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block/scsi: Provide a limit on the number of integrity segments

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Some controllers have a hardware limit on the number of protection
information scatter-gather list segments they can handle.

Introduce a max_integrity_segments limit in the block layer and provide
a new scsi_host_template setting that allows HBA drivers to provide a
value suitable for the hardware.

Add support for honoring the integrity segment limit when merging both
bios and requests.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>
This commit is contained in:
Martin K. Petersen 2010-09-10 20:50:10 +02:00 committed by Jens Axboe
parent c8bf133682
commit 13f05c8d8e
12 changed files with 167 additions and 50 deletions
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93
block/blk-integrity.c
View File

@ -32,24 +32,37 @@ static struct kmem_cache *integrity_cachep;
/**
* blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
* @rq: request with integrity metadata attached
* @q: request queue
* @bio: bio with integrity metadata attached
*
* Description: Returns the number of elements required in a
* scatterlist corresponding to the integrity metadata in a request.
* scatterlist corresponding to the integrity metadata in a bio.
*/
int blk_rq_count_integrity_sg(struct request *rq)
int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)
{
struct bio_vec *iv, *ivprv;
struct req_iterator iter;
unsigned int segments;
struct bio_vec *iv, *ivprv = NULL;
unsigned int segments = 0;
unsigned int seg_size = 0;
unsigned int i = 0;
ivprv = NULL;
segments = 0;
bio_for_each_integrity_vec(iv, bio, i) {
rq_for_each_integrity_segment(iv, rq, iter) {
if (ivprv) {
if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv))
goto new_segment;
if (!ivprv || !BIOVEC_PHYS_MERGEABLE(ivprv, iv))
if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv))
goto new_segment;
if (seg_size + iv->bv_len > queue_max_segment_size(q))
goto new_segment;
seg_size += iv->bv_len;
} else {
new_segment:
segments++;
seg_size = iv->bv_len;
}
ivprv = iv;
}
@ -60,30 +73,34 @@ EXPORT_SYMBOL(blk_rq_count_integrity_sg);
/**
* blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
* @rq: request with integrity metadata attached
* @q: request queue
* @bio: bio with integrity metadata attached
* @sglist: target scatterlist
*
* Description: Map the integrity vectors in request into a
* scatterlist. The scatterlist must be big enough to hold all
* elements. I.e. sized using blk_rq_count_integrity_sg().
*/
int blk_rq_map_integrity_sg(struct request *rq, struct scatterlist *sglist)
int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio,
struct scatterlist *sglist)
{
struct bio_vec *iv, *ivprv;
struct req_iterator iter;
struct scatterlist *sg;
unsigned int segments;
struct bio_vec *iv, *ivprv = NULL;
struct scatterlist *sg = NULL;
unsigned int segments = 0;
unsigned int i = 0;
ivprv = NULL;
sg = NULL;
segments = 0;
rq_for_each_integrity_segment(iv, rq, iter) {
bio_for_each_integrity_vec(iv, bio, i) {
if (ivprv) {
if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv))
goto new_segment;
if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv))
goto new_segment;
if (sg->length + iv->bv_len > queue_max_segment_size(q))
goto new_segment;
sg->length += iv->bv_len;
} else {
new_segment:
@ -162,6 +179,40 @@ int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2)
}
EXPORT_SYMBOL(blk_integrity_compare);
int blk_integrity_merge_rq(struct request_queue *q, struct request *req,
struct request *next)
{
if (blk_integrity_rq(req) != blk_integrity_rq(next))
return -1;
if (req->nr_integrity_segments + next->nr_integrity_segments >
q->limits.max_integrity_segments)
return -1;
return 0;
}
EXPORT_SYMBOL(blk_integrity_merge_rq);
int blk_integrity_merge_bio(struct request_queue *q, struct request *req,
struct bio *bio)
{
int nr_integrity_segs;
struct bio *next = bio->bi_next;
bio->bi_next = NULL;
nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
bio->bi_next = next;
if (req->nr_integrity_segments + nr_integrity_segs >
q->limits.max_integrity_segments)
return -1;
req->nr_integrity_segments += nr_integrity_segs;
return 0;
}
EXPORT_SYMBOL(blk_integrity_merge_bio);
struct integrity_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct blk_integrity *, char *);

