On Tue, Aug 17, 2021 at 03:44:20PM +0530, SelvaKumar S wrote: > From: Nitesh Shetty <[email protected]> > > Add new BLKCOPY ioctl that offloads copying of one or more sources ranges > to a destination in the device. COPY ioctl accepts a 'copy_range' > structure that contains destination (in sectors), no of sources and > pointer to the array of source ranges. Each source range is represented by > 'range_entry' that contains start and length of source ranges (in sectors) > > MAX_COPY_NR_RANGE, limits the number of entries for the IOCTL and > MAX_COPY_TOTAL_LENGTH limits the total copy length, IOCTL can handle. > > Example code, to issue BLKCOPY: > /* Sample example to copy three source-ranges [0, 8] [16, 8] [32,8] to > * [64,24], on the same device */ > > int main(void) > { > int ret, fd; > struct range_entry source_range[] = {{.src = 0, .len = 8}, > {.src = 16, .len = 8}, {.src = 32, .len = 8},}; > struct copy_range cr; > > cr.dest = 64; > cr.nr_range = 3; > cr.range_list = (__u64)&source_range; > > fd = open("/dev/nvme0n1", O_RDWR); > if (fd < 0) return 1; > > ret = ioctl(fd, BLKCOPY, &cr); > if (ret < 0) printf("copy failure\n"); > > close(fd); > > return ret; > } > > Signed-off-by: Nitesh Shetty <[email protected]> > Signed-off-by: SelvaKumar S <[email protected]> > Signed-off-by: Kanchan Joshi <[email protected]> > --- > block/ioctl.c | 33 +++++++++++++++++++++++++++++++++ > include/uapi/linux/fs.h | 8 ++++++++ > 2 files changed, 41 insertions(+) > > diff --git a/block/ioctl.c b/block/ioctl.c > index eb0491e90b9a..2af56d01e9fe 100644 > --- a/block/ioctl.c > +++ b/block/ioctl.c > @@ -143,6 +143,37 @@ static int blk_ioctl_discard(struct block_device *bdev, > fmode_t mode, > GFP_KERNEL, flags); > } > > +static int blk_ioctl_copy(struct block_device *bdev, fmode_t mode, > + unsigned long arg) > +{ > + struct copy_range crange; > + struct range_entry *rlist; > + int ret; > + > + if (!(mode & FMODE_WRITE)) > + return -EBADF; > + > + if (copy_from_user(&crange, (void __user *)arg, sizeof(crange))) > + return -EFAULT; > + > + rlist = kmalloc_array(crange.nr_range, sizeof(*rlist), > + GFP_KERNEL);
No error checking for huge values of nr_range? Is that wise? You really want userspace to be able to allocate "all" of the kernel memory in the system? thanks, greg k-h -- dm-devel mailing list [email protected] https://listman.redhat.com/mailman/listinfo/dm-devel
