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Commit 66f0dc48 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

mm: move sys_mmap_pgoff from util.c 



Move sys_mmap_pgoff() from mm/util.c to mm/mmap.c and mm/nommu.c,
where we'd expect to find such code: especially now that it contains
the MAP_HUGETLB handling.  Revert mm/util.c to how it was in 2.6.32.

This patch just ignores MAP_HUGETLB in the nommu case, as in 2.6.32,
whereas 2.6.33-rc2 reported -ENOSYS.  Perhaps validate_mmap_request()
should reject it with -EINVAL?  Add that later if necessary.

Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 75c85a0b

mm/mmap.c

+40 −0
Original line number Diff line number Diff line
@@ -1043,6 +1043,46 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, 
}

EXPORT_SYMBOL(do_mmap_pgoff);



SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,

		unsigned long, prot, unsigned long, flags,

		unsigned long, fd, unsigned long, pgoff)

{

	struct file *file = NULL;

	unsigned long retval = -EBADF;



	if (!(flags & MAP_ANONYMOUS)) {

		if (unlikely(flags & MAP_HUGETLB))

			return -EINVAL;

		file = fget(fd);

		if (!file)

			goto out;

	} else if (flags & MAP_HUGETLB) {

		struct user_struct *user = NULL;

		/*

		 * VM_NORESERVE is used because the reservations will be

		 * taken when vm_ops->mmap() is called

		 * A dummy user value is used because we are not locking

		 * memory so no accounting is necessary

		 */

		len = ALIGN(len, huge_page_size(&default_hstate));

		file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE,

						&user, HUGETLB_ANONHUGE_INODE);

		if (IS_ERR(file))

			return PTR_ERR(file);

	}



	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);



	down_write(&current->mm->mmap_sem);

	retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);

	up_write(&current->mm->mmap_sem);



	if (file)

		fput(file);

out:

	return retval;

}



/*

 * Some shared mappigns will want the pages marked read-only

 * to track write events. If so, we'll downgrade vm_page_prot

mm/nommu.c

+25 −0
Original line number Diff line number Diff line
@@ -1398,6 +1398,31 @@ unsigned long do_mmap_pgoff(struct file *file, 
}

EXPORT_SYMBOL(do_mmap_pgoff);



SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,

		unsigned long, prot, unsigned long, flags,

		unsigned long, fd, unsigned long, pgoff)

{

	struct file *file = NULL;

	unsigned long retval = -EBADF;



	if (!(flags & MAP_ANONYMOUS)) {

		file = fget(fd);

		if (!file)

			goto out;

	}



	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);



	down_write(&current->mm->mmap_sem);

	retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);

	up_write(&current->mm->mmap_sem);



	if (file)

		fput(file);

out:

	return retval;

}



/*

 * split a vma into two pieces at address 'addr', a new vma is allocated either

 * for the first part or the tail.

mm/util.c

+0 −44
Original line number Diff line number Diff line
@@ -4,10 +4,6 @@ 
#include <linux/module.h>

#include <linux/err.h>

#include <linux/sched.h>

#include <linux/hugetlb.h>

#include <linux/syscalls.h>

#include <linux/mman.h>

#include <linux/file.h>

#include <asm/uaccess.h>



#define CREATE_TRACE_POINTS
@@ -272,46 +268,6 @@ int __attribute__((weak)) get_user_pages_fast(unsigned long start, 
}

EXPORT_SYMBOL_GPL(get_user_pages_fast);



SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,

		unsigned long, prot, unsigned long, flags,

		unsigned long, fd, unsigned long, pgoff)

{

	struct file * file = NULL;

	unsigned long retval = -EBADF;



	if (!(flags & MAP_ANONYMOUS)) {

		if (unlikely(flags & MAP_HUGETLB))

			return -EINVAL;

		file = fget(fd);

		if (!file)

			goto out;

	} else if (flags & MAP_HUGETLB) {

		struct user_struct *user = NULL;

		/*

		 * VM_NORESERVE is used because the reservations will be

		 * taken when vm_ops->mmap() is called

		 * A dummy user value is used because we are not locking

		 * memory so no accounting is necessary

		 */

		len = ALIGN(len, huge_page_size(&default_hstate));

		file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE,

						&user, HUGETLB_ANONHUGE_INODE);

		if (IS_ERR(file))

			return PTR_ERR(file);

	}



	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);



	down_write(&current->mm->mmap_sem);

	retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);

	up_write(&current->mm->mmap_sem);



	if (file)

		fput(file);

out:

	return retval;

}



/* Tracepoints definitions. */

EXPORT_TRACEPOINT_SYMBOL(kmalloc);

EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);