23
block/blk-merge.c
View File

@ -205,12 +205,11 @@ static inline int ll_new_hw_segment(struct request_queue *q,
{
int nr_phys_segs = bio_phys_segments(q, bio);
if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) {
req->cmd_flags |= REQ_NOMERGE;
if (req == q->last_merge)
q->last_merge = NULL;
return 0;
}
if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q))
goto no_merge;
if (bio_integrity(bio) && blk_integrity_merge_bio(q, req, bio))
goto no_merge;
/*
* This will form the start of a new hw segment. Bump both
@ -218,6 +217,12 @@ static inline int ll_new_hw_segment(struct request_queue *q,
*/
req->nr_phys_segments += nr_phys_segs;
return 1;
no_merge:
req->cmd_flags |= REQ_NOMERGE;
if (req == q->last_merge)
q->last_merge = NULL;
return 0;
}
int ll_back_merge_fn(struct request_queue *q, struct request *req,
@ -301,6 +306,9 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
if (total_phys_segments > queue_max_segments(q))
return 0;
if (blk_integrity_rq(req) && blk_integrity_merge_rq(q, req, next))
return 0;
/* Merge is OK... */
req->nr_phys_segments = total_phys_segments;
return 1;
@ -372,9 +380,6 @@ static int attempt_merge(struct request_queue *q, struct request *req,
|| next->special)
return 0;
if (blk_integrity_rq(req) != blk_integrity_rq(next))
return 0;
/*
* If we are allowed to merge, then append bio list
* from next to rq and release next. merge_requests_fn

3
block/blk-settings.c
View File

@ -111,6 +111,7 @@ EXPORT_SYMBOL_GPL(blk_queue_lld_busy);
void blk_set_default_limits(struct queue_limits *lim)
{
lim->max_segments = BLK_MAX_SEGMENTS;
lim->max_integrity_segments = 0;
lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
lim->max_sectors = BLK_DEF_MAX_SECTORS;
@ -509,6 +510,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
b->seg_boundary_mask);
t->max_segments = min_not_zero(t->max_segments, b->max_segments);
t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
b->max_integrity_segments);
t->max_segment_size = min_not_zero(t->max_segment_size,
b->max_segment_size);

11
block/blk-sysfs.c
View File

@ -112,6 +112,11 @@ static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
return queue_var_show(queue_max_segments(q), (page));
}
static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
{
return queue_var_show(q->limits.max_integrity_segments, (page));
}
static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
{
if (test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
@ -288,6 +293,11 @@ static struct queue_sysfs_entry queue_max_segments_entry = {
.show = queue_max_segments_show,
};
static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
.attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
.show = queue_max_integrity_segments_show,
};
static struct queue_sysfs_entry queue_max_segment_size_entry = {
.attr = {.name = "max_segment_size", .mode = S_IRUGO },
.show = queue_max_segment_size_show,
@ -375,6 +385,7 @@ static struct attribute *default_attrs[] = {
&queue_max_hw_sectors_entry.attr,
&queue_max_sectors_entry.attr,
&queue_max_segments_entry.attr,
&queue_max_integrity_segments_entry.attr,
&queue_max_segment_size_entry.attr,
&queue_iosched_entry.attr,
&queue_hw_sector_size_entry.attr,

