rbd: small changes
Here is another set of small code tidy-ups:
- Define SECTOR_SHIFT and SECTOR_SIZE, and use these symbolic
names throughout. Tell the blk_queue system our physical
block size, in the (unlikely) event we want to use something
other than the default.
- Delete the definition of struct rbd_info, which is never used.
- Move the definition of dev_to_rbd() down in its source file,
just above where it gets first used, and change its name to
dev_to_rbd_dev().
- Replace an open-coded operation in rbd_dev_release() to use
dev_to_rbd_dev() instead.
- Calculate the segment size for a given rbd_device just once in
rbd_init_disk().
- Use the '%zd' conversion specifier in rbd_snap_size_show(),
since the value formatted is a size_t.
- Switch to the '%llu' conversion specifier in rbd_snap_id_show().
since the value formatted is unsigned.
Signed-off-by: Alex Elder <elder@dreamhost.com>
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index a42b28e..568fa5b 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -41,6 +41,15 @@
#include "rbd_types.h"
+/*
+ * The basic unit of block I/O is a sector. It is interpreted in a
+ * number of contexts in Linux (blk, bio, genhd), but the default is
+ * universally 512 bytes. These symbols are just slightly more
+ * meaningful than the bare numbers they represent.
+ */
+#define SECTOR_SHIFT 9
+#define SECTOR_SIZE (1ULL << SECTOR_SHIFT)
+
#define RBD_DRV_NAME "rbd"
#define RBD_DRV_NAME_LONG "rbd (rados block device)"
@@ -221,11 +230,6 @@
};
-static struct rbd_device *dev_to_rbd(struct device *dev)
-{
- return container_of(dev, struct rbd_device, dev);
-}
-
static struct device *rbd_get_dev(struct rbd_device *rbd_dev)
{
return get_device(&rbd_dev->dev);
@@ -743,7 +747,7 @@
/* split the bio. We'll release it either in the next
call, or it will have to be released outside */
- bp = bio_split(old_chain, (len - total) / 512ULL);
+ bp = bio_split(old_chain, (len - total) / SECTOR_SIZE);
if (!bp)
goto err_out;
@@ -1471,7 +1475,7 @@
do_write = (rq_data_dir(rq) == WRITE);
size = blk_rq_bytes(rq);
- ofs = blk_rq_pos(rq) * 512ULL;
+ ofs = blk_rq_pos(rq) * SECTOR_SIZE;
rq_bio = rq->bio;
if (do_write && rbd_dev->read_only) {
__blk_end_request_all(rq, -EROFS);
@@ -1482,7 +1486,7 @@
dout("%s 0x%x bytes at 0x%llx\n",
do_write ? "write" : "read",
- size, blk_rq_pos(rq) * 512ULL);
+ size, blk_rq_pos(rq) * SECTOR_SIZE);
num_segs = rbd_get_num_segments(&rbd_dev->header, ofs, size);
coll = rbd_alloc_coll(num_segs);
@@ -1547,13 +1551,17 @@
struct bio_vec *bvec)
{
struct rbd_device *rbd_dev = q->queuedata;
- unsigned int chunk_sectors = 1 << (rbd_dev->header.obj_order - 9);
- sector_t sector = bmd->bi_sector + get_start_sect(bmd->bi_bdev);
- unsigned int bio_sectors = bmd->bi_size >> 9;
+ unsigned int chunk_sectors;
+ sector_t sector;
+ unsigned int bio_sectors;
int max;
+ chunk_sectors = 1 << (rbd_dev->header.obj_order - SECTOR_SHIFT);
+ sector = bmd->bi_sector + get_start_sect(bmd->bi_bdev);
+ bio_sectors = bmd->bi_size >> SECTOR_SHIFT;
+
max = (chunk_sectors - ((sector & (chunk_sectors - 1))
- + bio_sectors)) << 9;
+ + bio_sectors)) << SECTOR_SHIFT;
if (max < 0)
max = 0; /* bio_add cannot handle a negative return */
if (max <= bvec->bv_len && bio_sectors == 0)
@@ -1708,7 +1716,7 @@
return ret;
/* resized? */
- set_capacity(rbd_dev->disk, h.image_size / 512ULL);
+ set_capacity(rbd_dev->disk, h.image_size / SECTOR_SIZE);
down_write(&rbd_dev->header.snap_rwsem);
@@ -1745,6 +1753,7 @@
struct gendisk *disk;
struct request_queue *q;
int rc;
+ u64 segment_size;
u64 total_size = 0;
/* contact OSD, request size info about the object being mapped */
@@ -1780,11 +1789,15 @@
if (!q)
goto out_disk;
+ /* We use the default size, but let's be explicit about it. */
+ blk_queue_physical_block_size(q, SECTOR_SIZE);
+
/* set io sizes to object size */
- blk_queue_max_hw_sectors(q, rbd_obj_bytes(&rbd_dev->header) / 512ULL);
- blk_queue_max_segment_size(q, rbd_obj_bytes(&rbd_dev->header));
- blk_queue_io_min(q, rbd_obj_bytes(&rbd_dev->header));
- blk_queue_io_opt(q, rbd_obj_bytes(&rbd_dev->header));
+ segment_size = rbd_obj_bytes(&rbd_dev->header);
+ blk_queue_max_hw_sectors(q, segment_size / SECTOR_SIZE);
+ blk_queue_max_segment_size(q, segment_size);
+ blk_queue_io_min(q, segment_size);
