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[PULL 14/28] scsi-generic: pass max_segments via max_iov field in BlockL
From: |
Paolo Bonzini |
Subject: |
[PULL 14/28] scsi-generic: pass max_segments via max_iov field in BlockLimits |
Date: |
Fri, 25 Jun 2021 16:18:08 +0200 |
I/O to a disk via read/write is not limited by the number of segments allowed
by the host adapter; the kernel can split requests if needed, and the limit
imposed by the host adapter can be very low (256k or so) to avoid that SG_IO
returns EINVAL if memory is heavily fragmented.
Since this value is only interesting for SG_IO-based I/O, do not include
it in the max_transfer and only take it into account when patching the
block limits VPD page in the scsi-generic device.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
block/file-posix.c | 3 +--
hw/scsi/scsi-generic.c | 6 ++++--
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/block/file-posix.c b/block/file-posix.c
index b8dc19ce1a..6db690baf2 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1237,8 +1237,7 @@ static void raw_refresh_limits(BlockDriverState *bs,
Error **errp)
ret = sg_get_max_segments(s->fd);
if (ret > 0) {
- bs->bl.max_transfer = MIN(bs->bl.max_transfer,
- ret * qemu_real_host_page_size);
+ bs->bl.max_iov = ret;
}
}
diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index 40e039864f..b6c4143dc7 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -179,10 +179,12 @@ static int scsi_handle_inquiry_reply(SCSIGenericReq *r,
SCSIDevice *s, int len)
(r->req.cmd.buf[1] & 0x01)) {
page = r->req.cmd.buf[2];
if (page == 0xb0) {
- uint32_t max_transfer =
- blk_get_max_transfer(s->conf.blk) / s->blocksize;
+ uint32_t max_transfer = blk_get_max_transfer(s->conf.blk);
+ uint32_t max_iov = blk_get_max_iov(s->conf.blk);
assert(max_transfer);
+ max_transfer = MIN_NON_ZERO(max_transfer, max_iov *
qemu_real_host_page_size)
+ / s->blocksize;
stl_be_p(&r->buf[8], max_transfer);
/* Also take care of the opt xfer len. */
stl_be_p(&r->buf[12],
--
2.31.1
- [PULL 04/28] meson: remove preadv from summary, (continued)
- [PULL 04/28] meson: remove preadv from summary, Paolo Bonzini, 2021/06/25
- [PULL 06/28] configure, meson: convert crypto detection to meson, Paolo Bonzini, 2021/06/25
- [PULL 09/28] configure, meson: convert libusb detection to meson, Paolo Bonzini, 2021/06/25
- [PULL 05/28] tests: remove QCRYPTO_HAVE_TLS_TEST_SUPPORT, Paolo Bonzini, 2021/06/25
- [PULL 08/28] configure, meson: convert pam detection to meson, Paolo Bonzini, 2021/06/25
- [PULL 10/28] configure, meson: convert libcacard detection to meson, Paolo Bonzini, 2021/06/25
- [PULL 11/28] configure, meson: convert libusbredir detection to meson, Paolo Bonzini, 2021/06/25
- [PULL 07/28] configure, meson: convert libtasn1 detection to meson, Paolo Bonzini, 2021/06/25
- [PULL 12/28] KVM: Fix dirty ring mmap incorrect size due to renaming accident, Paolo Bonzini, 2021/06/25
- [PULL 13/28] file-posix: fix max_iov for /dev/sg devices, Paolo Bonzini, 2021/06/25
- [PULL 14/28] scsi-generic: pass max_segments via max_iov field in BlockLimits,
Paolo Bonzini <=
- [PULL 16/28] block-backend: align max_transfer to request alignment, Paolo Bonzini, 2021/06/25
- [PULL 15/28] osdep: provide ROUND_DOWN macro, Paolo Bonzini, 2021/06/25
- [PULL 17/28] block: add max_hw_transfer to BlockLimits, Paolo Bonzini, 2021/06/25
- [PULL 18/28] file-posix: try BLKSECTGET on block devices too, do not round to power of 2, Paolo Bonzini, 2021/06/25
- [PULL 19/28] block: feature detection for host block support, Paolo Bonzini, 2021/06/25
- [PULL 21/28] block: try BSD disk size ioctls one after another, Paolo Bonzini, 2021/06/25
- [PULL 20/28] block: check for sys/disk.h, Paolo Bonzini, 2021/06/25
- [PULL 22/28] block: detect DKIOCGETBLOCKCOUNT/SIZE before use, Paolo Bonzini, 2021/06/25
- [PULL 23/28] file-posix: handle EINTR during ioctl, Paolo Bonzini, 2021/06/25