8
block/blk.h
View File

@ -132,14 +132,6 @@ static inline int queue_congestion_off_threshold(struct request_queue *q)
return q->nr_congestion_off;
}
#if defined(CONFIG_BLK_DEV_INTEGRITY)
#define rq_for_each_integrity_segment(bvl, _rq, _iter) \
__rq_for_each_bio(_iter.bio, _rq) \
bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
#endif /* BLK_DEV_INTEGRITY */
static inline int blk_cpu_to_group(int cpu)
{
#ifdef CONFIG_SCHED_MC

1
drivers/scsi/hosts.c
View File

@ -376,6 +376,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
shost->this_id = sht->this_id;
shost->can_queue = sht->can_queue;
shost->sg_tablesize = sht->sg_tablesize;
shost->sg_prot_tablesize = sht->sg_prot_tablesize;
shost->cmd_per_lun = sht->cmd_per_lun;
shost->unchecked_isa_dma = sht->unchecked_isa_dma;
shost->use_clustering = sht->use_clustering;

26
drivers/scsi/scsi_lib.c
View File

@ -968,11 +968,13 @@ static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
*/
int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
{
int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask);
struct request *rq = cmd->request;
int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask);
if (error)
goto err_exit;
if (blk_bidi_rq(cmd->request)) {
if (blk_bidi_rq(rq)) {
struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
scsi_sdb_cache, GFP_ATOMIC);
if (!bidi_sdb) {
@ -980,28 +982,28 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
goto err_exit;
}
cmd->request->next_rq->special = bidi_sdb;
error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb,
GFP_ATOMIC);
rq->next_rq->special = bidi_sdb;
error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC);
if (error)
goto err_exit;
}
if (blk_integrity_rq(cmd->request)) {
if (blk_integrity_rq(rq)) {
struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
int ivecs, count;
BUG_ON(prot_sdb == NULL);
ivecs = blk_rq_count_integrity_sg(cmd->request);
ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
error = BLKPREP_DEFER;
goto err_exit;
}
count = blk_rq_map_integrity_sg(cmd->request,
count = blk_rq_map_integrity_sg(rq->q, rq->bio,
prot_sdb->table.sgl);
BUG_ON(unlikely(count > ivecs));
BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
cmd->prot_sdb = prot_sdb;
cmd->prot_sdb->table.nents = count;
@ -1625,6 +1627,14 @@ struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
SCSI_MAX_SG_CHAIN_SEGMENTS));
if (scsi_host_prot_dma(shost)) {
shost->sg_prot_tablesize =
min_not_zero(shost->sg_prot_tablesize,
(unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
}
blk_queue_max_hw_sectors(q, shost->max_sectors);
blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
blk_queue_segment_boundary(q, shost->dma_boundary);

2
drivers/scsi/scsi_sysfs.c
View File

@ -251,6 +251,7 @@ shost_rd_attr(host_busy, "%hu\n");
shost_rd_attr(cmd_per_lun, "%hd\n");
shost_rd_attr(can_queue, "%hd\n");
shost_rd_attr(sg_tablesize, "%hu\n");
shost_rd_attr(sg_prot_tablesize, "%hu\n");
shost_rd_attr(unchecked_isa_dma, "%d\n");
shost_rd_attr(prot_capabilities, "%u\n");
shost_rd_attr(prot_guard_type, "%hd\n");
@ -262,6 +263,7 @@ static struct attribute *scsi_sysfs_shost_attrs[] = {
&dev_attr_cmd_per_lun.attr,
&dev_attr_can_queue.attr,
&dev_attr_sg_tablesize.attr,
&dev_attr_sg_prot_tablesize.attr,
&dev_attr_unchecked_isa_dma.attr,
&dev_attr_proc_name.attr,
&dev_attr_scan.attr,

4
include/linux/bio.h
View File

@ -496,6 +496,10 @@ static inline struct bio *bio_list_get(struct bio_list *bl)
#define bip_for_each_vec(bvl, bip, i) \
__bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
#define bio_for_each_integrity_vec(_bvl, _bio, _iter) \
for_each_bio(_bio) \
bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
#define bio_integrity(bio) (bio->bi_integrity != NULL)
extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);

