From: Ryan Roberts Date: Fri, 3 Oct 2025 15:53:04 +0000 (+0100) Subject: mm: consistently use current->mm in mm_get_unmapped_area() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=962ea6f639957d2a397a30fa30199633e08d7364;p=users%2Fjedix%2Flinux-maple.git mm: consistently use current->mm in mm_get_unmapped_area() mm_get_unmapped_area() is a wrapper around arch_get_unmapped_area() / arch_get_unmapped_area_topdown(), both of which search current->mm for some free space. Neither take an mm_struct - they implicitly operate on current->mm. But the wrapper takes an mm_struct and uses it to decide whether to search bottom up or top down. All callers pass in current->mm for this, so everything is working consistently. But it feels like an accident waiting to happen; eventually someone will call that function with a different mm, expecting to find free space in it, but what gets returned is free space in the current mm. So let's simplify by removing the parameter and have the wrapper use current->mm to decide which end to start at. Now everything is consistent and self-documenting. Link: https://lkml.kernel.org/r/20251003155306.2147572-1-ryan.roberts@arm.com Signed-off-by: Ryan Roberts Acked-by: David Hildenbrand Reviewed-by: Oscar Salvador Reviewed-by: Dev Jain Reviewed-by: Anshuman Khandual Reviewed-by: Lorenzo Stoakes Reviewed-by: Baolin Wang Cc: Liam Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c index 55faf2effa46..dbf118b40601 100644 --- a/arch/sparc/kernel/sys_sparc_64.c +++ b/arch/sparc/kernel/sys_sparc_64.c @@ -241,7 +241,7 @@ unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr, u if (flags & MAP_FIXED) { /* Ok, don't mess with it. */ - return mm_get_unmapped_area(current->mm, NULL, orig_addr, len, pgoff, flags); + return mm_get_unmapped_area(NULL, orig_addr, len, pgoff, flags); } flags &= ~MAP_SHARED; @@ -254,7 +254,7 @@ unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr, u align_goal = (64UL * 1024); do { - addr = mm_get_unmapped_area(current->mm, NULL, orig_addr, + addr = mm_get_unmapped_area(NULL, orig_addr, len + (align_goal - PAGE_SIZE), pgoff, flags); if (!(addr & ~PAGE_MASK)) { addr = (addr + (align_goal - 1UL)) & ~(align_goal - 1UL); @@ -273,7 +273,7 @@ unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr, u * be obtained. */ if (addr & ~PAGE_MASK) - addr = mm_get_unmapped_area(current->mm, NULL, orig_addr, len, pgoff, flags); + addr = mm_get_unmapped_area(NULL, orig_addr, len, pgoff, flags); return addr; } diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c index 7f8d1e11dbee..3b3efadb8cae 100644 --- a/arch/x86/kernel/cpu/sgx/driver.c +++ b/arch/x86/kernel/cpu/sgx/driver.c @@ -113,7 +113,7 @@ static unsigned long sgx_get_unmapped_area(struct file *file, if (flags & MAP_FIXED) return addr; - return mm_get_unmapped_area(current->mm, file, addr, len, pgoff, flags); + return mm_get_unmapped_area(file, addr, len, pgoff, flags); } #ifdef CONFIG_COMPAT diff --git a/drivers/char/mem.c b/drivers/char/mem.c index b67feb74b5da..52039fae1594 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -558,7 +558,7 @@ static unsigned long get_unmapped_area_zero(struct file *file, #ifdef CONFIG_TRANSPARENT_HUGEPAGE return thp_get_unmapped_area(file, addr, len, pgoff, flags); #else - return mm_get_unmapped_area(current->mm, file, addr, len, pgoff, flags); + return mm_get_unmapped_area(file, addr, len, pgoff, flags); #endif } #endif /* CONFIG_MMU */ diff --git a/drivers/dax/device.c b/drivers/dax/device.c index c2181439f925..22999a402e02 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -340,14 +340,13 @@ static unsigned long dax_get_unmapped_area(struct file *filp, if ((off + len_align) < off) goto out; - addr_align = mm_get_unmapped_area(current->mm, filp, addr, len_align, - pgoff, flags); + addr_align = mm_get_unmapped_area(filp, addr, len_align, pgoff, flags); if (!IS_ERR_VALUE(addr_align)) { addr_align += (off - addr_align) & (align - 1); return addr_align; } out: - return mm_get_unmapped_area(current->mm, filp, addr, len, pgoff, flags); + return mm_get_unmapped_area(filp, addr, len, pgoff, flags); } static const struct address_space_operations dev_dax_aops = { diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 9e0625167517..854379021a04 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -194,8 +194,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr, if (addr) addr0 = ALIGN(addr, huge_page_size(h)); - return mm_get_unmapped_area_vmflags(current->mm, file, addr0, len, pgoff, - flags, 0); + return mm_get_unmapped_area_vmflags(file, addr0, len, pgoff, flags, 0); } /* diff --git a/fs/proc/inode.c b/fs/proc/inode.c index d9b7ef122343..2d3425cfa94b 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -443,7 +443,7 @@ pde_get_unmapped_area(struct proc_dir_entry *pde, struct file *file, unsigned lo return pde->proc_ops->proc_get_unmapped_area(file, orig_addr, len, pgoff, flags); #ifdef CONFIG_MMU - return mm_get_unmapped_area(current->mm, file, orig_addr, len, pgoff, flags); + return mm_get_unmapped_area(file, orig_addr, len, pgoff, flags); #endif return orig_addr; diff --git a/fs/ramfs/file-mmu.c b/fs/ramfs/file-mmu.c index b11f5b20b78b..c3ed1c5117b2 100644 --- a/fs/ramfs/file-mmu.c +++ b/fs/ramfs/file-mmu.c @@ -35,7 +35,7 @@ static unsigned long ramfs_mmu_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { - return mm_get_unmapped_area(current->mm, file, addr, len, pgoff, flags); + return mm_get_unmapped_area(file, addr, len, pgoff, flags); } const struct file_operations ramfs_file_operations = { diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index a74582aed747..0e1d73955fa5 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -189,12 +189,11 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags, vm_flags_t); -unsigned long mm_get_unmapped_area(struct mm_struct *mm, struct file *filp, - unsigned long addr, unsigned long len, - unsigned long pgoff, unsigned long flags); +unsigned long mm_get_unmapped_area(struct file *filp, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags); -unsigned long mm_get_unmapped_area_vmflags(struct mm_struct *mm, - struct file *filp, +unsigned long mm_get_unmapped_area_vmflags(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, diff --git a/io_uring/memmap.c b/io_uring/memmap.c index 2e99dffddfc5..55984007eabf 100644 --- a/io_uring/memmap.c +++ b/io_uring/memmap.c @@ -387,7 +387,7 @@ unsigned long io_uring_get_unmapped_area(struct file *filp, unsigned long addr, #else addr = 0UL; #endif - return mm_get_unmapped_area(current->mm, filp, addr, len, pgoff, flags); + return mm_get_unmapped_area(filp, addr, len, pgoff, flags); } #else /* !CONFIG_MMU */ diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c index 1074ac4459f2..872dc0e41c65 100644 --- a/kernel/bpf/arena.c +++ b/kernel/bpf/arena.c @@ -334,7 +334,7 @@ static unsigned long arena_get_unmapped_area(struct file *filp, unsigned long ad return -EINVAL; } - ret = mm_get_unmapped_area(current->mm, filp, addr, len * 2, 0, flags); + ret = mm_get_unmapped_area(filp, addr, len * 2, 0, flags); if (IS_ERR_VALUE(ret)) return ret; if ((ret >> 32) == ((ret + len - 1) >> 32)) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 2a9456a3e730..aa810b535cfb 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1147,7 +1147,7 @@ static unsigned long