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block: Kill bio_segments()/bi_vcnt usage 

When we start sharing biovecs, keeping bi_vcnt accurate for splits is
going to be error prone - and unnecessary, if we refactor some code.

So bio_segments() has to go - but most of the existing users just needed
to know if the bio had multiple segments, which is easier - add a
bio_multiple_segments() for them.

(Two of the current uses of bio_segments() are going to go away in a
couple patches, but the current implementation of bio_segments() is
unsafe as soon as we start doing driver conversions for immutable
biovecs - so implement a dumb version for bisectability, it'll go away
in a couple patches)

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Neil Brown <neilb@suse.de>
Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com>
Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
This commit is contained in:
Kent Overstreet 2013-09-24 16:26:05 -07:00
parent d57a5f7c66
commit 458b76ed2f
10 changed files with 93 additions and 86 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/block/ps3disk.c
View File

@ -101,10 +101,9 @@ static void ps3disk_scatter_gather(struct ps3_storage_device *dev,
rq_for_each_segment(bvec, req, iter) {
unsigned long flags;
dev_dbg(&dev->sbd.core,
"%s:%u: bio %u: %u segs %u sectors from %lu\n",
__func__, __LINE__, i, bio_segments(iter.bio),
bio_sectors(iter.bio), iter.bio->bi_iter.bi_sector);
dev_dbg(&dev->sbd.core, "%s:%u: bio %u: %u sectors from %lu\n",
__func__, __LINE__, i, bio_sectors(iter.bio),
iter.bio->bi_iter.bi_sector);
size = bvec.bv_len;
buf = bvec_kmap_irq(&bvec, &flags);

51
drivers/md/bcache/io.c
View File

@ -24,7 +24,8 @@ static void bch_generic_make_request_hack(struct bio *bio)
if (bio->bi_iter.bi_idx) {
struct bio_vec bv;
struct bvec_iter iter;
struct bio *clone = bio_alloc(GFP_NOIO, bio_segments(bio));
unsigned segs = bio_segments(bio);
struct bio *clone = bio_alloc(GFP_NOIO, segs);
bio_for_each_segment(bv, bio, iter)
clone->bi_io_vec[clone->bi_vcnt++] = bv;
@ -32,7 +33,7 @@ static void bch_generic_make_request_hack(struct bio *bio)
clone->bi_iter.bi_sector = bio->bi_iter.bi_sector;
clone->bi_bdev = bio->bi_bdev;
clone->bi_rw = bio->bi_rw;
clone->bi_vcnt = bio_segments(bio);
clone->bi_vcnt = segs;
clone->bi_iter.bi_size = bio->bi_iter.bi_size;
clone->bi_private = bio;
@ -133,40 +134,32 @@ out:
static unsigned bch_bio_max_sectors(struct bio *bio)
{
unsigned ret = bio_sectors(bio);
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
unsigned max_segments = min_t(unsigned, BIO_MAX_PAGES,
queue_max_segments(q));
struct bio_vec bv;
struct bvec_iter iter;
unsigned ret = 0, seg = 0;
if (bio->bi_rw & REQ_DISCARD)
return min(ret, q->limits.max_discard_sectors);
return min(bio_sectors(bio), q->limits.max_discard_sectors);
if (bio_segments(bio) > max_segments ||
q->merge_bvec_fn) {
struct bio_vec bv;
struct bvec_iter iter;
unsigned seg = 0;
bio_for_each_segment(bv, bio, iter) {
struct bvec_merge_data bvm = {
.bi_bdev = bio->bi_bdev,
.bi_sector = bio->bi_iter.bi_sector,
.bi_size = ret << 9,
.bi_rw = bio->bi_rw,
};
ret = 0;
if (seg == min_t(unsigned, BIO_MAX_PAGES,
queue_max_segments(q)))
break;
bio_for_each_segment(bv, bio, iter) {
struct bvec_merge_data bvm = {
.bi_bdev = bio->bi_bdev,
.bi_sector = bio->bi_iter.bi_sector,
.bi_size = ret << 9,
.bi_rw = bio->bi_rw,
};
if (q->merge_bvec_fn &&
q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len)
break;
if (seg == max_segments)
break;
if (q->merge_bvec_fn &&
q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len)
break;
seg++;
ret += bv.bv_len >> 9;
}
seg++;
ret += bv.bv_len >> 9;
}
ret = min(ret, queue_max_sectors(q));

2
drivers/md/raid0.c
View File

@ -528,7 +528,7 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio)
sector_t sector = bio->bi_iter.bi_sector;
struct bio_pair *bp;
/* Sanity check -- queue functions should prevent this happening */
if (bio_segments(bio) > 1)
if (bio_multiple_segments(bio))
goto bad_map;
/* This is a one page bio that upper layers
* refuse to split for us, so we need to split it.

