Commit 6ac433f8 authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Andrew Morton
Browse files

mm: rename cpu_bitmap field to flexible_array 

The cpu_bitmap flexible array now contains more than just the cpu_bitmap. 
In preparation for changing the static mm_struct definitions to cover for
the additional space required, change the cpu_bitmap type from "unsigned
long" to "char", require an unsigned long alignment of the flexible array,
and rename the field from "cpu_bitmap" to "flexible_array".

Introduce the MM_STRUCT_FLEXIBLE_ARRAY_INIT macro to statically initialize
the flexible array.  This covers the init_mm and efi_mm static
definitions.

This is a preparation step for fixing the missing mm_cid size for static
mm_struct definitions.

Link: https://lkml.kernel.org/r/20251224173358.647691-3-mathieu.desnoyers@efficios.com


Fixes: af7f588d ("sched: Introduce per-memory-map concurrency ID")
Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: default avatarThomas Gleixner <tglx@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Aboorva Devarajan <aboorvad@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Liam R . Howlett" <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Martin Liu <liumartin@google.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 12a6ddfc

drivers/firmware/efi/efi.c

+1 −1
Original line number Diff line number Diff line
@@ -74,10 +74,10 @@ struct mm_struct efi_mm = { 
	.page_table_lock	= __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),

	.mmlist			= LIST_HEAD_INIT(efi_mm.mmlist),

	.user_ns		= &init_user_ns,

	.cpu_bitmap		= { [BITS_TO_LONGS(NR_CPUS)] = 0},

#ifdef CONFIG_SCHED_MM_CID

	.mm_cid.lock		= __RAW_SPIN_LOCK_UNLOCKED(efi_mm.mm_cid.lock),

#endif

	.flexible_array		= MM_STRUCT_FLEXIBLE_ARRAY_INIT,

};



struct workqueue_struct *efi_rts_wq;

include/linux/mm_types.h

+9 −4
Original line number Diff line number Diff line
@@ -1329,7 +1329,7 @@ struct mm_struct { 
	 * The mm_cpumask needs to be at the end of mm_struct, because it

	 * is dynamically sized based on nr_cpu_ids.

	 */

	unsigned long cpu_bitmap[];

	char flexible_array[] __aligned(__alignof__(unsigned long));

};



/* Copy value to the first system word of mm flags, non-atomically. */
@@ -1366,19 +1366,24 @@ static inline void __mm_flags_set_mask_bits_word(struct mm_struct *mm, 
			 MT_FLAGS_USE_RCU)

extern struct mm_struct init_mm;



#define MM_STRUCT_FLEXIBLE_ARRAY_INIT				\

{								\

	[0 ... sizeof(cpumask_t)-1] = 0				\

}



/* Pointer magic because the dynamic array size confuses some compilers. */

static inline void mm_init_cpumask(struct mm_struct *mm)

{

	unsigned long cpu_bitmap = (unsigned long)mm;



	cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap);

	cpu_bitmap += offsetof(struct mm_struct, flexible_array);

	cpumask_clear((struct cpumask *)cpu_bitmap);

}



/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */

static inline cpumask_t *mm_cpumask(struct mm_struct *mm)

{

	return (struct cpumask *)&mm->cpu_bitmap;

	return (struct cpumask *)&mm->flexible_array;

}



#ifdef CONFIG_LRU_GEN
@@ -1469,7 +1474,7 @@ static inline cpumask_t *mm_cpus_allowed(struct mm_struct *mm) 
{

	unsigned long bitmap = (unsigned long)mm;



	bitmap += offsetof(struct mm_struct, cpu_bitmap);

	bitmap += offsetof(struct mm_struct, flexible_array);

	/* Skip cpu_bitmap */

	bitmap += cpumask_size();

	return (struct cpumask *)bitmap;

mm/init-mm.c

+1 −1
Original line number Diff line number Diff line
@@ -47,7 +47,7 @@ struct mm_struct init_mm = { 
#ifdef CONFIG_SCHED_MM_CID

	.mm_cid.lock = __RAW_SPIN_LOCK_UNLOCKED(init_mm.mm_cid.lock),

#endif

	.cpu_bitmap	= CPU_BITS_NONE,

	.flexible_array	= MM_STRUCT_FLEXIBLE_ARRAY_INIT,

	INIT_MM_CONTEXT(init_mm)

};