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| author | Christoph Hellwig <hch@lst.de> | 2015-01-14 10:42:32 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-01-20 14:02:58 -0700 |
| commit | b4caecd48005fbed3949dde6c1cb233142fd69e9 (patch) | |
| tree | 1fdd9b7c15568c79eb3c1ed84a39858ddbcbc88b /fs/char_dev.c | |
| parent | 97b713ba3ebaa6c8d84c2c720f5468a7c6a6eb4e (diff) | |
| download | linux-b4caecd48005fbed3949dde6c1cb233142fd69e9.tar.bz2 | |
fs: introduce f_op->mmap_capabilities for nommu mmap support
Since "BDI: Provide backing device capability information [try #3]" the
backing_dev_info structure also provides flags for the kind of mmap
operation available in a nommu environment, which is entirely unrelated
to it's original purpose.
Introduce a new nommu-only file operation to provide this information to
the nommu mmap code instead. Splitting this from the backing_dev_info
structure allows to remove lots of backing_dev_info instance that aren't
otherwise needed, and entirely gets rid of the concept of providing a
backing_dev_info for a character device. It also removes the need for
the mtd_inodefs filesystem.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tejun Heo <tj@kernel.org>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'fs/char_dev.c')
| -rw-r--r-- | fs/char_dev.c | 24 |
1 files changed, 0 insertions, 24 deletions
diff --git a/fs/char_dev.c b/fs/char_dev.c index 67b2007f10fe..ea06a3d0364c 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -24,27 +24,6 @@ #include "internal.h" -/* - * 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 = { - .name = "char", - .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 | - /* no writeback happens */ - BDI_CAP_NO_ACCT_AND_WRITEBACK), -}; - static struct kobj_map *cdev_map; static DEFINE_MUTEX(chrdevs_lock); @@ -575,8 +554,6 @@ static struct kobject *base_probe(dev_t dev, int *part, void *data) void __init chrdev_init(void) { cdev_map = kobj_map_init(base_probe, &chrdevs_lock); - if (bdi_init(&directly_mappable_cdev_bdi)) - panic("Failed to init directly mappable cdev bdi"); } @@ -590,4 +567,3 @@ EXPORT_SYMBOL(cdev_del); EXPORT_SYMBOL(cdev_add); EXPORT_SYMBOL(__register_chrdev); EXPORT_SYMBOL(__unregister_chrdev); -EXPORT_SYMBOL(directly_mappable_cdev_bdi); |