[PATCH v2 02/10] kvm tools: Remove the non-iov interface from disk image ops

Sasha Levin
2011-11-01T16:08:09Z

tools/kvm/disk/core.c | 48 ++++++----------------------------
tools/kvm/disk/qcow.c | 47 +++++++++++++++++++++++++++++++--
tools/kvm/disk/raw.c | 50 +++++++++++++++++++++---------------
tools/kvm/include/kvm/disk-image.h | 26 +++++++-----------
4 files changed, 91 insertions(+), 80 deletions(-)

diff --git a/tools/kvm/disk/core.c b/tools/kvm/disk/core.c
index 20e1990..78495cc 100644
--- a/tools/kvm/disk/core.c
+++ b/tools/kvm/disk/core.c
@@ -134,36 +134,19 @@ void disk_image__close_all(struct disk_image **disks, int count)
ssize_t disk_image__read(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount)
{
ssize_t total = 0;
- ssize_t nr;

if (debug_iodelay)
msleep(debug_iodelay);

- if (disk->ops->read_sector_iov) {
- /*
- * Try mulitple buffer based operation first
- */
- total = disk->ops->read_sector_iov(disk, sector, iov, iovcount);
+ if (disk->ops->read_sector) {
+ total = disk->ops->read_sector(disk, sector, iov, iovcount);
if (total < 0) {
pr_info("disk_image__read error: total=%ld\n", (long)total);
return -1;
}
- } else if (disk->ops->read_sector) {
- /*
- * Fallback to single buffer based operation
- */
- while (iovcount--) {
- nr = disk->ops->read_sector(disk, sector, iov->iov_base, iov->iov_len);
- if (nr != (ssize_t)iov->iov_len) {
- pr_info("disk_image__read error: nr = %ld iov_len=%ld\n", (long)nr, (long)iov->iov_len);
- return -1;
- }
- sector += iov->iov_len >> SECTOR_SHIFT;
- iov++;
- total += nr;
- }
- } else
+ } else {
die("No disk image operation for read\n");
+ }

return total;
}
@@ -175,37 +158,22 @@ ssize_t disk_image__read(struct disk_image *disk, u64 sector, const struct iovec
ssize_t disk_image__write(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount)
{
ssize_t total = 0;
- ssize_t nr;

if (debug_iodelay)
msleep(debug_iodelay);

- if (disk->ops->write_sector_iov) {
+ if (disk->ops->write_sector) {
/*
* Try writev based operation first
*/
- total = disk->ops->write_sector_iov(disk, sector, iov, iovcount);
+ total = disk->ops->write_sector(disk, sector, iov, iovcount);
if (total < 0) {
pr_info("disk_image__write error: total=%ld\n", (long)total);
return -1;
}
- } else if (disk->ops->write_sector) {
- /*
- * Fallback to single buffer based operation
- */
- while (iovcount--) {
- nr = disk->ops->write_sector(disk, sector, iov->iov_base, iov->iov_len);
- if (nr != (ssize_t)iov->iov_len) {
- pr_info("disk_image__write error: nr=%ld iov_len=%ld\n", (long)nr, (long)iov->iov_len);
- return -1;
- }
-
- sector += iov->iov_len >> SECTOR_SHIFT;
- iov++;
- total += nr;
- }
- } else
+ } else {
die("No disk image operation for read\n");
+ }

return total;
}
diff --git a/tools/kvm/disk/qcow.c b/tools/kvm/disk/qcow.c
index bdf6bd8..288782e 100644
--- a/tools/kvm/disk/qcow.c
+++ b/tools/kvm/disk/qcow.c
@@ -452,7 +452,7 @@ out_error:
return -1;
}

-static ssize_t qcow_read_sector(struct disk_image *disk, u64 sector,
+static ssize_t qcow_read_sector_single(struct disk_image *disk, u64 sector,
void *dst, u32 dst_len)
{
struct qcow *q = disk->priv;
@@ -488,6 +488,26 @@ static ssize_t qcow_read_sector(struct disk_image *disk, u64 sector,
return dst_len;
}

