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From: Hugh Dickins on 30 Dec 2009 15:20
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: Hugh Dickins <hugh.dickins(a)tiscali.co.uk>
---

mm/mmap.c | 40 ++++++++++++++++++++++++++++++++++++++++
mm/nommu.c | 25 +++++++++++++++++++++++++
mm/util.c | 44 --------------------------------------------
3 files changed, 65 insertions(+), 44 deletions(-)

--- 2.6.33-rc2/mm/mmap.c 2009-12-18 11:42:54.000000000 +0000
+++ linux/mm/mmap.c 2009-12-26 18:28:30.000000000 +0000
@@ -1043,6 +1043,46 @@ unsigned long do_mmap_pgoff(struct 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)) {
+ 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
--- 2.6.33-rc2/mm/nommu.c 2009-12-18 11:42:54.000000000 +0000
+++ linux/mm/nommu.c 2009-12-26 18:28:30.000000000 +0000
@@ -1398,6 +1398,31 @@ error_getting_region:
}
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.
--- 2.6.33-rc2/mm/util.c 2009-12-18 11:42:55.000000000 +0000
+++ linux/mm/util.c 2009-12-26 18:28:30.000000000 +0000
@@ -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
}
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);
--
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Prev: BCM70010 (crystalhd) Linux Driver
Next: [PATCH 4/5] reiserfs: Safely acquire i_mutex from reiserfs_for_each_xattr