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-   -   bounce: Refactor __blk_queue_bounce to not use bi_io_vec (http://www.linux-archive.org/device-mapper-development/702581-bounce-refactor-__blk_queue_bounce-not-use-bi_io_vec.html)

Kent Overstreet 09-11-2012 12:22 AM

bounce: Refactor __blk_queue_bounce to not use bi_io_vec
 
A bunch of what __blk_queue_bounce() was doing was problematic for the
immutable bvec work; this cleans that up and the code is quite a bit
smaller, too.

The __bio_for_each_segment() in copy_to_high_bio_irq() was changed
because that one's looping over the original bio, not the bounce bio -
since the bounce code doesn't own that bio the __ version wasn't
correct.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
mm/bounce.c | 73 ++++++++++++++++---------------------------------------------
1 file changed, 19 insertions(+), 54 deletions(-)

diff --git a/mm/bounce.c b/mm/bounce.c
index 0420867..3068300 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -101,7 +101,7 @@ static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
struct bio_vec *tovec, *fromvec;
int i;

- __bio_for_each_segment(tovec, to, i, 0) {
+ bio_for_each_segment(tovec, to, i) {
fromvec = from->bi_io_vec + i;

/*
@@ -181,78 +181,43 @@ static void bounce_end_io_read_isa(struct bio *bio, int err)
static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
mempool_t *pool)
{
- struct page *page;
- struct bio *bio = NULL;
- int i, rw = bio_data_dir(*bio_orig);
+ struct bio *bio;
+ int rw = bio_data_dir(*bio_orig);
struct bio_vec *to, *from;
+ unsigned i;

- bio_for_each_segment(from, *bio_orig, i) {
- page = from->bv_page;
+ bio_for_each_segment(from, *bio_orig, i)
+ if (page_to_pfn(from->bv_page) > queue_bounce_pfn(q))
+ goto bounce;

- /*
- * is destination page below bounce pfn?
- */
- if (page_to_pfn(page) <= queue_bounce_pfn(q))
- continue;
-
- /*
- * irk, bounce it
- */
- if (!bio) {
- unsigned int cnt = (*bio_orig)->bi_vcnt;
+ return;
+bounce:
+ bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);

- bio = bio_alloc(GFP_NOIO, cnt);
- memset(bio->bi_io_vec, 0, cnt * sizeof(struct bio_vec));
- }
-
+ bio_for_each_segment(to, bio, i) {
+ struct page *page = to->bv_page;

- to = bio->bi_io_vec + i;
+ if (page_to_pfn(page) <= queue_bounce_pfn(q))
+ continue;

- to->bv_page = mempool_alloc(pool, q->bounce_gfp);
- to->bv_len = from->bv_len;
- to->bv_offset = from->bv_offset;
inc_zone_page_state(to->bv_page, NR_BOUNCE);
+ to->bv_page = mempool_alloc(pool, q->bounce_gfp);

if (rw == WRITE) {
char *vto, *vfrom;

- flush_dcache_page(from->bv_page);
+ flush_dcache_page(page);
+
vto = page_address(to->bv_page) + to->bv_offset;
- vfrom = kmap(from->bv_page) + from->bv_offset;
+ vfrom = kmap_atomic(page) + to->bv_offset;
memcpy(vto, vfrom, to->bv_len);
- kunmap(from->bv_page);
+ kunmap_atomic(vfrom);
}
}

- /*
- * no pages bounced
- */
- if (!bio)
- return;
-
trace_block_bio_bounce(q, *bio_orig);

- /*
- * at least one page was bounced, fill in possible non-highmem
- * pages
- */
- __bio_for_each_segment(from, *bio_orig, i, 0) {
- to = bio_iovec_idx(bio, i);
- if (!to->bv_page) {
- to->bv_page = from->bv_page;
- to->bv_len = from->bv_len;
- to->bv_offset = from->bv_offset;
- }
- }
-
- bio->bi_bdev = (*bio_orig)->bi_bdev;
bio->bi_flags |= (1 << BIO_BOUNCED);
- bio->bi_sector = (*bio_orig)->bi_sector;
- bio->bi_rw = (*bio_orig)->bi_rw;
-
- bio->bi_vcnt = (*bio_orig)->bi_vcnt;
- bio->bi_idx = (*bio_orig)->bi_idx;
- bio->bi_size = (*bio_orig)->bi_size;

if (pool == page_pool) {
bio->bi_end_io = bounce_end_io_write;
--
1.7.12

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Kent Overstreet 09-24-2012 10:35 PM

bounce: Refactor __blk_queue_bounce to not use bi_io_vec
 
A bunch of what __blk_queue_bounce() was doing was problematic for the
immutable bvec work; this cleans that up and the code is quite a bit
smaller, too.

