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rbd: move from raw pages to bvec data descriptors
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In preparation for rbd "fancy" striping which requires bio_vec arrays,
wire up BVECS data type and kill off PAGES data type.  There is nothing
wrong with using page vectors for copyup requests -- it's just less
iterator boilerplate code to write for the new striping framework.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
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Ilya Dryomov committed Apr 2, 2018
1 parent b9e281c commit 7e07efb
Showing 1 changed file with 77 additions and 78 deletions.
155 changes: 77 additions & 78 deletions drivers/block/rbd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -219,7 +219,7 @@ typedef void (*rbd_obj_callback_t)(struct rbd_obj_request *);
enum obj_request_type {
OBJ_REQUEST_NODATA = 1,
OBJ_REQUEST_BIO, /* pointer into provided bio (list) */
OBJ_REQUEST_PAGES,
OBJ_REQUEST_BVECS, /* pointer into provided bio_vec array */
};

enum obj_operation_type {
Expand Down Expand Up @@ -272,12 +272,12 @@ struct rbd_obj_request {
union {
struct ceph_bio_iter bio_pos;
struct {
struct page **pages;
u32 page_count;
struct ceph_bvec_iter bvec_pos;
u32 bvec_count;
};
};
struct page **copyup_pages;
u32 copyup_page_count;
struct bio_vec *copyup_bvecs;
u32 copyup_bvec_count;

struct ceph_osd_request *osd_req;

Expand Down Expand Up @@ -1272,36 +1272,14 @@ static void zero_bios(struct ceph_bio_iter *bio_pos, u32 off, u32 bytes)
}));
}

/*
* similar to zero_bio_chain(), zeros data defined by a page array,
* starting at the given byte offset from the start of the array and
* continuing up to the given end offset. The pages array is
* assumed to be big enough to hold all bytes up to the end.
*/
static void zero_pages(struct page **pages, u64 offset, u64 end)
static void zero_bvecs(struct ceph_bvec_iter *bvec_pos, u32 off, u32 bytes)
{
struct page **page = &pages[offset >> PAGE_SHIFT];

rbd_assert(end > offset);
rbd_assert(end - offset <= (u64)SIZE_MAX);
while (offset < end) {
size_t page_offset;
size_t length;
unsigned long flags;
void *kaddr;

page_offset = offset & ~PAGE_MASK;
length = min_t(size_t, PAGE_SIZE - page_offset, end - offset);
local_irq_save(flags);
kaddr = kmap_atomic(*page);
memset(kaddr + page_offset, 0, length);
flush_dcache_page(*page);
kunmap_atomic(kaddr);
local_irq_restore(flags);
struct ceph_bvec_iter it = *bvec_pos;

offset += length;
page++;
}
ceph_bvec_iter_advance(&it, off);
ceph_bvec_iter_advance_step(&it, bytes, ({
zero_bvec(&bv);
}));
}

/*
Expand Down Expand Up @@ -1461,7 +1439,7 @@ static bool obj_request_type_valid(enum obj_request_type type)
switch (type) {
case OBJ_REQUEST_NODATA:
case OBJ_REQUEST_BIO:
case OBJ_REQUEST_PAGES:
case OBJ_REQUEST_BVECS:
return true;
default:
return false;
Expand Down Expand Up @@ -1611,14 +1589,15 @@ rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request)
if (obj_request->type == OBJ_REQUEST_BIO)
zero_bios(&obj_request->bio_pos, 0, length);
else
zero_pages(obj_request->pages, 0, length);
zero_bvecs(&obj_request->bvec_pos, 0, length);
obj_request->result = 0;
} else if (xferred < length && !obj_request->result) {
if (obj_request->type == OBJ_REQUEST_BIO)
zero_bios(&obj_request->bio_pos, xferred,
length - xferred);
else
zero_pages(obj_request->pages, xferred, length);
zero_bvecs(&obj_request->bvec_pos, xferred,
length - xferred);
}
obj_request->xferred = length;
obj_request_done_set(obj_request);
Expand Down Expand Up @@ -1913,6 +1892,7 @@ rbd_obj_request_create(enum obj_request_type type)
static void rbd_obj_request_destroy(struct kref *kref)
{
struct rbd_obj_request *obj_request;
u32 i;

obj_request = container_of(kref, struct rbd_obj_request, kref);

Expand All @@ -1924,22 +1904,22 @@ static void rbd_obj_request_destroy(struct kref *kref)
if (obj_request->osd_req)
rbd_osd_req_destroy(obj_request->osd_req);

rbd_assert(obj_request_type_valid(obj_request->type));
switch (obj_request->type) {
case OBJ_REQUEST_NODATA:
case OBJ_REQUEST_BIO:
case OBJ_REQUEST_BVECS:
break; /* Nothing to do */
case OBJ_REQUEST_PAGES:
/* img_data requests don't own their page array */
if (obj_request->pages &&
!obj_request_img_data_test(obj_request))
ceph_release_page_vector(obj_request->pages,
obj_request->page_count);
break;
default:
rbd_assert(0);
}

ceph_release_page_vector(obj_request->copyup_pages,
obj_request->copyup_page_count);
if (obj_request->copyup_bvecs) {
for (i = 0; i < obj_request->copyup_bvec_count; i++) {
if (obj_request->copyup_bvecs[i].bv_page)
__free_page(obj_request->copyup_bvecs[i].bv_page);
}
kfree(obj_request->copyup_bvecs);
}

kmem_cache_free(rbd_obj_request_cache, obj_request);
}
Expand Down Expand Up @@ -2260,10 +2240,9 @@ static void rbd_img_obj_request_fill(struct rbd_obj_request *obj_request,
if (obj_request->type == OBJ_REQUEST_BIO)
osd_req_op_extent_osd_data_bio(osd_request, num_ops,
&obj_request->bio_pos, length);
else if (obj_request->type == OBJ_REQUEST_PAGES)
osd_req_op_extent_osd_data_pages(osd_request, num_ops,
obj_request->pages, length,
offset & ~PAGE_MASK, false, false);
else if (obj_request->type == OBJ_REQUEST_BVECS)
osd_req_op_extent_osd_data_bvec_pos(osd_request, num_ops,
&obj_request->bvec_pos);

/* Discards are also writes */
if (op_type == OBJ_OP_WRITE || op_type == OBJ_OP_DISCARD)
Expand All @@ -2288,7 +2267,7 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
struct rbd_obj_request *obj_request = NULL;
struct rbd_obj_request *next_obj_request;
struct ceph_bio_iter bio_it;
struct page **pages = NULL;
struct ceph_bvec_iter bvec_it;
enum obj_operation_type op_type;
u64 img_offset;
u64 resid;
Expand All @@ -2305,8 +2284,8 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
bio_it = *(struct ceph_bio_iter *)data_desc;
rbd_assert(img_offset ==
bio_it.iter.bi_sector << SECTOR_SHIFT);
} else if (type == OBJ_REQUEST_PAGES) {
pages = data_desc;
} else if (type == OBJ_REQUEST_BVECS) {
bvec_it = *(struct ceph_bvec_iter *)data_desc;
}

while (resid) {
Expand All @@ -2332,15 +2311,10 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
if (type == OBJ_REQUEST_BIO) {
obj_request->bio_pos = bio_it;
ceph_bio_iter_advance(&bio_it, length);
} else if (type == OBJ_REQUEST_PAGES) {
unsigned int page_count;

obj_request->pages = pages;
page_count = (u32)calc_pages_for(offset, length);
obj_request->page_count = page_count;
if ((offset + length) & ~PAGE_MASK)
page_count--; /* more on last page */
pages += page_count;
} else if (type == OBJ_REQUEST_BVECS) {
obj_request->bvec_pos = bvec_it;
ceph_bvec_iter_shorten(&obj_request->bvec_pos, length);
ceph_bvec_iter_advance(&bvec_it, length);
}

osd_req = rbd_osd_req_create(rbd_dev, op_type,
Expand Down Expand Up @@ -2452,8 +2426,8 @@ rbd_img_obj_parent_read_full_callback(struct rbd_img_request *img_request)
/* Initialize the copyup op */

osd_req_op_cls_init(osd_req, 0, CEPH_OSD_OP_CALL, "rbd", "copyup");
osd_req_op_cls_request_data_pages(osd_req, 0, orig_request->copyup_pages,
parent_length, 0, false, false);
osd_req_op_cls_request_data_bvecs(osd_req, 0, orig_request->copyup_bvecs,
parent_length);

