Re: [PATCH 2/4] loop: Factor out configuring loop from status.

From: Bart Van Assche
Date: Mon Apr 20 2020 - 09:34:30 EST


On 4/20/20 1:04 AM, Martijn Coenen wrote:

No trailing dot at the end of a patch subject please.

static int
-loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
+loop_set_from_status(struct loop_device *lo, const struct loop_info64 *info)
{
int err;
struct loop_func_table *xfer;
kuid_t uid = current_uid();
+
+ if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
+ return -EINVAL;
+
+ err = loop_release_xfer(lo);
+ if (err)
+ return err;
+
+ if (info->lo_encrypt_type) {
+ unsigned int type = info->lo_encrypt_type;
+
+ if (type >= MAX_LO_CRYPT)
+ return -EINVAL;
+ xfer = xfer_funcs[type];
+ if (xfer == NULL)
+ return -EINVAL;
+ } else
+ xfer = NULL;
+
+ err = loop_init_xfer(lo, xfer, info);
+ if (err)
+ return err;
+
+ lo->lo_offset = info->lo_offset;
+ lo->lo_sizelimit = info->lo_sizelimit;
+ memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
+ memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
+ lo->lo_file_name[LO_NAME_SIZE-1] = 0;
+ lo->lo_crypt_name[LO_NAME_SIZE-1] = 0;
+
+ if (!xfer)
+ xfer = &none_funcs;
+ lo->transfer = xfer->transfer;
+ lo->ioctl = xfer->ioctl;
+
+ if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) !=
+ (info->lo_flags & LO_FLAGS_AUTOCLEAR))
+ lo->lo_flags ^= LO_FLAGS_AUTOCLEAR;
+
+ lo->lo_encrypt_key_size = info->lo_encrypt_key_size;
+ lo->lo_init[0] = info->lo_init[0];
+ lo->lo_init[1] = info->lo_init[1];
+ if (info->lo_encrypt_key_size) {
+ memcpy(lo->lo_encrypt_key, info->lo_encrypt_key,
+ info->lo_encrypt_key_size);
+ lo->lo_key_owner = uid;
+ }
+
+ return 0;
+}

Please add a (one line?) comment above this function that explains the purpose of this function. Is the purpose of this function perhaps to initialize loop device parameters based on the information received from user space (the 'info' argument)?

Thanks,

Bart.