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block: Move request_alignment into BlockLimit

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It makes more sense to have ALL block size limit constraints
in the same struct.  Improve the documentation while at it.

Simplify a couple of conditionals, now that we have audited and
documented that request_alignment is always non-zero.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Eric Blake 2016-06-23 16:37:24 -06:00 committed by Kevin Wolf
parent d9e0dfa246
commit a5b8dd2ce8
12 changed files with 39 additions and 35 deletions
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2
block.c
View File

@ -1016,7 +1016,7 @@ static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
assert(bdrv_opt_mem_align(bs) != 0);
assert(bdrv_min_mem_align(bs) != 0);
assert(is_power_of_2(bs->request_alignment) || bdrv_is_sg(bs));
assert(is_power_of_2(bs->bl.request_alignment));
qemu_opts_del(opts);
return 0;

2
block/blkdebug.c
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@ -726,7 +726,7 @@ static void blkdebug_refresh_limits(BlockDriverState *bs, Error **errp)
BDRVBlkdebugState *s = bs->opaque;
if (s->align) {
bs->request_alignment = s->align;
bs->bl.request_alignment = s->align;
}
}

2
block/bochs.c
View File

@ -190,7 +190,7 @@ fail:
static void bochs_refresh_limits(BlockDriverState *bs, Error **errp)
{
bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
}
static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)

2
block/cloop.c
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@ -200,7 +200,7 @@ fail:
static void cloop_refresh_limits(BlockDriverState *bs, Error **errp)
{
bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
}
static inline int cloop_read_block(BlockDriverState *bs, int block_num)

2
block/dmg.c
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@ -548,7 +548,7 @@ fail:
static void dmg_refresh_limits(BlockDriverState *bs, Error **errp)
{
bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
}
static inline int is_sector_in_chunk(BDRVDMGState* s,

14
block/io.c
View File

@ -90,7 +90,7 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
}
/* Default alignment based on whether driver has byte interface */
bs->request_alignment = drv->bdrv_co_preadv ? 1 : 512;
bs->bl.request_alignment = drv->bdrv_co_preadv ? 1 : 512;
/* Take some limits from the children as a default */
if (bs->file) {
@ -459,7 +459,7 @@ static int bdrv_get_cluster_size(BlockDriverState *bs)
ret = bdrv_get_info(bs, &bdi);
if (ret < 0 || bdi.cluster_size == 0) {
return bs->request_alignment;
return bs->bl.request_alignment;
} else {
return bdi.cluster_size;
}
@ -1068,7 +1068,7 @@ int coroutine_fn bdrv_co_preadv(BlockDriverState *bs,
BlockDriver *drv = bs->drv;
BdrvTrackedRequest req;
uint64_t align = bs->request_alignment;
uint64_t align = bs->bl.request_alignment;
uint8_t *head_buf = NULL;
uint8_t *tail_buf = NULL;
QEMUIOVector local_qiov;
@ -1164,8 +1164,8 @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
int tail = 0;
int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_pwrite_zeroes, INT_MAX);
int alignment = MAX(bs->bl.pwrite_zeroes_alignment ?: 1,
bs->request_alignment);
int alignment = MAX(bs->bl.pwrite_zeroes_alignment,
bs->bl.request_alignment);
assert(is_power_of_2(alignment));
head = offset & (alignment - 1);
@ -1324,7 +1324,7 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BlockDriverState *bs,
uint8_t *buf = NULL;
QEMUIOVector local_qiov;
struct iovec iov;
uint64_t align = bs->request_alignment;
uint64_t align = bs->bl.request_alignment;
unsigned int head_padding_bytes, tail_padding_bytes;
int ret = 0;
@ -1411,7 +1411,7 @@ int coroutine_fn bdrv_co_pwritev(BlockDriverState *bs,
BdrvRequestFlags flags)
{
BdrvTrackedRequest req;
uint64_t align = bs->request_alignment;
uint64_t align = bs->bl.request_alignment;
uint8_t *head_buf = NULL;
uint8_t *tail_buf = NULL;
QEMUIOVector local_qiov;

2
block/iscsi.c
View File

@ -1705,7 +1705,7 @@ static void iscsi_refresh_limits(BlockDriverState *bs, Error **errp)
IscsiLun *iscsilun = bs->opaque;
uint64_t max_xfer_len = iscsilun->use_16_for_rw ? 0xffffffff : 0xffff;
bs->request_alignment = iscsilun->block_size;
bs->bl.request_alignment = iscsilun->block_size;
if (iscsilun->bl.max_xfer_len) {
max_xfer_len = MIN(max_xfer_len, iscsilun->bl.max_xfer_len);

2
block/qcow2.c
View File

@ -1201,7 +1201,7 @@ static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp)
if (bs->encrypted) {
/* Encryption works on a sector granularity */
bs->request_alignment = BDRV_SECTOR_SIZE;
bs->bl.request_alignment = BDRV_SECTOR_SIZE;
}
bs->bl.pwrite_zeroes_alignment = s->cluster_size;
}

