On Sun, Mar 15, 2020 at 10:05:21PM +0100, mwilck@xxxxxxxx wrote:
> From: Martin Wilck <mwilck@xxxxxxxx>
>
> Make sure that data structures used for PERSISTENT RESERVE IN/OUT
> fit into 8k buffers.
>
> This patch breaks the libmpathpersist ABI, because the offsets of
> struct print_fulldescr_list.descriptors and of the fields num_transportid and
> trnptid_list in struct prout_param_descriptor change.
I agree with the idea of holding off on this unless we actually bump the
version number on libmpathpersist
-Ben
>
> Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
> ---
> libmpathpersist/mpath_persist.h | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/libmpathpersist/mpath_persist.h b/libmpathpersist/mpath_persist.h
> index 7cf4faf9..bdf4069d 100644
> --- a/libmpathpersist/mpath_persist.h
> +++ b/libmpathpersist/mpath_persist.h
> @@ -92,7 +92,7 @@ struct prin_readdescr
> uint32_t prgeneration;
> uint32_t additional_length; /* The value should be either 0 or divisible by 8.
> 0 indicates no registered reservation key. */
> - uint8_t key_list[MPATH_MAX_PARAM_LEN];
> + uint8_t key_list[MPATH_MAX_PARAM_LEN - 2 * sizeof(uint32_t)];
> };
>
> struct prin_resvdescr
> @@ -141,7 +141,9 @@ struct print_fulldescr_list
> {
> uint32_t prgeneration;
> uint32_t number_of_descriptor;
> - uint8_t private_buffer[MPATH_MAX_PARAM_LEN]; /*Private buffer for list storage*/
> + /* Data-in; Private buffer for list storage */
> + uint8_t private_buffer[MPATH_MAX_PARAM_LEN - 2 * sizeof(uint32_t)];
> + /* array of pointers into private_buffer */
> struct prin_fulldescr *descriptors[];
> };
>
> @@ -163,8 +165,13 @@ struct prout_param_descriptor { /* PROUT parameter descriptor */
> uint8_t sa_flags;
> uint8_t _reserved;
> uint16_t _obsolete1;
> - uint8_t private_buffer[MPATH_MAX_PARAM_LEN]; /*private buffer for list storage*/
> - uint32_t num_transportid; /* Number of Transport ID listed in trnptid_list[]*/
> + /*private buffer for list storage; data-out */
> + /* 24: offsetof (struct prout_param_descriptor, private_buffer) */
> + uint8_t private_buffer[MPATH_MAX_PARAM_LEN - 24];
> + /* Internal use below here */
> + /* Number of Transport ID listed in trnptid_list[] */
> + uint32_t num_transportid;
> + /* pointers into private_buffer */
> struct transportid *trnptid_list[];
> };
>
> --
> 2.25.1
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