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path: root/drivers/block/xen-blkback/common.h
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Diffstat (limited to 'drivers/block/xen-blkback/common.h')
-rw-r--r--drivers/block/xen-blkback/common.h98
1 files changed, 93 insertions, 5 deletions
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index e33fafa..1ac53da 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -50,6 +50,19 @@
__func__, __LINE__, ##args)
+/*
+ * This is the maximum number of segments that would be allowed in indirect
+ * requests. This value will also be passed to the frontend.
+ */
+#define MAX_INDIRECT_SEGMENTS 256
+
+#define SEGS_PER_INDIRECT_FRAME \
+ (PAGE_SIZE/sizeof(struct blkif_request_segment_aligned))
+#define MAX_INDIRECT_PAGES \
+ ((MAX_INDIRECT_SEGMENTS + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
+#define INDIRECT_PAGES(_segs) \
+ ((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
+
/* Not a real protocol. Used to generate ring structs which contain
* the elements common to all protocols only. This way we get a
* compiler-checkable way to use common struct elements, so we can
@@ -83,12 +96,31 @@ struct blkif_x86_32_request_other {
uint64_t id; /* private guest value, echoed in resp */
} __attribute__((__packed__));
+struct blkif_x86_32_request_indirect {
+ uint8_t indirect_op;
+ uint16_t nr_segments;
+ uint64_t id;
+ blkif_sector_t sector_number;
+ blkif_vdev_t handle;
+ uint16_t _pad1;
+ grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
+ /*
+ * The maximum number of indirect segments (and pages) that will
+ * be used is determined by MAX_INDIRECT_SEGMENTS, this value
+ * is also exported to the guest (via xenstore
+ * feature-max-indirect-segments entry), so the frontend knows how
+ * many indirect segments the backend supports.
+ */
+ uint64_t _pad2; /* make it 64 byte aligned */
+} __attribute__((__packed__));
+
struct blkif_x86_32_request {
uint8_t operation; /* BLKIF_OP_??? */
union {
struct blkif_x86_32_request_rw rw;
struct blkif_x86_32_request_discard discard;
struct blkif_x86_32_request_other other;
+ struct blkif_x86_32_request_indirect indirect;
} u;
} __attribute__((__packed__));
@@ -127,12 +159,32 @@ struct blkif_x86_64_request_other {
uint64_t id; /* private guest value, echoed in resp */
} __attribute__((__packed__));
+struct blkif_x86_64_request_indirect {
+ uint8_t indirect_op;
+ uint16_t nr_segments;
+ uint32_t _pad1; /* offsetof(blkif_..,u.indirect.id)==8 */
+ uint64_t id;
+ blkif_sector_t sector_number;
+ blkif_vdev_t handle;
+ uint16_t _pad2;
+ grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
+ /*
+ * The maximum number of indirect segments (and pages) that will
+ * be used is determined by MAX_INDIRECT_SEGMENTS, this value
+ * is also exported to the guest (via xenstore
+ * feature-max-indirect-segments entry), so the frontend knows how
+ * many indirect segments the backend supports.
+ */
+ uint32_t _pad3; /* make it 64 byte aligned */
+} __attribute__((__packed__));
+
struct blkif_x86_64_request {
uint8_t operation; /* BLKIF_OP_??? */
union {
struct blkif_x86_64_request_rw rw;
struct blkif_x86_64_request_discard discard;
struct blkif_x86_64_request_other other;
+ struct blkif_x86_64_request_indirect indirect;
} u;
} __attribute__((__packed__));
@@ -266,6 +318,11 @@ struct xen_blkif {
wait_queue_head_t waiting_to_free;
};
+struct seg_buf {
+ unsigned long offset;
+ unsigned int nsec;
+};
+
/*
* Each outstanding request that we've passed to the lower device layers has a
* 'pending_req' allocated to it. Each buffer_head that completes decrements
@@ -280,9 +337,16 @@ struct pending_req {
unsigned short operation;
int status;
struct list_head free_list;
- struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
- struct persistent_gnt *persistent_gnts[BLKIF_MAX_SEGMENTS_PER_REQUEST];
- grant_handle_t grant_handles[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct page *pages[MAX_INDIRECT_SEGMENTS];
+ struct persistent_gnt *persistent_gnts[MAX_INDIRECT_SEGMENTS];
+ grant_handle_t grant_handles[MAX_INDIRECT_SEGMENTS];
+ grant_ref_t grefs[MAX_INDIRECT_SEGMENTS];
+ /* Indirect descriptors */
+ struct persistent_gnt *indirect_persistent_gnts[MAX_INDIRECT_PAGES];
+ struct page *indirect_pages[MAX_INDIRECT_PAGES];
+ grant_handle_t indirect_handles[MAX_INDIRECT_PAGES];
+ struct seg_buf seg[MAX_INDIRECT_SEGMENTS];
+ struct bio *biolist[MAX_INDIRECT_SEGMENTS];
};
@@ -321,7 +385,7 @@ struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
static inline void blkif_get_x86_32_req(struct blkif_request *dst,
struct blkif_x86_32_request *src)
{
- int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j;
dst->operation = src->operation;
switch (src->operation) {
case BLKIF_OP_READ:
@@ -344,6 +408,18 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst,
dst->u.discard.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
+ case BLKIF_OP_INDIRECT:
+ dst->u.indirect.indirect_op = src->u.indirect.indirect_op;
+ dst->u.indirect.nr_segments = src->u.indirect.nr_segments;
+ dst->u.indirect.handle = src->u.indirect.handle;
+ dst->u.indirect.id = src->u.indirect.id;
+ dst->u.indirect.sector_number = src->u.indirect.sector_number;
+ barrier();
+ j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments));
+ for (i = 0; i < j; i++)
+ dst->u.indirect.indirect_grefs[i] =
+ src->u.indirect.indirect_grefs[i];
+ break;
default:
/*
* Don't know how to translate this op. Only get the
@@ -357,7 +433,7 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst,
static inline void blkif_get_x86_64_req(struct blkif_request *dst,
struct blkif_x86_64_request *src)
{
- int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j;
dst->operation = src->operation;
switch (src->operation) {
case BLKIF_OP_READ:
@@ -380,6 +456,18 @@ static inline void blkif_get_x86_64_req(struct blkif_request *dst,
dst->u.discard.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
+ case BLKIF_OP_INDIRECT:
+ dst->u.indirect.indirect_op = src->u.indirect.indirect_op;
+ dst->u.indirect.nr_segments = src->u.indirect.nr_segments;
+ dst->u.indirect.handle = src->u.indirect.handle;
+ dst->u.indirect.id = src->u.indirect.id;
+ dst->u.indirect.sector_number = src->u.indirect.sector_number;
+ barrier();
+ j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments));
+ for (i = 0; i < j; i++)
+ dst->u.indirect.indirect_grefs[i] =
+ src->u.indirect.indirect_grefs[i];
+ break;
default:
/*
* Don't know how to translate this op. Only get the
generated by cgit v1.1 at 2024-12-23 13:13:49 +0000