16
block/raw-posix.c
View File

@ -302,22 +302,22 @@ static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp)
/* For SCSI generic devices the alignment is not really used.
With buffered I/O, we don't have any restrictions. */
if (bdrv_is_sg(bs) || !s->needs_alignment) {
bs->request_alignment = 1;
bs->bl.request_alignment = 1;
s->buf_align = 1;
return;
}
bs->request_alignment = 0;
bs->bl.request_alignment = 0;
s->buf_align = 0;
/* Let's try to use the logical blocksize for the alignment. */
if (probe_logical_blocksize(fd, &bs->request_alignment) < 0) {
bs->request_alignment = 0;
if (probe_logical_blocksize(fd, &bs->bl.request_alignment) < 0) {
bs->bl.request_alignment = 0;
}
#ifdef CONFIG_XFS
if (s->is_xfs) {
struct dioattr da;
if (xfsctl(NULL, fd, XFS_IOC_DIOINFO, &da) >= 0) {
bs->request_alignment = da.d_miniosz;
bs->bl.request_alignment = da.d_miniosz;
/* The kernel returns wrong information for d_mem */
/* s->buf_align = da.d_mem; */
}
@ -337,19 +337,19 @@ static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp)
qemu_vfree(buf);
}
if (!bs->request_alignment) {
if (!bs->bl.request_alignment) {
size_t align;
buf = qemu_memalign(s->buf_align, max_align);
for (align = 512; align <= max_align; align <<= 1) {
if (raw_is_io_aligned(fd, buf, align)) {
bs->request_alignment = align;
bs->bl.request_alignment = align;
break;
}
}
qemu_vfree(buf);
}
if (!s->buf_align || !bs->request_alignment) {
if (!s->buf_align || !bs->bl.request_alignment) {
error_setg(errp, "Could not find working O_DIRECT alignment. "
"Try cache.direct=off.");
}

6
block/raw-win32.c
View File

@ -230,14 +230,14 @@ static void raw_probe_alignment(BlockDriverState *bs, Error **errp)
BOOL status;
if (s->type == FTYPE_CD) {
bs->request_alignment = 2048;
bs->bl.request_alignment = 2048;
return;
}
if (s->type == FTYPE_HARDDISK) {
status = DeviceIoControl(s->hfile, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX,
NULL, 0, &dg, sizeof(dg), &count, NULL);
if (status != 0) {
bs->request_alignment = dg.Geometry.BytesPerSector;
bs->bl.request_alignment = dg.Geometry.BytesPerSector;
return;
}
/* try GetDiskFreeSpace too */
@ -247,7 +247,7 @@ static void raw_probe_alignment(BlockDriverState *bs, Error **errp)
GetDiskFreeSpace(s->drive_path, &sectorsPerCluster,
&dg.Geometry.BytesPerSector,
&freeClusters, &totalClusters);
bs->request_alignment = dg.Geometry.BytesPerSector;
bs->bl.request_alignment = dg.Geometry.BytesPerSector;
}
}

2
block/vvfat.c
View File

@ -1210,7 +1210,7 @@ fail:
static void vvfat_refresh_limits(BlockDriverState *bs, Error **errp)
{
bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
}
static inline void vvfat_close_current_file(BDRVVVFATState *s)

22
include/block/block_int.h
View File

@ -324,6 +324,12 @@ struct BlockDriver {
};
typedef struct BlockLimits {
/* Alignment requirement, in bytes, for offset/length of I/O
* requests. Must be a power of 2 less than INT_MAX; defaults to
* 1 for drivers with modern byte interfaces, and to 512
* otherwise. */
uint32_t request_alignment;
/* maximum number of bytes that can be discarded at once (since it
* is signed, it must be < 2G, if set), should be multiple of
* pdiscard_alignment, but need not be power of 2. May be 0 if no
@ -332,8 +338,8 @@ typedef struct BlockLimits {
/* optimal alignment for discard requests in bytes, must be power
* of 2, less than max_pdiscard if that is set, and multiple of
* bs->request_alignment. May be 0 if bs->request_alignment is
* good enough */
* bl.request_alignment. May be 0 if bl.request_alignment is good
* enough */
uint32_t pdiscard_alignment;
/* maximum number of bytes that can zeroized at once (since it is
@ -343,12 +349,12 @@ typedef struct BlockLimits {
/* optimal alignment for write zeroes requests in bytes, must be
* power of 2, less than max_pwrite_zeroes if that is set, and
* multiple of bs->request_alignment. May be 0 if
* bs->request_alignment is good enough */
* multiple of bl.request_alignment. May be 0 if
* bl.request_alignment is good enough */
uint32_t pwrite_zeroes_alignment;
/* optimal transfer length in bytes (must be power of 2, and
* multiple of bs->request_alignment), or 0 if no preferred size */
* multiple of bl.request_alignment), or 0 if no preferred size */
uint32_t opt_transfer;
/* maximal transfer length in bytes (need not be power of 2, but
@ -356,10 +362,10 @@ typedef struct BlockLimits {
* For now, anything larger than INT_MAX is clamped down. */
uint32_t max_transfer;
/* memory alignment so that no bounce buffer is needed */
/* memory alignment, in bytes so that no bounce buffer is needed */
size_t min_mem_alignment;
/* memory alignment for bounce buffer */
/* memory alignment, in bytes, for bounce buffer */
size_t opt_mem_alignment;
/* maximum number of iovec elements */
@ -465,8 +471,6 @@ struct BlockDriverState {
/* I/O Limits */
BlockLimits bl;
/* Alignment requirement for offset/length of I/O requests */
unsigned int request_alignment;
/* Flags honored during pwrite (so far: BDRV_REQ_FUA) */
unsigned int supported_write_flags;
/* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA,