[merged mm-nonmm-stable] squashfs-fix-percpu-address-space-issues-in-decompressor_multi_percpuc.patch removed from -mm tree

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The quilt patch titled
     Subject: squashfs: fix percpu address space issues in decompressor_multi_percpu.c
has been removed from the -mm tree.  Its filename was
     squashfs-fix-percpu-address-space-issues-in-decompressor_multi_percpuc.patch

This patch was dropped because it was merged into the mm-nonmm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Uros Bizjak <ubizjak@xxxxxxxxx>
Subject: squashfs: fix percpu address space issues in decompressor_multi_percpu.c
Date: Fri, 30 Aug 2024 11:10:50 +0200

When strict percpu address space checks are enabled, then current direct
casts between the percpu address space and the generic address space fail
the compilation on x86_64 with:

decompressor_multi_percpu.c: In function `squashfs_decompressor_create':
decompressor_multi_percpu.c:49:16: error: cast to generic address space pointer from disjoint `__seg_gs' address space pointer

decompressor_multi_percpu.c: In function `squashfs_decompressor_destroy':
decompressor_multi_percpu.c:64:25: error: cast to `__seg_gs' address space pointer from disjoint generic address space pointer

decompressor_multi_percpu.c: In function `squashfs_decompress':
decompressor_multi_percpu.c:82:25: error: cast to `__seg_gs' address space pointer from disjoint generic address space pointer

Add intermediate casts to unsigned long, as advised in [1] and [2].

Side note: sparse still requires __force when casting from the percpu
address space, although the documentation [2] allows casts to unsigned
long without __force attribute.

Found by GCC's named address space checks.

There were no changes in the resulting object file.

[1] https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html#x86-Named-Address-Spaces
[2] https://sparse.docs.kernel.org/en/latest/annotations.html#address-space-name

Link: https://lkml.kernel.org/r/20240830091104.13049-1-ubizjak@xxxxxxxxx
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Cc: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 fs/squashfs/decompressor_multi_percpu.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/fs/squashfs/decompressor_multi_percpu.c~squashfs-fix-percpu-address-space-issues-in-decompressor_multi_percpuc
+++ a/fs/squashfs/decompressor_multi_percpu.c
@@ -46,7 +46,7 @@ static void *squashfs_decompressor_creat
 	}
 
 	kfree(comp_opts);
-	return (__force void *) percpu;
+	return (void *)(__force unsigned long) percpu;
 
 out:
 	for_each_possible_cpu(cpu) {
@@ -61,7 +61,7 @@ out:
 static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
 {
 	struct squashfs_stream __percpu *percpu =
-			(struct squashfs_stream __percpu *) msblk->stream;
+			(void __percpu *)(unsigned long) msblk->stream;
 	struct squashfs_stream *stream;
 	int cpu;
 
@@ -79,7 +79,7 @@ static int squashfs_decompress(struct sq
 {
 	struct squashfs_stream *stream;
 	struct squashfs_stream __percpu *percpu =
-			(struct squashfs_stream __percpu *) msblk->stream;
+			(void __percpu *)(unsigned long) msblk->stream;
 	int res;
 
 	local_lock(&percpu->lock);
_

Patches currently in -mm which might be from ubizjak@xxxxxxxxx are






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