bpf_get_unmapped_area(struct file *filp, unsigned long addr if (map->ops->map_get_unmapped_area) return map->ops->map_get_unmapped_area(filp, addr, len, pgoff, flags); #ifdef CONFIG_MMU - return mm_get_unmapped_area(current->mm, filp, addr, len, pgoff, flags); + return mm_get_unmapped_area(filp, addr, len, pgoff, flags); #else return addr; #endif diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1d1b74950332..7e4869017e54 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1126,7 +1126,7 @@ static unsigned long __thp_get_unmapped_area(struct file *filp, if (len_pad < len || (off + len_pad) < off) return 0; - ret = mm_get_unmapped_area_vmflags(current->mm, filp, addr, len_pad, + ret = mm_get_unmapped_area_vmflags(filp, addr, len_pad, off >> PAGE_SHIFT, flags, vm_flags); /* @@ -1163,7 +1163,7 @@ unsigned long thp_get_unmapped_area_vmflags(struct file *filp, unsigned long add if (ret) return ret; - return mm_get_unmapped_area_vmflags(current->mm, filp, addr, len, pgoff, flags, + return mm_get_unmapped_area_vmflags(filp, addr, len, pgoff, flags, vm_flags); } diff --git a/mm/mmap.c b/mm/mmap.c index 5fd3b80fda1d..644f02071a41 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -797,12 +797,11 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, } #endif -unsigned long mm_get_unmapped_area_vmflags(struct mm_struct *mm, struct file *filp, - unsigned long addr, unsigned long len, - unsigned long pgoff, unsigned long flags, - vm_flags_t vm_flags) +unsigned long mm_get_unmapped_area_vmflags(struct file *filp, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags, vm_flags_t vm_flags) { - if (mm_flags_test(MMF_TOPDOWN, mm)) + if (mm_flags_test(MMF_TOPDOWN, current->mm)) return arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags, vm_flags); return arch_get_unmapped_area(filp, addr, len, pgoff, flags, vm_flags); @@ -848,7 +847,7 @@ __get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, addr = thp_get_unmapped_area_vmflags(file, addr, len, pgoff, flags, vm_flags); } else { - addr = mm_get_unmapped_area_vmflags(current->mm, file, addr, len, + addr = mm_get_unmapped_area_vmflags(file, addr, len, pgoff, flags, vm_flags); } if (IS_ERR_VALUE(addr)) @@ -864,12 +863,10 @@ __get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, } unsigned long -mm_get_unmapped_area(struct mm_struct *mm, struct file *file, - unsigned long addr, unsigned long len, +mm_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { - return mm_get_unmapped_area_vmflags(mm, file, addr, len, - pgoff, flags, 0); + return mm_get_unmapped_area_vmflags(file, addr, len, pgoff, flags, 0); } EXPORT_SYMBOL(mm_get_unmapped_area); diff --git a/mm/shmem.c b/mm/shmem.c index 63092cc0b141..b50ce7dbc84a 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2756,8 +2756,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, if (len > TASK_SIZE) return -ENOMEM; - addr = mm_get_unmapped_area(current->mm, file, uaddr, len, pgoff, - flags); + addr = mm_get_unmapped_area(file, uaddr, len, pgoff, flags); if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) return addr; @@ -2835,8 +2834,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, if (inflated_len < len) return addr; - inflated_addr = mm_get_unmapped_area(current->mm, NULL, uaddr, - inflated_len, 0, flags); + inflated_addr = mm_get_unmapped_area(NULL, uaddr, inflated_len, 0, flags); if (IS_ERR_VALUE(inflated_addr)) return addr; if (inflated_addr & ~PAGE_MASK) @@ -5773,7 +5771,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { - return mm_get_unmapped_area(current->mm, file, addr, len, pgoff, flags); + return mm_get_unmapped_area(file, addr, len, pgoff, flags); } #endif