* [PATCH] dcache: use kmalloc_flex() in __d_alloc
@ 2026-04-17 9:42 Thorsten Blum
2026-04-17 12:00 ` Jori Koolstra
0 siblings, 1 reply; 2+ messages in thread
From: Thorsten Blum @ 2026-04-17 9:42 UTC (permalink / raw)
To: Alexander Viro, Christian Brauner, Jan Kara
Cc: Thorsten Blum, linux-fsdevel, linux-kernel
Use kmalloc_flex() when allocating a new 'struct external_name' in
__d_alloc() to replace offsetof() and the open-coded size arithmetic,
and to keep the size type-safe.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
fs/dcache.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index dbcbd0affb26..4568f9530166 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1753,10 +1753,10 @@ static struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
name = &slash_name;
dname = dentry->d_shortname.string;
} else if (name->len > DNAME_INLINE_LEN-1) {
- size_t size = offsetof(struct external_name, name[1]);
- struct external_name *p = kmalloc(size + name->len,
- GFP_KERNEL_ACCOUNT |
- __GFP_RECLAIMABLE);
+ struct external_name *p;
+
+ p = kmalloc_flex(*p, name, name->len + 1,
+ GFP_KERNEL_ACCOUNT | __GFP_RECLAIMABLE);
if (!p) {
kmem_cache_free(dentry_cache, dentry);
return NULL;
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] dcache: use kmalloc_flex() in __d_alloc
2026-04-17 9:42 [PATCH] dcache: use kmalloc_flex() in __d_alloc Thorsten Blum
@ 2026-04-17 12:00 ` Jori Koolstra
0 siblings, 0 replies; 2+ messages in thread
From: Jori Koolstra @ 2026-04-17 12:00 UTC (permalink / raw)
To: Thorsten Blum
Cc: Alexander Viro, Christian Brauner, Jan Kara, linux-fsdevel,
linux-kernel
On Fri, Apr 17, 2026 at 11:42:40AM +0200, Thorsten Blum wrote:
> Use kmalloc_flex() when allocating a new 'struct external_name' in
> __d_alloc() to replace offsetof() and the open-coded size arithmetic,
> and to keep the size type-safe.
>
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
> fs/dcache.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/dcache.c b/fs/dcache.c
> index dbcbd0affb26..4568f9530166 100644
> --- a/fs/dcache.c
> +++ b/fs/dcache.c
> @@ -1753,10 +1753,10 @@ static struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
> name = &slash_name;
> dname = dentry->d_shortname.string;
> } else if (name->len > DNAME_INLINE_LEN-1) {
> - size_t size = offsetof(struct external_name, name[1]);
> - struct external_name *p = kmalloc(size + name->len,
> - GFP_KERNEL_ACCOUNT |
> - __GFP_RECLAIMABLE);
> + struct external_name *p;
> +
> + p = kmalloc_flex(*p, name, name->len + 1,
> + GFP_KERNEL_ACCOUNT | __GFP_RECLAIMABLE);
> if (!p) {
> kmem_cache_free(dentry_cache, dentry);
> return NULL;
Looks reasonable to me. Is the idea to completely outphase this old way
of requesting memory for structs with flexible array members?
Feel free to add:
Reviewed-by: Jori Koolstra <jkoolstra@xs4all.nl>
^ permalink raw reply [flat|nested] 2+ messages in thread
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