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[Qemu-devel] [PATCH 3/3] block: get max_transfer limit for char (scsi-ge
From: |
Eric Farman |
Subject: |
[Qemu-devel] [PATCH 3/3] block: get max_transfer limit for char (scsi-generic) devices |
Date: |
Mon, 16 Jan 2017 22:12:01 +0100 |
Commit 6f607174 introduced a routine to get the maximum number
of bytes for a single I/O transfer for block devices, however
scsi generic devices are character devices, not block. Add
a condition for this, with slightly different logic because
the value is already in bytes, and need not be converted from
blocks as happens for block devices.
Signed-off-by: Eric Farman <address@hidden>
---
block/file-posix.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/block/file-posix.c b/block/file-posix.c
index 2115155..c0843c2 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -679,6 +679,13 @@ static void raw_refresh_limits(BlockDriverState *bs, Error
**errp)
if (ret > 0 && ret <= BDRV_REQUEST_MAX_SECTORS) {
bs->bl.max_transfer = pow2floor(ret << BDRV_SECTOR_BITS);
}
+ } else if (S_ISCHR(st.st_mode)) {
+ /* sg returns transfer length in bytes already */
+ int ret = hdev_get_max_transfer_length(bs, s->fd);
+ if (ret > 0 &&
+ (ret >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS) {
+ bs->bl.max_transfer = pow2floor(ret);
+ }
}
}
--
2.8.4