+static ssize_t qcow_read_sector(struct disk_image *disk, u64 sector,
+ const struct iovec *iov, int iovcount)
+{
+ ssize_t nr, total = 0;
+
+ while (iovcount--) {
+ nr = qcow_read_sector_single(disk, sector, iov->iov_base, iov->iov_len);
+ if (nr != (ssize_t)iov->iov_len) {
+ pr_info("qcow_read_sector error: nr=%ld iov_len=%ld\n", (long)nr, (long)iov->iov_len);
+ return -1;
+ }
+
+ sector += iov->iov_len >> SECTOR_SHIFT;
+ iov++;
+ total += nr;
+ }
+
+ return total;
+}
+
static inline u64 file_size(int fd)
{
struct stat st;
@@ -867,7 +887,7 @@ error:
return -1;
}

-static ssize_t qcow_write_sector(struct disk_image *disk, u64 sector, void *src, u32 src_len)
+static ssize_t qcow_write_sector_single(struct disk_image *disk, u64 sector, void *src, u32 src_len)
{
struct qcow *q = disk->priv;
struct qcow_header *header = q->header;
@@ -896,7 +916,28 @@ static ssize_t qcow_write_sector(struct disk_image *disk, u64 sector, void *src,
return nr_written;
}

-static ssize_t qcow_nowrite_sector(struct disk_image *disk, u64 sector, void *src, u32 src_len)
+static ssize_t qcow_write_sector(struct disk_image *disk, u64 sector,
+ const struct iovec *iov, int iovcount)
+{
+ ssize_t nr, total = 0;
+
+ while (iovcount--) {
+ nr = qcow_write_sector_single(disk, sector, iov->iov_base, iov->iov_len);
+ if (nr != (ssize_t)iov->iov_len) {
+ pr_info("qcow_write_sector error: nr=%ld iov_len=%ld\n", (long)nr, (long)iov->iov_len);
+ return -1;
+ }
+
+ sector += iov->iov_len >> SECTOR_SHIFT;
+ iov++;
+ total += nr;
+ }
+
+ return total;
+}
+
+static ssize_t qcow_nowrite_sector(struct disk_image *disk, u64 sector,
+ const struct iovec *iov, int iovcount)
{
/* I/O error */
pr_info("%s: no write support\n", __func__);
diff --git a/tools/kvm/disk/raw.c b/tools/kvm/disk/raw.c
index 66c52be..1c6a985 100644
--- a/tools/kvm/disk/raw.c
+++ b/tools/kvm/disk/raw.c
@@ -1,41 +1,49 @@
#include "kvm/disk-image.h"

-ssize_t raw_image__read_sector_iov(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount)
+ssize_t raw_image__read_sector(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount)
{
u64 offset = sector << SECTOR_SHIFT;

return preadv_in_full(disk->fd, iov, iovcount, offset);
}

-ssize_t raw_image__write_sector_iov(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount)
+ssize_t raw_image__write_sector(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount)
{
u64 offset = sector << SECTOR_SHIFT;

return pwritev_in_full(disk->fd, iov, iovcount, offset);
}

-ssize_t raw_image__read_sector(struct disk_image *disk, u64 sector, void *dst, u32 dst_len)
+ssize_t raw_image__read_sector_mmap(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount)
{
u64 offset = sector << SECTOR_SHIFT;
+ ssize_t nr, total = 0;

- if (offset + dst_len > disk->size)
- return -1;
+ while (iovcount--) {
+ memcpy(iov->iov_base, disk->priv + offset, iov->iov_len);

- memcpy(dst, disk->priv + offset, dst_len);
+ sector += iov->iov_len >> SECTOR_SHIFT;
+ iov++;
+ total += nr;
+ }

- return dst_len;
+ return total;
}

-ssize_t raw_image__write_sector(struct disk_image *disk, u64 sector, void *src, u32 src_len)
+ssize_t raw_image__write_sector_mmap(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount)
{
u64 offset = sector << SECTOR_SHIFT;
+ ssize_t nr, total = 0;

- if (offset + src_len > disk->size)
- return -1;
+ while (iovcount--) {
+ memcpy(disk->priv + offset, iov->iov_base, iov->iov_len);

- memcpy(disk->priv + offset, src, src_len);
+ sector += iov->iov_len >> SECTOR_SHIFT;
+ iov++;
+ total += nr;
+ }

