[PATCH 19/26] block: Kill bio_segments()

Kent Overstreet
2013-06-09T02:22:30Z

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.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com>
Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
---
drivers/block/ps3disk.c | 7 ++---
drivers/md/bcache/io.c | 54 ++++++++++++++------------------
drivers/message/fusion/mptsas.c | 8 ++---
drivers/scsi/libsas/sas_expander.c | 8 ++---
drivers/scsi/mpt2sas/mpt2sas_transport.c | 10 +++---
drivers/scsi/mpt3sas/mpt3sas_transport.c | 8 ++---
include/linux/bio.h | 3 +-
7 files changed, 45 insertions(+), 53 deletions(-)

diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index 464be78..8d1a19c 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -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);
diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c
index 4224cfd..e3c582d 100644
--- a/drivers/md/bcache/io.c
+++ b/drivers/md/bcache/io.c
@@ -11,40 +11,32 @@

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);
-
- if (bio_segments(bio) > max_segments ||
- q->merge_bvec_fn) {
- struct bio_vec bv;
- struct bvec_iter iter;
- unsigned seg = 0;
-
- ret = 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,
- };
-
- 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;
- }
+ return min(bio_sectors(bio), q->limits.max_discard_sectors);
+
+ 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 (seg == min_t(unsigned, BIO_MAX_PAGES,
+ queue_max_segments(q)))
+ break;
+
+ if (q->merge_bvec_fn &&
+ q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len)
+ break;
+
+ seg++;
+ ret += bv.bv_len >> 9;
}

ret = min(ret, queue_max_sectors(q));
diff --git a/drivers/message/fusion/mptsas.c b/drivers/message/fusion/mptsas.c
index dd239bd..00d339c 100644
--- a/drivers/message/fusion/mptsas.c
+++ b/drivers/message/fusion/mptsas.c
@@ -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;
}

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 446b851..0cac7d8 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -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;
}

diff --git a/drivers/scsi/mpt2sas/mpt2sas_transport.c b/drivers/scsi/mpt2sas/mpt2sas_transport.c
index 2c2e01e..d2224b5 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_transport.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_transport.c
@@ -1940,7 +1940,7 @@ _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 */
@@ -1972,7 +1972,7 @@ _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) {
@@ -2039,7 +2039,7 @@ _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 {
@@ -2055,7 +2055,7 @@ _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 {
@@ -2100,7 +2100,7 @@ _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);
diff --git a/drivers/scsi/mpt3sas/mpt3sas_transport.c b/drivers/scsi/mpt3sas/mpt3sas_transport.c
index dd15b2d..3898f51 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_transport.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_transport.c
@@ -1923,7 +1923,7 @@ _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 */
@@ -1955,7 +1955,7 @@ _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) {
@@ -2016,7 +2016,7 @@ _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
@@ -2061,7 +2061,7 @@ _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);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 6767622..aa015ee 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -90,7 +90,8 @@
#define bio_offset(bio) bio_offset_iter((bio), (bio)->bi_iter)
#define bio_iovec(bio) bio_iovec_iter((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)))

--
1.8.3.rc1