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dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ilg2EUFm; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf13.hostedemail.com: domain of bhe@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=bhe@redhat.com X-Rspamd-Server: rspam03 X-HE-Tag: 1667965010-879044 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Through vmalloc API, a virtual kernel area is reserved for physical address mapping. And vmap_area is used to track them, and 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 simply recognize the vm_map_ram areas with '->vm == NULL' because the normal freeing path will set va->vm = NULL before unmapping, please see function remove_vm_area(). Meanwhile, there are two types of vm_map_ram area. One is the whole vmap_area being reserved and mapped at one time; the other is the whole vmap_area with VMAP_BLOCK_SIZE size being reserved, while mapped into split regions with smaller size several times. To mark the area reserved through vm_map_ram(), add flags into the union field of struct vmap_area to reuse the space since that union space is free anyway if it's vm_map_ram area. This is a preparatoin for later use. Signed-off-by: Baoquan He --- include/linux/vmalloc.h | 1 + mm/vmalloc.c | 17 ++++++++++++++++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 096d48aa3437..b739a60b73da 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -75,6 +75,7 @@ struct vmap_area { union { 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 */ }; }; diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 5d3fd3e6fe09..41d82dc07e13 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1815,6 +1815,7 @@ static void free_vmap_area_noflush(struct vmap_area *va) spin_lock(&vmap_area_lock); unlink_va(va, &vmap_area_root); + va->flags = 0; spin_unlock(&vmap_area_lock); nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >> @@ -1887,6 +1888,9 @@ struct vmap_area *find_vmap_area(unsigned long addr) #define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE) +#define VMAP_RAM 0x1 +#define VMAP_BLOCK 0x2 + struct vmap_block_queue { spinlock_t lock; struct list_head free; @@ -1967,6 +1971,9 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask) kfree(vb); return ERR_CAST(va); } + spin_lock(&vmap_area_lock); + va->flags = VMAP_RAM|VMAP_BLOCK; + spin_unlock(&vmap_area_lock); vaddr = vmap_block_vaddr(va->va_start, 0); spin_lock_init(&vb->lock); @@ -2229,8 +2236,12 @@ void vm_unmap_ram(const void *mem, unsigned int count) return; } - va = find_vmap_area(addr); + spin_lock(&vmap_area_lock); + va = __find_vmap_area((unsigned long)addr, &vmap_area_root); BUG_ON(!va); + if (va) + va->flags &= ~VMAP_RAM; + spin_unlock(&vmap_area_lock); debug_check_no_locks_freed((void *)va->va_start, (va->va_end - va->va_start)); free_unmap_vmap_area(va); @@ -2269,6 +2280,10 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node) if (IS_ERR(va)) return NULL; + spin_lock(&vmap_area_lock); + va->flags = VMAP_RAM; + spin_unlock(&vmap_area_lock); + addr = va->va_start; mem = (void *)addr; }