The patch titled
NOMMU: Set BDI capabilities for /dev/mem and /dev/kmem
has been added to the -mm tree. Its filename is
nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: NOMMU: Set BDI capabilities for /dev/mem and /dev/kmem
From: David Howells <dhowells@xxxxxxxxxx>
Set the backing device info capabilities for /dev/mem and /dev/kmem to
permit direct sharing under no-MMU conditions and full mapping capabilities
under MMU conditions. Make the BDI used by these available to all directly
mappable character devices.
Also comment the capabilities for /dev/zero.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/char/mem.c | 33 +++++++++++++++++++++++++++++++++
fs/char_dev.c | 20 ++++++++++++++++++++
include/linux/cdev.h | 2 ++
3 files changed, 55 insertions(+)
diff -puN drivers/char/mem.c~nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem drivers/char/mem.c
--- a/drivers/char/mem.c~nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem
+++ a/drivers/char/mem.c
@@ -238,6 +238,19 @@ static pgprot_t phys_mem_access_prot(str
}
#endif
+#ifndef CONFIG_MMU
+static unsigned long get_unmapped_area_mem(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long pgoff,
+ unsigned long flags)
+{
+ if (!valid_mmap_phys_addr_range(pgoff, len))
+ return (unsigned long) -EINVAL;
+ return pgoff;
+}
+#endif
+
static int mmap_mem(struct file * file, struct vm_area_struct * vma)
{
size_t size = vma->vm_end - vma->vm_start;
@@ -245,6 +258,12 @@ static int mmap_mem(struct file * file,
if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
return -EINVAL;
+#ifndef CONFIG_MMU
+ /* can't do an in-place private mapping if there's no MMU */
+ if (!(vma->vm_flags & VM_MAYSHARE))
+ return -ENOSYS;
+#endif
+
vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
size,
vma->vm_page_prot);
@@ -782,6 +801,9 @@ static const struct file_operations mem_
.write = write_mem,
.mmap = mmap_mem,
.open = open_mem,
+#ifndef CONFIG_MMU
+ .get_unmapped_area = get_unmapped_area_mem,
+#endif
};
static const struct file_operations kmem_fops = {
@@ -790,6 +812,9 @@ static const struct file_operations kmem
.write = write_kmem,
.mmap = mmap_kmem,
.open = open_kmem,
+#ifndef CONFIG_MMU
+ .get_unmapped_area = get_unmapped_area_mem,
+#endif
};
static const struct file_operations null_fops = {
@@ -815,6 +840,10 @@ static const struct file_operations zero
.mmap = mmap_zero,
};
+/*
+ * capabilities for /dev/zero
+ * - permits private mappings, "copies" are taken of the source of zeros
+ */
static struct backing_dev_info zero_bdi = {
.capabilities = BDI_CAP_MAP_COPY,
};
@@ -862,9 +891,13 @@ static int memory_open(struct inode * in
switch (iminor(inode)) {
case 1:
filp->f_op = &mem_fops;
+ filp->f_mapping->backing_dev_info =
+ &directly_mappable_cdev_bdi;
break;
case 2:
filp->f_op = &kmem_fops;
+ filp->f_mapping->backing_dev_info =
+ &directly_mappable_cdev_bdi;
break;
case 3:
filp->f_op = &null_fops;
diff -puN fs/char_dev.c~nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem fs/char_dev.c
--- a/fs/char_dev.c~nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem
+++ a/fs/char_dev.c
@@ -19,11 +19,30 @@
#include <linux/kobj_map.h>
#include <linux/cdev.h>
#include <linux/mutex.h>
+#include <linux/backing-dev.h>
#ifdef CONFIG_KMOD
#include <linux/kmod.h>
#endif
+/*
+ * capabilities for /dev/mem, /dev/kmem and similar directly mappable character
+ * devices
+ * - permits shared-mmap for read, write and/or exec
+ * - does not permit private mmap in NOMMU mode (can't do COW)
+ * - no readahead or I/O queue unplugging required
+ */
+struct backing_dev_info directly_mappable_cdev_bdi = {
+ .capabilities = (
+#ifdef CONFIG_MMU
+ /* permit private copies of the data to be taken */
+ BDI_CAP_MAP_COPY |
+#endif
+ /* permit direct mmap, for read, write or exec */
+ BDI_CAP_MAP_DIRECT |
+ BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP),
+};
+
static struct kobj_map *cdev_map;
static DEFINE_MUTEX(chrdevs_lock);
@@ -538,3 +557,4 @@ EXPORT_SYMBOL(cdev_del);
EXPORT_SYMBOL(cdev_add);
