diff options
| -rw-r--r-- | drivers/block/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/block/brd.c | 39 |
2 files changed, 47 insertions, 2 deletions
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index 8be67cd3fe01..b6d230b3209f 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -357,6 +357,16 @@ config BLK_DEV_RAM_SIZE The default value is 4096 kilobytes. Only change this if you know what you are doing. +config BLK_DEV_XIP + bool "Support XIP filesystems on RAM block device" + depends on BLK_DEV_RAM + default n + help + Support XIP filesystems (such as ext2 with XIP support on) on + top of block ram device. This will slightly enlarge the kernel, and + will prevent RAM block device backing store memory from being + allocated from highmem (only a problem for highmem systems). + config CDROM_PKTCDVD tristate "Packet writing on CD/DVD media" depends on !UML diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 50b659bedc8f..85364804364f 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -89,6 +89,7 @@ static struct page *brd_insert_page(struct brd_device *brd, sector_t sector) { pgoff_t idx; struct page *page; + gfp_t gfp_flags; page = brd_lookup_page(brd, sector); if (page) @@ -97,7 +98,16 @@ static struct page *brd_insert_page(struct brd_device *brd, sector_t sector) /* * Must use NOIO because we don't want to recurse back into the * block or filesystem layers from page reclaim. + * + * Cannot support XIP and highmem, because our ->direct_access + * routine for XIP must return memory that is always addressable. + * If XIP was reworked to use pfns and kmap throughout, this + * restriction might be able to be lifted. */ + gfp_flags = GFP_NOIO | __GFP_ZERO; +#ifndef CONFIG_BLK_DEV_XIP + gfp_flags |= __GFP_HIGHMEM; +#endif page = alloc_page(GFP_NOIO | __GFP_HIGHMEM | __GFP_ZERO); if (!page) return NULL; @@ -307,6 +317,28 @@ out: return 0; } +#ifdef CONFIG_BLK_DEV_XIP +static int brd_direct_access (struct block_device *bdev, sector_t sector, + unsigned long *data) +{ + struct brd_device *brd = bdev->bd_disk->private_data; + struct page *page; + + if (!brd) + return -ENODEV; + if (sector & (PAGE_SECTORS-1)) + return -EINVAL; + if (sector + PAGE_SECTORS > get_capacity(bdev->bd_disk)) + return -ERANGE; + page = brd_insert_page(brd, sector); + if (!page) + return -ENOMEM; + *data = (unsigned long)page_address(page); + + return 0; +} +#endif + static int brd_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { @@ -342,8 +374,11 @@ static int brd_ioctl(struct inode *inode, struct file *file, } static struct block_device_operations brd_fops = { - .owner = THIS_MODULE, - .ioctl = brd_ioctl, + .owner = THIS_MODULE, + .ioctl = brd_ioctl, +#ifdef CONFIG_BLK_DEV_XIP + .direct_access = brd_direct_access, +#endif }; /* |