loop: fix ioctl calls using compat_loop_info

Support for cryptoloop was deleted in commit 47e9624616c8 ("block:
remove support for cryptoloop and the xor transfer"), making the usage
of loop_info->lo_encrypt_type obsolete. However, this member was also
removed from the compat_loop_info definition and this breaks userspace
ioctl calls for 32-bit binaries and CONFIG_COMPAT=y.

This patch restores the compat_loop_info->lo_encrypt_type member and
marks it obsolete as well as in the uapi header definitions.

Fixes: 47e9624616c8 ("block: remove support for cryptoloop and the xor transfer")
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220329201815.1347500-1-cmllamas@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index e733c48de2e907e0c6d87429a2870aa88cd7eba5..39e7650f89b12ae02bd186db0e324ac0e7a62a40 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1592,6 +1592,7 @@ struct compat_loop_info {
        compat_ulong_t  lo_inode;       /* ioctl r/o */
        compat_dev_t    lo_rdevice;     /* ioctl r/o */
        compat_int_t    lo_offset;
+       compat_int_t    lo_encrypt_type;        /* obsolete, ignored */
        compat_int_t    lo_encrypt_key_size;    /* ioctl w/o */
        compat_int_t    lo_flags;       /* ioctl r/o */
        char            lo_name[LO_NAME_SIZE];

diff --git a/include/uapi/linux/loop.h b/include/uapi/linux/loop.h
index 24a1c45bd1ae2a41b945cc77e7474ba2d6617ee5..98e60801195e29a5e38d7f2b2b3fb40d39d34364 100644 (file)
--- a/include/uapi/linux/loop.h
+++ b/include/uapi/linux/loop.h
@@ -45,7 +45,7 @@ struct loop_info {
        unsigned long      lo_inode;            /* ioctl r/o */
        __kernel_old_dev_t lo_rdevice;          /* ioctl r/o */
        int                lo_offset;
-       int                lo_encrypt_type;
+       int                lo_encrypt_type;             /* obsolete, ignored */
        int                lo_encrypt_key_size;         /* ioctl w/o */
        int                lo_flags;
        char               lo_name[LO_NAME_SIZE];
@@ -61,7 +61,7 @@ struct loop_info64 {
        __u64              lo_offset;
        __u64              lo_sizelimit;/* bytes, 0 == max available */
        __u32              lo_number;                   /* ioctl r/o */
-       __u32              lo_encrypt_type;
+       __u32              lo_encrypt_type;             /* obsolete, ignored */
        __u32              lo_encrypt_key_size;         /* ioctl w/o */
        __u32              lo_flags;
        __u8               lo_file_name[LO_NAME_SIZE];