2
drivers/md/raid10.c
View File

@ -1188,7 +1188,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
|| conf->prev.near_copies < conf->prev.raid_disks))) {
struct bio_pair *bp;
/* Sanity check -- queue functions should prevent this happening */
if (bio_segments(bio) > 1)
if (bio_multiple_segments(bio))
goto bad_map;
/* This is a one page bio that upper layers
* refuse to split for us, so we need to split it.

8
drivers/message/fusion/mptsas.c
View File

@ -2235,10 +2235,10 @@ static int mptsas_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
}
/* do we need to support multiple segments? */
if (bio_segments(req->bio) > 1 || bio_segments(rsp->bio) > 1) {
printk(MYIOC_s_ERR_FMT "%s: multiple segments req %u %u, rsp %u %u\n",
ioc->name, __func__, bio_segments(req->bio), blk_rq_bytes(req),
bio_segments(rsp->bio), blk_rq_bytes(rsp));
if (bio_multiple_segments(req->bio) ||
bio_multiple_segments(rsp->bio)) {
printk(MYIOC_s_ERR_FMT "%s: multiple segments req %u, rsp %u\n",
ioc->name, __func__, blk_rq_bytes(req), blk_rq_bytes(rsp));
return -EINVAL;
}

8
drivers/scsi/libsas/sas_expander.c
View File

@ -2163,10 +2163,10 @@ int sas_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
}
/* do we need to support multiple segments? */
if (bio_segments(req->bio) > 1 || bio_segments(rsp->bio) > 1) {
printk("%s: multiple segments req %u %u, rsp %u %u\n",
__func__, bio_segments(req->bio), blk_rq_bytes(req),
bio_segments(rsp->bio), blk_rq_bytes(rsp));
if (bio_multiple_segments(req->bio) ||
bio_multiple_segments(rsp->bio)) {
printk("%s: multiple segments req %u, rsp %u\n",
__func__, blk_rq_bytes(req), blk_rq_bytes(rsp));
return -EINVAL;
}

10
drivers/scsi/mpt2sas/mpt2sas_transport.c
View File

@ -1943,7 +1943,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
ioc->transport_cmds.status = MPT2_CMD_PENDING;
/* Check if the request is split across multiple segments */
if (bio_segments(req->bio) > 1) {
if (bio_multiple_segments(req->bio)) {
u32 offset = 0;
/* Allocate memory and copy the request */
@ -1975,7 +1975,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
/* Check if the response needs to be populated across
* multiple segments */
if (bio_segments(rsp->bio) > 1) {
if (bio_multiple_segments(rsp->bio)) {
pci_addr_in = pci_alloc_consistent(ioc->pdev, blk_rq_bytes(rsp),
&pci_dma_in);
if (!pci_addr_in) {
@ -2042,7 +2042,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
sgl_flags = (MPI2_SGE_FLAGS_SIMPLE_ELEMENT |
MPI2_SGE_FLAGS_END_OF_BUFFER | MPI2_SGE_FLAGS_HOST_TO_IOC);
sgl_flags = sgl_flags << MPI2_SGE_FLAGS_SHIFT;
if (bio_segments(req->bio) > 1) {
if (bio_multiple_segments(req->bio)) {
ioc->base_add_sg_single(psge, sgl_flags |
(blk_rq_bytes(req) - 4), pci_dma_out);
} else {
@ -2058,7 +2058,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
MPI2_SGE_FLAGS_LAST_ELEMENT | MPI2_SGE_FLAGS_END_OF_BUFFER |
MPI2_SGE_FLAGS_END_OF_LIST);
sgl_flags = sgl_flags << MPI2_SGE_FLAGS_SHIFT;
if (bio_segments(rsp->bio) > 1) {
if (bio_multiple_segments(rsp->bio)) {
ioc->base_add_sg_single(psge, sgl_flags |
(blk_rq_bytes(rsp) + 4), pci_dma_in);
} else {
@ -2103,7 +2103,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
le16_to_cpu(mpi_reply->ResponseDataLength);
/* check if the resp needs to be copied from the allocated
* pci mem */
if (bio_segments(rsp->bio) > 1) {
if (bio_multiple_segments(rsp->bio)) {
u32 offset = 0;
u32 bytes_to_copy =
le16_to_cpu(mpi_reply->ResponseDataLength);

