Re: [PATCH] loop: Add LOOP_SET_FD_WITH_OFFSET ioctl.
From: Bart Van Assche <bvanassche@acm.org>
Date: 2020-03-29 20:20:06
Also in:
lkml
On 2020-03-29 07:04, Martijn Coenen wrote:
-static int loop_set_fd(struct loop_device *lo, fmode_t mode, - struct block_device *bdev, unsigned int arg) +static int loop_set_fd_with_offset(struct loop_device *lo, fmode_t mode, + struct block_device *bdev, unsigned int arg, loff_t offset)
Since this function has to be modified, please add an additional patch to rename 'arg' into 'fd'. Additionally, how about renaming "loop_set_fd_with_offset" into "loop_set_fd_and_offset"? I think the latter name reflects more clearly the purpose of this function.
quoted hunk ↗ jump to hunk
@@ -1624,6 +1625,17 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode, break; case LOOP_GET_STATUS64: return loop_get_status64(lo, (struct loop_info64 __user *) arg); + case LOOP_SET_FD_WITH_OFFSET: { + struct loop_fd_with_offset fdwo; + + if (copy_from_user(&fdwo, + (struct loop_fd_with_offset __user *) arg, + sizeof(struct loop_fd_with_offset)))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The kernel code that I'm familiar with uses sizeof(<variable name>) instead of sizeof(<struct name>). That makes it less likely that changing the type of the variable will introduce a mismatch between the sizeof() expression and the size of the variable. Thanks, Bart.