/* Add the other op(s) */

Expand All @@ -2469,6 +2443,8 @@ rbd_img_obj_parent_read_full_callback(struct rbd_img_request *img_request)
rbd_obj_request_error(orig_request, img_result);
}

static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap);

/*
* Read from the parent image the range of data that covers the
* entire target of the given object request. This is used for
Expand All @@ -2487,10 +2463,9 @@ static int rbd_img_obj_parent_read_full(struct rbd_obj_request *obj_request)
{
struct rbd_device *rbd_dev = obj_request->img_request->rbd_dev;
struct rbd_img_request *parent_request = NULL;
struct ceph_bvec_iter bvec_it = { 0 };
u64 img_offset;
u64 length;
struct page **pages = NULL;
u32 page_count;
int result;

rbd_assert(rbd_dev->parent != NULL);
Expand All @@ -2516,24 +2491,20 @@ static int rbd_img_obj_parent_read_full(struct rbd_obj_request *obj_request)
* Allocate a page array big enough to receive the data read
* from the parent.
*/
page_count = (u32)calc_pages_for(0, length);
pages = ceph_alloc_page_vector(page_count, GFP_NOIO);
if (IS_ERR(pages)) {
result = PTR_ERR(pages);
result = setup_copyup_bvecs(obj_request, length);
if (result)
goto out_err;
}

rbd_assert(!obj_request->copyup_pages);
obj_request->copyup_pages = pages;
obj_request->copyup_page_count = page_count;

result = -ENOMEM;
parent_request = rbd_parent_request_create(obj_request,
img_offset, length);
if (!parent_request)
goto out_err;

result = rbd_img_request_fill(parent_request, OBJ_REQUEST_PAGES, pages);
bvec_it.bvecs = obj_request->copyup_bvecs;
bvec_it.iter.bi_size = length;
result = rbd_img_request_fill(parent_request, OBJ_REQUEST_BVECS,
&bvec_it);
if (result)
goto out_err;

Expand Down Expand Up @@ -2751,6 +2722,34 @@ static int rbd_img_request_submit(struct rbd_img_request *img_request)
return ret;
}

static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
{
u32 i;

rbd_assert(!obj_req->copyup_bvecs);
obj_req->copyup_bvec_count = calc_pages_for(0, obj_overlap);
obj_req->copyup_bvecs = kcalloc(obj_req->copyup_bvec_count,
sizeof(*obj_req->copyup_bvecs),
GFP_NOIO);
if (!obj_req->copyup_bvecs)
return -ENOMEM;

for (i = 0; i < obj_req->copyup_bvec_count; i++) {
unsigned int len = min(obj_overlap, (u64)PAGE_SIZE);

obj_req->copyup_bvecs[i].bv_page = alloc_page(GFP_NOIO);
if (!obj_req->copyup_bvecs[i].bv_page)
return -ENOMEM;

obj_req->copyup_bvecs[i].bv_offset = 0;
obj_req->copyup_bvecs[i].bv_len = len;
obj_overlap -= len;
}

rbd_assert(!obj_overlap);
return 0;
}

static void rbd_img_parent_read_callback(struct rbd_img_request *img_request)
{
struct rbd_obj_request *obj_request;
Expand Down Expand Up @@ -2832,8 +2831,8 @@ static void rbd_img_parent_read(struct rbd_obj_request *obj_request)
result = rbd_img_request_fill(img_request, OBJ_REQUEST_BIO,
&obj_request->bio_pos);
else
result = rbd_img_request_fill(img_request, OBJ_REQUEST_PAGES,
obj_request->pages);
result = rbd_img_request_fill(img_request, OBJ_REQUEST_BVECS,
&obj_request->bvec_pos);
if (result)
goto out_err;

Expand Down

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