8
drivers/scsi/mpt3sas/mpt3sas_transport.c
View File

@ -1926,7 +1926,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
ioc->transport_cmds.status = MPT3_CMD_PENDING;
/* Check if the request is split across multiple segments */
if (req->bio->bi_vcnt > 1) {
if (bio_multiple_segments(req->bio)) {
u32 offset = 0;
/* Allocate memory and copy the request */
@ -1958,7 +1958,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
/* Check if the response needs to be populated across
* multiple segments */
if (rsp->bio->bi_vcnt > 1) {
if (bio_multiple_segments(rsp->bio)) {
pci_addr_in = pci_alloc_consistent(ioc->pdev, blk_rq_bytes(rsp),
&pci_dma_in);
if (!pci_addr_in) {
@ -2019,7 +2019,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
mpi_request->RequestDataLength = cpu_to_le16(blk_rq_bytes(req) - 4);
psge = &mpi_request->SGL;
if (req->bio->bi_vcnt > 1)
if (bio_multiple_segments(req->bio))
ioc->build_sg(ioc, psge, pci_dma_out, (blk_rq_bytes(req) - 4),
pci_dma_in, (blk_rq_bytes(rsp) + 4));
else
@ -2064,7 +2064,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
/* check if the resp needs to be copied from the allocated
* pci mem */
if (rsp->bio->bi_vcnt > 1) {
if (bio_multiple_segments(rsp->bio)) {
u32 offset = 0;
u32 bytes_to_copy =
le16_to_cpu(mpi_reply->ResponseDataLength);

2
fs/bio.c
View File

@ -1733,7 +1733,7 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors)
trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
bi->bi_iter.bi_sector + first_sectors);
BUG_ON(bio_segments(bi) > 1);
BUG_ON(bio_multiple_segments(bi));
atomic_set(&bp->cnt, 3);
bp->error = 0;
bp->bio1 = *bi;

81
include/linux/bio.h
View File

@ -97,13 +97,46 @@
#define bio_offset(bio) bio_iter_offset((bio), (bio)->bi_iter)
#define bio_iovec(bio) bio_iter_iovec((bio), (bio)->bi_iter)
#define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_iter.bi_idx)
#define bio_multiple_segments(bio) \
((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
#define bio_sectors(bio) ((bio)->bi_iter.bi_size >> 9)
#define bio_end_sector(bio) ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
/*
* Check whether this bio carries any data or not. A NULL bio is allowed.
*/
static inline bool bio_has_data(struct bio *bio)
{
if (bio &&
bio->bi_iter.bi_size &&
!(bio->bi_rw & REQ_DISCARD))
return true;
return false;
}
static inline bool bio_is_rw(struct bio *bio)
{
if (!bio_has_data(bio))
return false;
if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
return false;
return true;
}
static inline bool bio_mergeable(struct bio *bio)
{
if (bio->bi_rw & REQ_NOMERGE_FLAGS)
return false;
return true;
}
static inline unsigned int bio_cur_bytes(struct bio *bio)
{
if (bio->bi_vcnt)
if (bio_has_data(bio))
return bio_iovec(bio).bv_len;
else /* dataless requests such as discard */
return bio->bi_iter.bi_size;
@ -111,7 +144,7 @@ static inline unsigned int bio_cur_bytes(struct bio *bio)
static inline void *bio_data(struct bio *bio)
{
if (bio->bi_vcnt)
if (bio_has_data(bio))
return page_address(bio_page(bio)) + bio_offset(bio);
return NULL;
@ -221,6 +254,18 @@ static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
#define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
static inline unsigned bio_segments(struct bio *bio)
{
unsigned segs = 0;
struct bio_vec bv;
struct bvec_iter iter;
bio_for_each_segment(bv, bio, iter)
segs++;
return segs;
}
/*
* get a reference to a bio, so it won't disappear. the intended use is
* something like:
@ -434,36 +479,6 @@ static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
__bio_kmap_irq((bio), (bio)->bi_iter.bi_idx, (flags))
#define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
/*
* Check whether this bio carries any data or not. A NULL bio is allowed.
*/
static inline bool bio_has_data(struct bio *bio)
{
if (bio && bio->bi_vcnt)
return true;
return false;
}
static inline bool bio_is_rw(struct bio *bio)
{
if (!bio_has_data(bio))
return false;
if (bio->bi_rw & REQ_WRITE_SAME)
return false;
return true;
}
static inline bool bio_mergeable(struct bio *bio)
{
if (bio->bi_rw & REQ_NOMERGE_FLAGS)
return false;
return true;
}
/*
* BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
*