untangle the do_mremap() mess

This backports the following upstream commits all as one patch:
	54f5de709984bae0d31d823ff03de755f9dcac54
	ecc1a8993751de4e82eb18640d631dae1f626bd6
	1a0ef85f84feb13f07b604fcf5b90ef7c2b5c82f
	f106af4e90eadd76cfc0b5325f659619e08fb762
	097eed103862f9c6a97f2e415e21d1134017b135
	935874141df839c706cd6cdc438e85eb69d1525e
	0ec62d290912bb4b989be7563851bc364ec73b56
	c4caa778157dbbf04116f0ac2111e389b5cd7a29
	2ea1d13f64efdf49319e86c87d9ba38c30902782
	570dcf2c15463842e384eb597a87c1e39bead99b
	564b3bffc619dcbdd160de597b0547a7017ea010
	0067bd8a55862ac9dd212bd1c4f6f5bff1ca1301
	f8b7256096a20436f6d0926747e3ac3d64c81d24
	8c7b49b3ecd48923eb64ff57e07a1cdb74782970
	9206de95b1ea68357996ec02be5db0638a0de2c1
	2c6a10161d0b5fc047b5bd81b03693b9af99fab5
	05d72faa6d13c9d857478a5d35c85db9adada685
	bb52d6694002b9d632bb355f64daa045c6293a4e
	e77414e0aad6a1b063ba5e5750c582c75327ea6a
	aa65607373a4daf2010e8c3867b6317619f3c1a3

Backport done by Greg Kroah-Hartman.  Only minor tweaks were needed.

Cc: David S. Miller <davem@davemloft.net>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 6 insertions, 45 deletions

diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index b77fefaff9da..ea4a74652cf8 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -67,28 +67,13 @@ SYSCALL_DEFINE6(32_mmap2, unsigned long, addr, unsigned long, len,
 	unsigned long, prot, unsigned long, flags, unsigned long, fd,
 	unsigned long, pgoff)
 {
-	struct file * file = NULL;
 	unsigned long error;
 
 	error = -EINVAL;
 	if (pgoff & (~PAGE_MASK >> 12))
 		goto out;
-	pgoff >>= PAGE_SHIFT-12;
-
-	if (!(flags & MAP_ANONYMOUS)) {
-		error = -EBADF;
-		file = fget(fd);
-		if (!file)
-			goto out;
-	}
-	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
-
-	down_write(&current->mm->mmap_sem);
-	error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
-	up_write(&current->mm->mmap_sem);
-	if (file)
-		fput(file);
-
+	error = sys_mmap_pgoff(addr, len, prot, flags, fd,
+			       pgoff >> (PAGE_SHIFT-12));
 out:
 	return error;
 }
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index fe0d79805603..3f7f466190b4 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -93,7 +93,8 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 		 * We do not accept a shared mapping if it would violate
 		 * cache aliasing constraints.
 		 */
-		if ((flags & MAP_SHARED) && (addr & shm_align_mask))
+		if ((flags & MAP_SHARED) &&
+		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
 			return -EINVAL;
 		return addr;
 	}
@@ -129,31 +130,6 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	}
 }
 
-/* common code for old and new mmaps */
-static inline unsigned long
-do_mmap2(unsigned long addr, unsigned long len, unsigned long prot,
-        unsigned long flags, unsigned long fd, unsigned long pgoff)
-{
-	unsigned long error = -EBADF;
-	struct file * file = NULL;
-
-	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
-	if (!(flags & MAP_ANONYMOUS)) {
-		file = fget(fd);
-		if (!file)
-			goto out;
-	}
-
-	down_write(&current->mm->mmap_sem);
-	error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
-	up_write(&current->mm->mmap_sem);
-
-	if (file)
-		fput(file);
-out:
-	return error;
-}
-
 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
 	unsigned long, prot, unsigned long, flags, unsigned long,
 	fd, off_t, offset)
@@ -164,7 +140,7 @@ SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
 	if (offset & ~PAGE_MASK)
 		goto out;
 
-	result = do_mmap2(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
+	result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
 
 out:
 	return result;
@@ -177,7 +153,7 @@ SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
 	if (pgoff & (~PAGE_MASK >> 12))
 		return -EINVAL;
 
-	return do_mmap2(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
+	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
 }
 
 save_static_function(sys_fork);