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block: Factor bdrv_read_unthrottled() out of guess_disk_lchs() 

To prepare move of guess_disk_lchs() into hw/, where it poking
BlockDriverState member io_limits_enabled directly would be unclean.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Markus Armbruster 2012-06-29 17:34:29 +02:00 committed by Kevin Wolf
parent bb494a505e
commit 07d27a442e
2 changed files with 19 additions and 7 deletions
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24
block.c
View File

@ -1639,6 +1639,20 @@ int bdrv_read(BlockDriverState *bs, int64_t sector_num,
return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false); return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false);
} }
/* Just like bdrv_read(), but with I/O throttling temporarily disabled */
int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
bool enabled;
int ret;
enabled = bs->io_limits_enabled;
bs->io_limits_enabled = false;
ret = bdrv_read(bs, 0, buf, 1);
bs->io_limits_enabled = enabled;
return ret;
}
#define BITS_PER_LONG (sizeof(unsigned long) * 8) #define BITS_PER_LONG (sizeof(unsigned long) * 8)
static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num, static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
@ -2136,11 +2150,10 @@ static int guess_disk_lchs(BlockDriverState *bs,
int *pcylinders, int *pheads, int *psectors) int *pcylinders, int *pheads, int *psectors)
{ {
uint8_t buf[BDRV_SECTOR_SIZE]; uint8_t buf[BDRV_SECTOR_SIZE];
int ret, i, heads, sectors, cylinders; int i, heads, sectors, cylinders;
struct partition *p; struct partition *p;
uint32_t nr_sects; uint32_t nr_sects;
uint64_t nb_sectors; uint64_t nb_sectors;
bool enabled;
bdrv_get_geometry(bs, &nb_sectors); bdrv_get_geometry(bs, &nb_sectors);
@ -2149,12 +2162,9 @@ static int guess_disk_lchs(BlockDriverState *bs,
* but also in async I/O mode. So the I/O throttling function has to * but also in async I/O mode. So the I/O throttling function has to
* be disabled temporarily here, not permanently. * be disabled temporarily here, not permanently.
*/ */
enabled = bs->io_limits_enabled; if (bdrv_read_unthrottled(bs, 0, buf, 1) < 0) {
bs->io_limits_enabled = false;
ret = bdrv_read(bs, 0, buf, 1);
bs->io_limits_enabled = enabled;
if (ret < 0)
return -1; return -1;
}
/* test msdos magic */ /* test msdos magic */
if (buf[510] != 0x55 || buf[511] != 0xaa) if (buf[510] != 0x55 || buf[511] != 0xaa)
return -1; return -1;

2
block.h
View File

@ -142,6 +142,8 @@ bool bdrv_dev_is_tray_open(BlockDriverState *bs);
bool bdrv_dev_is_medium_locked(BlockDriverState *bs); bool bdrv_dev_is_medium_locked(BlockDriverState *bs);
int bdrv_read(BlockDriverState *bs, int64_t sector_num, int bdrv_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors); uint8_t *buf, int nb_sectors);
int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors);
int bdrv_write(BlockDriverState *bs, int64_t sector_num, int bdrv_write(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors); const uint8_t *buf, int nb_sectors);
int bdrv_pread(BlockDriverState *bs, int64_t offset, int bdrv_pread(BlockDriverState *bs, int64_t offset,