On 03.06.21 15:37, Paolo Bonzini wrote:
Even though it was only called for devices that have bs->sg set (which
must be character devices),
sg_get_max_segments looked at /sys/dev/block which only works for
block devices.
On Linux the sg driver has its own way to provide the maximum number of
iovecs in a scatter/gather list.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
block/file-posix.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/block/file-posix.c b/block/file-posix.c
index f37dfc10b3..58db526cc2 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1180,6 +1180,17 @@ static int sg_get_max_segments(int fd)
goto out;
}
+ if (S_ISCHR(st->st_mode)) {
+ if (ioctl(fd, SG_GET_SG_TABLESIZE, &ret) == 0) {
+ return ret;
+ }
+ return -EIO;
+ }
+
+ if (!S_ISBLK(st->st_mode)) {
+ return -ENOTSUP;
+ }
+
With %s/->/./:
Reviewed-by: Max Reitz <mre...@redhat.com>
(To answer Vladimir’s question, I don’t believe the condition should be
bs->sg, because bs->sg == true is a given for this function anyway.
Therefore, there’s no need to check whether the char device is an SG
device.)
