From 869176a096068056b338b5cc1b0af93106007f5d Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Mon, 6 Feb 2023 16:40:15 +0800 Subject: [PATCH] mm/vmalloc.c: add flags to mark vm_map_ram area Through vmalloc API, a virtual kernel area is reserved for physical address mapping. And vmap_area is used to track them, while vm_struct is allocated to associate with the vmap_area to store more information and passed out. However, area reserved via vm_map_ram() is an exception. It doesn't have vm_struct to associate with vmap_area. And we can't recognize the vmap_area with '->vm == NULL' as a vm_map_ram() area because the normal freeing path will set va->vm = NULL before unmapping, please see function remove_vm_area(). Meanwhile, there are two kinds of handling for vm_map_ram area. One is the whole vmap_area being reserved and mapped at one time through vm_map_area() interface; the other is the whole vmap_area with VMAP_BLOCK_SIZE size being reserved, while mapped into split regions with smaller size via vb_alloc(). To mark the area reserved through vm_map_ram(), add flags field into struct vmap_area. Bit 0 indicates this is vm_map_ram area created through vm_map_ram() interface, while bit 1 marks out the type of vm_map_ram area which makes use of vmap_block to manage split regions via vb_alloc/free(). This is a preparation for later use. Link: https://lkml.kernel.org/r/20230206084020.174506-3-bhe@redhat.com Signed-off-by: Baoquan He Reviewed-by: Lorenzo Stoakes Reviewed-by: Uladzislau Rezki (Sony) Cc: Dan Carpenter Cc: Stephen Brennan Signed-off-by: Andrew Morton --- include/linux/vmalloc.h | 1 + mm/vmalloc.c | 16 ++++++++++++---- 2 files changed, 13 insertions(+), 4 deletions(-) diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 096d48a..69250ef 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -76,6 +76,7 @@ struct vmap_area { unsigned long subtree_max_size; /* in "free" tree */ struct vm_struct *vm; /* in "busy" tree */ }; + unsigned long flags; /* mark type of vm_map_ram area */ }; /* archs that select HAVE_ARCH_HUGE_VMAP should override one or more of these */ diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 0f1396d..2d09601 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1578,7 +1578,8 @@ preload_this_cpu_lock(spinlock_t *lock, gfp_t gfp_mask, int node) static struct vmap_area *alloc_vmap_area(unsigned long size, unsigned long align, unsigned long vstart, unsigned long vend, - int node, gfp_t gfp_mask) + int node, gfp_t gfp_mask, + unsigned long va_flags) { struct vmap_area *va; unsigned long freed; @@ -1623,6 +1624,7 @@ retry: va->va_start = addr; va->va_end = addr + size; va->vm = NULL; + va->flags = va_flags; spin_lock(&vmap_area_lock); insert_vmap_area(va, &vmap_area_root, &vmap_area_list); @@ -1901,6 +1903,10 @@ static struct vmap_area *find_unlink_vmap_area(unsigned long addr) #define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE) +#define VMAP_RAM 0x1 /* indicates vm_map_ram area*/ +#define VMAP_BLOCK 0x2 /* mark out the vmap_block sub-type*/ +#define VMAP_FLAGS_MASK 0x3 + struct vmap_block_queue { spinlock_t lock; struct list_head free; @@ -1976,7 +1982,8 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask) va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE, VMALLOC_START, VMALLOC_END, - node, gfp_mask); + node, gfp_mask, + VMAP_RAM|VMAP_BLOCK); if (IS_ERR(va)) { kfree(vb); return ERR_CAST(va); @@ -2285,7 +2292,8 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node) } else { struct vmap_area *va; va = alloc_vmap_area(size, PAGE_SIZE, - VMALLOC_START, VMALLOC_END, node, GFP_KERNEL); + VMALLOC_START, VMALLOC_END, + node, GFP_KERNEL, VMAP_RAM); if (IS_ERR(va)) return NULL; @@ -2483,7 +2491,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size, if (!(flags & VM_NO_GUARD)) size += PAGE_SIZE; - va = alloc_vmap_area(size, align, start, end, node, gfp_mask); + va = alloc_vmap_area(size, align, start, end, node, gfp_mask, 0); if (IS_ERR(va)) { kfree(area); return NULL; -- 2.7.4