- return src_len;
+ return total;
}

int raw_image__close(struct disk_image *disk)
@@ -51,17 +59,17 @@ int raw_image__close(struct disk_image *disk)
/*
* multiple buffer based disk image operations
*/
-static struct disk_image_operations raw_image_iov_ops = {
- .read_sector_iov = raw_image__read_sector_iov,
- .write_sector_iov = raw_image__write_sector_iov,
+static struct disk_image_operations raw_image_regular_ops = {
+ .read_sector = raw_image__read_sector,
+ .write_sector = raw_image__write_sector,
};

/*
- * single buffer based disk image operations
+ * mmap() based disk image operations
*/
-static struct disk_image_operations raw_image_ops = {
- .read_sector = raw_image__read_sector,
- .write_sector = raw_image__write_sector,
+static struct disk_image_operations raw_image_mmap_ops = {
+ .read_sector = raw_image__read_sector_mmap,
+ .write_sector = raw_image__write_sector_mmap,
.close = raw_image__close,
};

@@ -73,10 +81,10 @@ struct disk_image *raw_image__probe(int fd, struct stat *st, bool readonly)
* Use mmap's MAP_PRIVATE to implement non-persistent write
* FIXME: This does not work on 32-bit host.
*/
- return disk_image__new(fd, st->st_size, &raw_image_ops, DISK_IMAGE_MMAP);
+ return disk_image__new(fd, st->st_size, &raw_image_mmap_ops, DISK_IMAGE_MMAP);
else
/*
* Use read/write instead of mmap
*/
- return disk_image__new(fd, st->st_size, &raw_image_iov_ops, DISK_IMAGE_REGULAR);
+ return disk_image__new(fd, st->st_size, &raw_image_regular_ops, DISK_IMAGE_REGULAR);
}
diff --git a/tools/kvm/include/kvm/disk-image.h b/tools/kvm/include/kvm/disk-image.h
index 6acde53..6a6ae6f 100644
--- a/tools/kvm/include/kvm/disk-image.h
+++ b/tools/kvm/include/kvm/disk-image.h
@@ -31,18 +31,8 @@ enum {
struct disk_image;

struct disk_image_operations {
- /*
- * The following two are used for reading or writing with a single buffer.
- * The implentation can use readv/writev or memcpy.
- */
- ssize_t (*read_sector)(struct disk_image *disk, u64 sector, void *dst, u32 dst_len);
- ssize_t (*write_sector)(struct disk_image *disk, u64 sector, void *src, u32 src_len);
- /*
- * The following two are used for reading or writing with multiple buffers.
- * The implentation can use readv/writev or memcpy.
- */
- ssize_t (*read_sector_iov)(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount);
- ssize_t (*write_sector_iov)(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount);
+ ssize_t (*read_sector)(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount);
+ ssize_t (*write_sector)(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount);
int (*flush)(struct disk_image *disk);
int (*close)(struct disk_image *disk);
};
@@ -67,10 +57,14 @@ ssize_t disk_image__get_serial(struct disk_image *disk, void *buffer, ssize_t *l
struct disk_image *raw_image__probe(int fd, struct stat *st, bool readonly);
struct disk_image *blkdev__probe(const char *filename, struct stat *st);

-ssize_t raw_image__read_sector_iov(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount);
-ssize_t raw_image__write_sector_iov(struct disk_image *disk, u64 sector, const struct iovec *iov, int iovcount);
-ssize_t raw_image__read_sector(struct disk_image *disk, u64 sector, void *dst, u32 dst_len);
-ssize_t raw_image__write_sector(struct disk_image *disk, u64 sector, void *src, u32 src_len);
+ssize_t raw_image__read_sector(struct disk_image *disk, u64 sector,
+ const struct iovec *iov, int iovcount);
+ssize_t raw_image__write_sector(struct disk_image *disk, u64 sector,
+ const struct iovec *iov, int iovcount);
+ssize_t raw_image__read_sector_mmap(struct disk_image *disk, u64 sector,
+ const struct iovec *iov, int iovcount);
+ssize_t raw_image__write_sector_mmap(struct disk_image *disk, u64 sector,
+ const struct iovec *iov, int iovcount);
int raw_image__close(struct disk_image *disk);

#endif /* KVM__DISK_IMAGE_H */
--
1.7.7.1