The __bio_for_each_segment() in copy_to_high_bio_irq() was changed
because that one's looping over the original bio, not the bounce bio -
a later patch renames __bio_for_each_segment() ->
bio_for_each_segment_all(), and documents that
bio_for_each_segment_all() is only for code that owns the bio.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
mm/bounce.c | 73 ++++++++++++++++---------------------------------------------
1 file changed, 19 insertions(+), 54 deletions(-)

diff --git a/mm/bounce.c b/mm/bounce.c
index 0420867..3068300 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -101,7 +101,7 @@ static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
struct bio_vec *tovec, *fromvec;
int i;

- __bio_for_each_segment(tovec, to, i, 0) {
+ bio_for_each_segment(tovec, to, i) {
fromvec = from->bi_io_vec + i;

/*
@@ -181,78 +181,43 @@ static void bounce_end_io_read_isa(struct bio *bio, int err)
static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
mempool_t *pool)
{
- struct page *page;
- struct bio *bio = NULL;
- int i, rw = bio_data_dir(*bio_orig);
+ struct bio *bio;
+ int rw = bio_data_dir(*bio_orig);
struct bio_vec *to, *from;
+ unsigned i;

- bio_for_each_segment(from, *bio_orig, i) {
- page = from->bv_page;
+ bio_for_each_segment(from, *bio_orig, i)
+ if (page_to_pfn(from->bv_page) > queue_bounce_pfn(q))
+ goto bounce;

- /*
- * is destination page below bounce pfn?
- */
- if (page_to_pfn(page) <= queue_bounce_pfn(q))
- continue;
-
- /*
- * irk, bounce it
- */
- if (!bio) {
- unsigned int cnt = (*bio_orig)->bi_vcnt;
+ return;
+bounce:
+ bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);

- bio = bio_alloc(GFP_NOIO, cnt);
- memset(bio->bi_io_vec, 0, cnt * sizeof(struct bio_vec));
- }
-
+ bio_for_each_segment(to, bio, i) {
+ struct page *page = to->bv_page;

- to = bio->bi_io_vec + i;
+ if (page_to_pfn(page) <= queue_bounce_pfn(q))
+ continue;

- to->bv_page = mempool_alloc(pool, q->bounce_gfp);
- to->bv_len = from->bv_len;
- to->bv_offset = from->bv_offset;
inc_zone_page_state(to->bv_page, NR_BOUNCE);
+ to->bv_page = mempool_alloc(pool, q->bounce_gfp);

if (rw == WRITE) {
char *vto, *vfrom;

- flush_dcache_page(from->bv_page);
+ flush_dcache_page(page);
+
vto = page_address(to->bv_page) + to->bv_offset;
- vfrom = kmap(from->bv_page) + from->bv_offset;
+ vfrom = kmap_atomic(page) + to->bv_offset;
memcpy(vto, vfrom, to->bv_len);
- kunmap(from->bv_page);
+ kunmap_atomic(vfrom);
}
}

- /*
- * no pages bounced
- */
- if (!bio)
- return;
-
trace_block_bio_bounce(q, *bio_orig);

- /*
- * at least one page was bounced, fill in possible non-highmem
- * pages
- */
- __bio_for_each_segment(from, *bio_orig, i, 0) {
- to = bio_iovec_idx(bio, i);
- if (!to->bv_page) {
- to->bv_page = from->bv_page;
- to->bv_len = from->bv_len;
- to->bv_offset = from->bv_offset;
- }
- }
-
- bio->bi_bdev = (*bio_orig)->bi_bdev;
bio->bi_flags |= (1 << BIO_BOUNCED);
- bio->bi_sector = (*bio_orig)->bi_sector;
- bio->bi_rw = (*bio_orig)->bi_rw;
-
- bio->bi_vcnt = (*bio_orig)->bi_vcnt;
- bio->bi_idx = (*bio_orig)->bi_idx;
- bio->bi_size = (*bio_orig)->bi_size;

if (pool == page_pool) {
bio->bi_end_io = bounce_end_io_write;
--
1.7.12

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Kent Overstreet 10-15-2012 08:08 PM

bounce: Refactor __blk_queue_bounce to not use bi_io_vec
 
A bunch of what __blk_queue_bounce() was doing was problematic for the
immutable bvec work; this cleans that up and the code is quite a bit
smaller, too.

