[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH v3 06/22] iscsi: Advertise realistic limits to block
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PATCH v3 06/22] iscsi: Advertise realistic limits to block layer |
Date: |
Thu, 23 Jun 2016 16:37:10 -0600 |
The function sector_limits_lun2qemu() returns a value in units of
the block layer's 512-byte sector, and can be as large as
0x40000000, which is much larger than the block layer's inherent
limit of BDRV_REQUEST_MAX_SECTORS. The block layer already
handles '0' as a synonym to the inherent limit, and it is nicer
to return this value than it is to calculate an arbitrary
maximum, for two reasons: we want to ensure that the block layer
continues to special-case '0' as 'no limit beyond the inherent
limits'; and we want to be able to someday expand the block
layer to allow 64-bit limits, where auditing for uses of
BDRV_REQUEST_MAX_SECTORS will help us make sure we aren't
artificially constraining iscsi to old block layer limits.
Signed-off-by: Eric Blake <address@hidden>
Reviewed-by: Kevin Wolf <address@hidden>
Reviewed-by: Fam Zheng <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
---
v3: no change
v2: new patch
---
block/iscsi.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/block/iscsi.c b/block/iscsi.c
index 7e78ade..4290e41 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -1697,7 +1697,9 @@ static void iscsi_close(BlockDriverState *bs)
static int sector_limits_lun2qemu(int64_t sector, IscsiLun *iscsilun)
{
- return MIN(sector_lun2qemu(sector, iscsilun), INT_MAX / 2 + 1);
+ int limit = MIN(sector_lun2qemu(sector, iscsilun), INT_MAX / 2 + 1);
+
+ return limit < BDRV_REQUEST_MAX_SECTORS ? limit : 0;
}
static void iscsi_refresh_limits(BlockDriverState *bs, Error **errp)
--
2.5.5
- [Qemu-devel] [PATCH v3 00/22] Byte-based block limits, Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 04/22] nbd: Allow larger requests, Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 09/22] blkdebug: Set request_alignment during .bdrv_refresh_limits(), Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 08/22] block: Give nonzero result to blk_get_max_transfer_length(), Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 02/22] block: Document supported flags during bdrv_aligned_preadv(), Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 06/22] iscsi: Advertise realistic limits to block layer,
Eric Blake <=
- [Qemu-devel] [PATCH v3 05/22] nbd: Advertise realistic limits to block layer, Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 07/22] scsi: Advertise limits by blocksize, not 512, Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 01/22] block: Tighter assertions on bdrv_aligned_pwritev(), Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 13/22] block: Set request_alignment during .bdrv_refresh_limits(), Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 10/22] iscsi: Set request_alignment during .bdrv_refresh_limits(), Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 15/22] block: Switch transfer length bounds to byte-based, Eric Blake, 2016/06/23
- [Qemu-devel] [PATCH v3 17/22] block: Switch discard length bounds to byte-based, Eric Blake, 2016/06/23