From 2a1eb111d2859b13e5ff87baa6cfe343317b07bf Mon Sep 17 00:00:00 2001 From: Uros Bizjak Date: Fri, 30 Aug 2024 11:10:50 +0200 Subject: [PATCH] squashfs: fix percpu address space issues in decompressor_multi_percpu.c 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@gmail.com Signed-off-by: Uros Bizjak Cc: Phillip Lougher Signed-off-by: Andrew Morton --- fs/squashfs/decompressor_multi_percpu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/squashfs/decompressor_multi_percpu.c b/fs/squashfs/decompressor_multi_percpu.c index 8a218e7c2390f..e4d7e507b2688 100644 --- a/fs/squashfs/decompressor_multi_percpu.c +++ b/fs/squashfs/decompressor_multi_percpu.c @@ -46,7 +46,7 @@ static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk, } 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 squashfs_sb_info *msblk, struct bio *bio, { 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); -- 2.39.5