The __bio_for_each_segment() in copy_to_high_bio_irq() was changed
because that one's looping over the original bio, not the bounce bio -
a later patch renames __bio_for_each_segment() ->
bio_for_each_segment_all(), and documents that
bio_for_each_segment_all() is only for code that owns the bio.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
mm/bounce.c | 73 ++++++++++++++++---------------------------------------------
1 file changed, 19 insertions(+), 54 deletions(-)

diff --git a/mm/bounce.c b/mm/bounce.c
index 0420867..3068300 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -101,7 +101,7 @@ static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
struct bio_vec *tovec, *fromvec;
int i;

- __bio_for_each_segment(tovec, to, i, 0) {
+ bio_for_each_segment(tovec, to, i) {
fromvec = from->bi_io_vec + i;

/*
@@ -181,78 +181,43 @@ static void bounce_end_io_read_isa(struct bio *bio, int err)
static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
mempool_t *pool)
{
- struct page *page;
- struct bio *bio = NULL;
- int i, rw = bio_data_dir(*bio_orig);
+ struct bio *bio;
+ int rw = bio_data_dir(*bio_orig);
struct bio_vec *to, *from;
+ unsigned i;

- bio_for_each_segment(from, *bio_orig, i) {
- page = from->bv_page;
+ bio_for_each_segment(from, *bio_orig, i)
+ if (page_to_pfn(from->bv_page) > queue_bounce_pfn(q))
+ goto bounce;

- /*
- * is destination page below bounce pfn?
- */
- if (page_to_pfn(page) <= queue_bounce_pfn(q))
- continue;
-
- /*
- * irk, bounce it
- */
- if (!bio) {
- unsigned int cnt = (*bio_orig)->bi_vcnt;
+ return;
+bounce:
+ bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);

- bio = bio_alloc(GFP_NOIO, cnt);
- memset(bio->bi_io_vec, 0, cnt * sizeof(struct bio_vec));
- }
-
+ bio_for_each_segment(to, bio, i) {
+ struct page *page = to->bv_page;

- to = bio->bi_io_vec + i;
+ if (page_to_pfn(page) <= queue_bounce_pfn(q))
+ continue;

- to->bv_page = mempool_alloc(pool, q->bounce_gfp);
- to->bv_len = from->bv_len;
- to->bv_offset = from->bv_offset;
inc_zone_page_state(to->bv_page, NR_BOUNCE);
+ to->bv_page = mempool_alloc(pool, q->bounce_gfp);

if (rw == WRITE) {
char *vto, *vfrom;

- flush_dcache_page(from->bv_page);
+ flush_dcache_page(page);
+
vto = page_address(to->bv_page) + to->bv_offset;
- vfrom = kmap(from->bv_page) + from->bv_offset;
+ vfrom = kmap_atomic(page) + to->bv_offset;
memcpy(vto, vfrom, to->bv_len);
- kunmap(from->bv_page);
+ kunmap_atomic(vfrom);
}
}

- /*
- * no pages bounced
- */
- if (!bio)
- return;
-
trace_block_bio_bounce(q, *bio_orig);

- /*
- * at least one page was bounced, fill in possible non-highmem
- * pages
- */
- __bio_for_each_segment(from, *bio_orig, i, 0) {
- to = bio_iovec_idx(bio, i);
- if (!to->bv_page) {
- to->bv_page = from->bv_page;
- to->bv_len = from->bv_len;
- to->bv_offset = from->bv_offset;
- }
- }
-
- bio->bi_bdev = (*bio_orig)->bi_bdev;
bio->bi_flags |= (1 << BIO_BOUNCED);
- bio->bi_sector = (*bio_orig)->bi_sector;
- bio->bi_rw = (*bio_orig)->bi_rw;
-
- bio->bi_vcnt = (*bio_orig)->bi_vcnt;
- bio->bi_idx = (*bio_orig)->bi_idx;
- bio->bi_size = (*bio_orig)->bi_size;

if (pool == page_pool) {
bio->bi_end_io = bounce_end_io_write;
--
1.7.12

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