33
include/linux/blkdev.h
View File

@ -124,6 +124,9 @@ struct request {
* physical address coalescing is performed.
*/
unsigned short nr_phys_segments;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
unsigned short nr_integrity_segments;
#endif
unsigned short ioprio;
@ -243,6 +246,7 @@ struct queue_limits {
unsigned short logical_block_size;
unsigned short max_segments;
unsigned short max_integrity_segments;
unsigned char misaligned;
unsigned char discard_misaligned;
@ -1213,8 +1217,13 @@ struct blk_integrity {
extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
extern void blk_integrity_unregister(struct gendisk *);
extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
extern int blk_rq_map_integrity_sg(struct request *, struct scatterlist *);
extern int blk_rq_count_integrity_sg(struct request *);
extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
struct scatterlist *);
extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
struct request *);
extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
struct bio *);
static inline
struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
@ -1235,16 +1244,32 @@ static inline int blk_integrity_rq(struct request *rq)
return bio_integrity(rq->bio);
}
static inline void blk_queue_max_integrity_segments(struct request_queue *q,
unsigned int segs)
{
q->limits.max_integrity_segments = segs;
}
static inline unsigned short
queue_max_integrity_segments(struct request_queue *q)
{
return q->limits.max_integrity_segments;
}
#else /* CONFIG_BLK_DEV_INTEGRITY */
#define blk_integrity_rq(rq) (0)
#define blk_rq_count_integrity_sg(a) (0)
#define blk_rq_map_integrity_sg(a, b) (0)
#define blk_rq_count_integrity_sg(a, b) (0)
#define blk_rq_map_integrity_sg(a, b, c) (0)
#define bdev_get_integrity(a) (0)
#define blk_get_integrity(a) (0)
#define blk_integrity_compare(a, b) (0)
#define blk_integrity_register(a, b) (0)
#define blk_integrity_unregister(a) do { } while (0);
#define blk_queue_max_integrity_segments(a, b) do { } while (0);
#define queue_max_integrity_segments(a) (0)
#define blk_integrity_merge_rq(a, b, c) (0)
#define blk_integrity_merge_bio(a, b, c) (0)
#endif /* CONFIG_BLK_DEV_INTEGRITY */

6
include/scsi/scsi.h
View File

@ -31,6 +31,12 @@ struct scsi_cmnd;
#define SCSI_MAX_SG_CHAIN_SEGMENTS SCSI_MAX_SG_SEGMENTS
#endif
/*
* DIX-capable adapters effectively support infinite chaining for the
* protection information scatterlist
*/
#define SCSI_MAX_PROT_SG_SEGMENTS 0xFFFF
/*
* Special value for scanning to specify scanning or rescanning of all
* possible channels, (target) ids, or luns on a given shost.

7
include/scsi/scsi_host.h
View File

@ -388,6 +388,7 @@ struct scsi_host_template {
* of scatter-gather.
*/
unsigned short sg_tablesize;
unsigned short sg_prot_tablesize;
/*
* Set this if the host adapter has limitations beside segment count.
@ -599,6 +600,7 @@ struct Scsi_Host {
int can_queue;
short cmd_per_lun;
short unsigned int sg_tablesize;
short unsigned int sg_prot_tablesize;
short unsigned int max_sectors;
unsigned long dma_boundary;
/*
@ -823,6 +825,11 @@ static inline unsigned int scsi_host_get_prot(struct Scsi_Host *shost)
return shost->prot_capabilities;
}
static inline int scsi_host_prot_dma(struct Scsi_Host *shost)
{
return shost->prot_capabilities >= SHOST_DIX_TYPE0_PROTECTION;
}
static inline unsigned int scsi_host_dif_capable(struct Scsi_Host *shost, unsigned int target_type)
{
static unsigned char cap[] = { 0,