[PATCH] mm: Remove mm argument from mm_get_unmapped_area()

From: Rick Edgecombe
Date: Mon May 06 2024 - 12:08:15 EST

Recently the get_unmapped_area() pointer on mm_struct was removed in
favor of direct callable function that can determines which of two
handlers to call based on an mm flag. This function,
mm_get_unmapped_area(), checks the flag of the mm passed as an argument.

Dan Williams pointed out (see link) that all callers pass curret->mm, so
the mm argument is unneeded. It could be conceivable for a caller to want
to pass a different mm in the future, but in this case a new helper could
easily be added.

So remove the mm argument, and rename the function
current_get_unmapped_area().

Fixes: 529ce23a764f ("mm: switch mm->get_unmapped_area() to a flag")
Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
Link: https://lore.kernel.org/lkml/6603bed6662a_4a98a2949e@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.notmuch/
---
Based on linux-next.
---
arch/sparc/kernel/sys_sparc_64.c | 9 +++++----
arch/x86/kernel/cpu/sgx/driver.c | 2 +-
drivers/char/mem.c | 2 +-
drivers/dax/device.c | 6 +++---
fs/proc/inode.c | 2 +-
fs/ramfs/file-mmu.c | 2 +-
include/linux/sched/mm.h | 6 +++---
io_uring/memmap.c | 2 +-
kernel/bpf/arena.c | 2 +-
kernel/bpf/syscall.c | 2 +-
mm/mmap.c | 11 +++++------
mm/shmem.c | 9 ++++-----
12 files changed, 27 insertions(+), 28 deletions(-)

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index d9c3b34ca744..cf0b4ace5bf9 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -220,7 +220,7 @@ 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 current_get_unmapped_area(NULL, orig_addr, len, pgoff, flags);
}
flags &= ~MAP_SHARED;

@@ -233,8 +233,9 @@ 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,
- len + (align_goal - PAGE_SIZE), pgoff, flags);
+ addr = current_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);
break;
@@ -252,7 +253,7 @@ 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 = current_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 22b65a5f5ec6..5f7bfd9035f7 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 current_get_unmapped_area(file, addr, len, pgoff, flags);
}

#ifdef CONFIG_COMPAT
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 7c359cc406d5..a29c4bd506d5 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -546,7 +546,7 @@ static unsigned long get_unmapped_area_zero(struct file *file,
}

/* Otherwise flags & MAP_PRIVATE: with no shmem object beneath it */
- return mm_get_unmapped_area(current->mm, file, addr, len, pgoff, flags);
+ return current_get_unmapped_area(file, addr, len, pgoff, flags);
#else
return -ENOSYS;
#endif
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index eb61598247a9..c379902307b7 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -329,14 +329,14 @@ 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 = current_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 current_get_unmapped_area(filp, addr, len, pgoff, flags);
}

static const struct address_space_operations dev_dax_aops = {
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index d19434e2a58e..24a6aeac3de5 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -455,7 +455,7 @@ 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 current_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 b45c7edc3225..85f57de31102 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 current_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 91546493c43d..c67c7de05c7a 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -187,9 +187,9 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags);

-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 current_get_unmapped_area(struct file *filp, unsigned long addr,
+ unsigned long len, unsigned long pgoff,
+ unsigned long flags);

unsigned long
arch_get_unmapped_area_vmflags(struct file *filp, unsigned long addr,
diff --git a/io_uring/memmap.c b/io_uring/memmap.c
index 4785d6af5fee..1aaea32c797c 100644
--- a/io_uring/memmap.c
+++ b/io_uring/memmap.c
@@ -305,7 +305,7 @@ 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 current_get_unmapped_area(filp, addr, len, pgoff, flags);
}

#else /* !CONFIG_MMU */
diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c
index 4a1be699bb82..054486f7c453 100644
--- a/kernel/bpf/arena.c
+++ b/kernel/bpf/arena.c
@@ -314,7 +314,7 @@ 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 = current_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 2222c3ff88e7..d9ff2843f6ef 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -992,7 +992,7 @@ 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 current_get_unmapped_area(filp, addr, len, pgoff, flags);
#else
return addr;
#endif
diff --git a/mm/mmap.c b/mm/mmap.c
index 83b4682ec85c..4e98a907c53d 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1901,16 +1901,15 @@ __get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
return error ? error : addr;
}

-unsigned long
-mm_get_unmapped_area(struct mm_struct *mm, struct file *file,
- unsigned long addr, unsigned long len,
- unsigned long pgoff, unsigned long flags)
+unsigned long current_get_unmapped_area(struct file *file, unsigned long addr,
+ unsigned long len, unsigned long pgoff,
+ unsigned long flags)
{
- if (test_bit(MMF_TOPDOWN, &mm->flags))
+ if (test_bit(MMF_TOPDOWN, &current->mm->flags))
return arch_get_unmapped_area_topdown(file, addr, len, pgoff, flags);
return arch_get_unmapped_area(file, addr, len, pgoff, flags);
}
-EXPORT_SYMBOL(mm_get_unmapped_area);
+EXPORT_SYMBOL(current_get_unmapped_area);

/**
* find_vma_intersection() - Look up the first VMA which intersects the interval
diff --git a/mm/shmem.c b/mm/shmem.c
index f5d60436b604..c0acd7db93c8 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2276,8 +2276,7 @@ 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 = current_get_unmapped_area(file, uaddr, len, pgoff, flags);

if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
return addr;
@@ -2334,8 +2333,8 @@ 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 = current_get_unmapped_area(NULL, uaddr,
+ inflated_len, 0, flags);
if (IS_ERR_VALUE(inflated_addr))
return addr;
if (inflated_addr & ~PAGE_MASK)
@@ -4799,7 +4798,7 @@ 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 current_get_unmapped_area(file, addr, len, pgoff, flags);
}
#endif


base-commit: 9221b2819b8a4196eecf5476d66201be60fbcf29
--
2.34.1