+ blk_queue_io_opt(q, segment_size);
blk_queue_merge_bvec(q, rbd_merge_bvec);
disk->queue = q;
@@ -1795,7 +1808,7 @@
rbd_dev->q = q;
/* finally, announce the disk to the world */
- set_capacity(disk, total_size / 512ULL);
+ set_capacity(disk, total_size / SECTOR_SIZE);
add_disk(disk);
pr_info("%s: added with size 0x%llx\n",
@@ -1812,10 +1825,15 @@
sysfs
*/
+static struct rbd_device *dev_to_rbd_dev(struct device *dev)
+{
+ return container_of(dev, struct rbd_device, dev);
+}
+
static ssize_t rbd_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct rbd_device *rbd_dev = dev_to_rbd(dev);
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
return sprintf(buf, "%llu\n", (unsigned long long)rbd_dev->header.image_size);
}
@@ -1823,7 +1841,7 @@
static ssize_t rbd_major_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct rbd_device *rbd_dev = dev_to_rbd(dev);
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
return sprintf(buf, "%d\n", rbd_dev->major);
}
@@ -1831,7 +1849,7 @@
static ssize_t rbd_client_id_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct rbd_device *rbd_dev = dev_to_rbd(dev);
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
return sprintf(buf, "client%lld\n",
ceph_client_id(rbd_dev->rbd_client->client));
@@ -1840,7 +1858,7 @@
static ssize_t rbd_pool_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct rbd_device *rbd_dev = dev_to_rbd(dev);
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
return sprintf(buf, "%s\n", rbd_dev->pool_name);
}
@@ -1848,7 +1866,7 @@
static ssize_t rbd_name_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct rbd_device *rbd_dev = dev_to_rbd(dev);
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
return sprintf(buf, "%s\n", rbd_dev->obj);
}
@@ -1857,7 +1875,7 @@
struct device_attribute *attr,
char *buf)
{
- struct rbd_device *rbd_dev = dev_to_rbd(dev);
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
return sprintf(buf, "%s\n", rbd_dev->snap_name);
}
@@ -1867,7 +1885,7 @@
const char *buf,
size_t size)
{
- struct rbd_device *rbd_dev = dev_to_rbd(dev);
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
int rc;
int ret = size;
@@ -1932,7 +1950,7 @@
{
struct rbd_snap *snap = container_of(dev, struct rbd_snap, dev);
- return sprintf(buf, "%lld\n", (long long)snap->size);
+ return sprintf(buf, "%zd\n", snap->size);
}
static ssize_t rbd_snap_id_show(struct device *dev,
@@ -1941,7 +1959,7 @@
{
struct rbd_snap *snap = container_of(dev, struct rbd_snap, dev);
- return sprintf(buf, "%lld\n", (long long)snap->id);
+ return sprintf(buf, "%llu\n", (unsigned long long) snap->id);
}
static DEVICE_ATTR(snap_size, S_IRUGO, rbd_snap_size_show, NULL);
@@ -2232,7 +2250,8 @@
/*
* Skips over white space at *buf, and updates *buf to point to the
* first found non-space character (if any). Returns the length of
- * the token (string of non-white space characters) found.
+ * the token (string of non-white space characters) found. Note
+ * that *buf must be terminated with '\0'.
*/
static inline size_t next_token(const char **buf)
{
@@ -2250,13 +2269,14 @@
/*
* Finds the next token in *buf, and if the provided token buffer is
* big enough, copies the found token into it. The result, if
- * copied, is guaranteed to be terminated with '\0'.
+ * copied, is guaranteed to be terminated with '\0'. Note that *buf
+ * must be terminated with '\0' on entry.
*
* Returns the length of the token found (not including the '\0').
* Return value will be 0 if no token is found, and it will be >=
* token_size if the token would not fit.
*
- * The *buf pointer will be updated point beyond the end of the
+ * The *buf pointer will be updated to point beyond the end of the
* found token. Note that this occurs even if the token buffer is
* too small to hold it.
*/
@@ -2456,8 +2476,7 @@
static void rbd_dev_release(struct device *dev)
{
- struct rbd_device *rbd_dev =
- container_of(dev, struct rbd_device, dev);
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
if (rbd_dev->watch_request) {
struct ceph_client *client = rbd_dev->rbd_client->client;
@@ -2520,7 +2539,7 @@
const char *buf,
size_t count)
{
- struct rbd_device *rbd_dev = dev_to_rbd(dev);
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
int ret;
char *name = kmalloc(count + 1, GFP_KERNEL);
if (!name)