EXPORT_SYMBOL(register_chrdev);
EXPORT_SYMBOL(unregister_chrdev);
+EXPORT_SYMBOL(directly_mappable_cdev_bdi);
diff -puN include/linux/cdev.h~nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem include/linux/cdev.h
--- a/include/linux/cdev.h~nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem
+++ a/include/linux/cdev.h
@@ -23,5 +23,7 @@ void cdev_del(struct cdev *);
void cd_forget(struct inode *);
+extern struct backing_dev_info directly_mappable_cdev_bdi;
+
#endif
#endif
_
Patches currently in -mm which might be from dhowells@xxxxxxxxxx are
git-gfs2.patch
git-nfs.patch
nfs-replace-null-dentries-that-appear-in-readdirs-list-2.patch
binfmt_elf-consistently-use-loff_t.patch
afs-add-lock-annotations-to-afs_proc_cell_servers_startstop.patch
elf_fdpic_core_dump-dont-take-tasklist_lock.patch
simplify-update_times-avoid-jiffies-jiffies_64-aliasing-problem-2.patch
lib-rwsemc-un-inline-rwsem_down_failed_common.patch
nommu-check-that-access_process_vm-has-a-valid-target.patch
nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem.patch
nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem-tidy.patch
reiserfs-make-sure-all-dentries-refs-are-released-before-calling-kill_block_super-try-2.patch
fs-cache-provide-a-filesystem-specific-syncable-page-bit.patch
fs-cache-generic-filesystem-caching-facility.patch
fs-cache-release-page-private-in-failed-readahead.patch
fs-cache-release-page-private-after-failed-readahead-12.patch
fs-cache-make-kafs-use-fs-cache.patch
fs-cache-make-kafs-use-fs-cache-fix.patch
fs-cache-make-kafs-use-fs-cache-12.patch
fs-cache-make-kafs-use-fs-cache-12-fix.patch
fs-cache-make-kafs-use-fs-cache-vs-streamline-generic_file_-interfaces-and-filemap.patch
nfs-use-local-caching.patch
nfs-use-local-caching-12.patch
nfs-use-local-caching-12-fix.patch
fs-cache-cachefiles-ia64-missing-copy_page-export.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-cachefiles-printk-format-warning.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-warning-fixes.patch
autofs-make-sure-all-dentries-refs-are-released-before-calling-kill_anon_super.patch
vfs-destroy-the-dentries-contributed-by-a-superblock-on-unmounting.patch
vfs-make-filldir_t-and-struct-kstat-deal-in-64-bit-inode-numbers.patch
vfs-make-filldir_t-and-struct-kstat-deal-in-64-bit-inode-numbers-alpha-fix.patch
nfs-represent-64-bit-fileids-as-64-bit-inode-numbers-on-32-bit-systems.patch
ecryptfs-get_sb_dev-fix.patch
block-move-functions-out-of-buffer-code.patch
block-remove-duplicate-declaration-of-exit_io_context.patch
block-stop-fallback_migrate_page-from-using-page_has_buffers.patch
block-separate-the-bounce-buffering-code-from-the-highmem-code.patch
block-dont-call-block_sync_page-from-afs.patch
block-move-extern-declarations-out-of-fs-c-into-header-files.patch
block-move-extern-declarations-out-of-fs-c-into-header-files-tidy.patch
block-remove-dependence-on-existence-of-blockdev_superblock.patch
block-remove-dependence-on-existence-of-blockdev_superblock-tidy.patch
block-dissociate-generic_writepages-from-mpage-stuff.patch
block-move-__invalidate_device-to-block_devc.patch
block-move-the-loop-device-ioctl-compat-stuff-to-the-loop-driver.patch
block-move-common-fs-specific-ioctls-to-linux-fsh.patch
block-move-the-reiserfs-device-ioctl-compat-stuff-to-the-reiserfs-driver.patch
block-move-the-ext2-device-ioctl-compat-stuff-to-the-ext2-driver.patch
block-move-the-ext3-device-ioctl-compat-stuff-to-the-ext3-driver.patch
block-move-the-msdos-device-ioctl-compat-stuff-to-the-msdos-driver.patch
block-remove-no-longer-necessary-linux-mpageh-inclusions.patch
block-remove-no-longer-necessary-linux-buffer_headh-inclusions.patch
block-make-usb-storage-depend-on-scsi-rather-than-selecting-it.patch
block-make-it-possible-to-disable-the-block-layer.patch
block-make-it-possible-to-disable-the-block-layer-tidy.patch
block-make-it-possible-to-disable-the-block-layer-tidy-fix.patch
reiser4-get_sb_dev-fix.patch
mutex-subsystem-synchro-test-module.patch
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