From: Mike Snitzer Date: Tue, 25 Oct 2016 14:46:23 +0000 (-0600) Subject: brd: remove support for BLKFLSBUF X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=ff26956875c2f05e12ecec9938411a2c7dfc767d;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git brd: remove support for BLKFLSBUF Discontinue having the brd driver destructively free all pages in the ramdisk in response to the BLKFLSBUF ioctl. Doing so allows a BLKFLSBUF ioctl issued to a logical partition to destroy pages of the parent brd device (and all other partitions of that brd device). This change breaks compatibility - but in this case the compatibility breaks more than it helps. Reported-by: Mikulas Patocka Suggested-by: Christoph Hellwig Signed-off-by: Mike Snitzer Signed-off-by: Jens Axboe --- diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 9d5335857191..ad793f35632c 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -395,44 +395,9 @@ static long brd_direct_access(struct block_device *bdev, sector_t sector, #define brd_direct_access NULL #endif -static int brd_ioctl(struct block_device *bdev, fmode_t mode, - unsigned int cmd, unsigned long arg) -{ - int error; - struct brd_device *brd = bdev->bd_disk->private_data; - - if (cmd != BLKFLSBUF) - return -ENOTTY; - - /* - * ram device BLKFLSBUF has special semantics, we want to actually - * release and destroy the ramdisk data. - */ - mutex_lock(&brd_mutex); - mutex_lock(&bdev->bd_mutex); - error = -EBUSY; - if (bdev->bd_openers <= 1) { - /* - * Kill the cache first, so it isn't written back to the - * device. - * - * Another thread might instantiate more buffercache here, - * but there is not much we can do to close that race. - */ - kill_bdev(bdev); - brd_free_pages(brd); - error = 0; - } - mutex_unlock(&bdev->bd_mutex); - mutex_unlock(&brd_mutex); - - return error; -} - static const struct block_device_operations brd_fops = { .owner = THIS_MODULE, .rw_page = brd_rw_page, - .ioctl = brd_ioctl, .direct_access = brd_direct_access, };