xen/blk[front|back]: Squash blkif_request_rw and blkif_request_discard together

In a union type structure to deal with the overlapping
attributes in a easier manner.

Suggested-by: Ian Campbell <Ian.Campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Konrad Rzeszutek Wilk
2011-10-12 12:12:36 -04:00
parent cfcfc9eca2
commit 97e36834f5
4 changed files with 88 additions and 67 deletions

View File

@@ -95,6 +95,12 @@ typedef uint64_t blkif_sector_t;
#define BLKIF_MAX_SEGMENTS_PER_REQUEST 11
struct blkif_request_rw {
uint8_t nr_segments; /* number of segments */
blkif_vdev_t handle; /* only for read/write requests */
#ifdef CONFIG_X86_64
uint32_t _pad1; /* offsetof(blkif_request,u.rw.id) == 8 */
#endif
uint64_t id; /* private guest value, echoed in resp */
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
struct blkif_request_segment {
grant_ref_t gref; /* reference to I/O buffer frame */
@@ -102,23 +108,27 @@ struct blkif_request_rw {
/* @last_sect: last sector in frame to transfer (inclusive). */
uint8_t first_sect, last_sect;
} seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
} __attribute__((__packed__));
struct blkif_request_discard {
uint8_t nr_segments; /* number of segments */
blkif_vdev_t _pad1; /* only for read/write requests */
#ifdef CONFIG_X86_64
uint32_t _pad2; /* offsetof(blkif_req..,u.discard.id)==8*/
#endif
uint64_t id; /* private guest value, echoed in resp */
blkif_sector_t sector_number;
uint64_t nr_sectors;
};
uint64_t nr_sectors;
uint8_t _pad3;
} __attribute__((__packed__));
struct blkif_request {
uint8_t operation; /* BLKIF_OP_??? */
uint8_t nr_segments; /* number of segments */
blkif_vdev_t handle; /* only for read/write requests */
uint64_t id; /* private guest value, echoed in resp */
union {
struct blkif_request_rw rw;
struct blkif_request_discard discard;
} u;
};
} __attribute__((__packed__));
struct blkif_response {
uint64_t id; /* copied from request */