dont-leave-empty-slot-behind.patch