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 <ryan.roberts@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 55faf2effa46c690bdba691a39a0aca53e74eaca..dbf118b4060110ce3dc7ba50eb5b8e4b1e596387 100644 (file)
--- 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 7f8d1e11dbee24be7482fcd19f6eb51c75e5e49e..3b3efadb8cae8e067513b6e3bd7b1e8d79ed2d32 100644 (file)
--- 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 b67feb74b5da7274fb3ed744b63c73096e2f024e..52039fae1594c18dc616267ccaeace789e4775e2 100644 (file)
--- 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 c2181439f9258857e75cea1ca0791a2a353535fa..22999a402e029255e19026b7f42a0b864c213175 100644 (file)
--- 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 9e0625167517450d87172b2217f6981037f7a91d..854379021a040a4978e69305068c5b886c3fb0c4 100644 (file)
--- 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 d9b7ef1223437d4412e5a9b961f6481344f92576..2d3425cfa94b423926584de27f9e34c01cfaca02 100644 (file)
--- 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 b11f5b20b78b83dd44b1b3b667f7fdda0cf5f334..c3ed1c5117b23c856541cd5a9e409d6989e3899d 100644 (file)
--- 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 a74582aed7473af77bb72d76ca04c06f48159c2a..0e1d73955fa511c8b2167b3a24b4a1c24717fb91 100644 (file)
--- 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 2e99dffddfc5cce848c2929753e266a58de5c37f..55984007eabfb15848abd1680cbd2eb7899df1b5 100644 (file)
--- 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 1074ac4459f2ca78e353755b1f635d28211c8110..872dc0e41c6570722e5d87613c979087085e265a 100644 (file)
--- 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 2a9456a3e73049aad1d9f84efde4a8aef6914aca..aa810b535cfb127624e76219000764d54928feda 100644 (file)
--- 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 1d1b74950332e6b4ca829f6f5c9fe29fd993b260..7e4869017e54cfee849c42bb9143825fe518b936 100644 (file)
--- 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 5fd3b80fda1d5151c230321cb3228e935e4fa84b..644f02071a41b1ea24e69cf2ea4079dabc7267b7 100644 (file)
--- 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 63092cc0b1419d349feae89259a980dafab36c69..b50ce7dbc84a0ef2b428866a3fc70549dae07244 100644 (file)
--- 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