Blame SOURCES/kvm-raw-posix-Fetch-max-sectors-for-host-block-device.patch

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From 52288902dd647cbcfa470a11867163a6e5983297 Mon Sep 17 00:00:00 2001
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From: Fam Zheng <famz@redhat.com>
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Date: Mon, 11 Jul 2016 05:33:38 +0200
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Subject: [PATCH 5/7] raw-posix: Fetch max sectors for host block device
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RH-Author: Fam Zheng <famz@redhat.com>
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Message-id: <1468215219-30793-6-git-send-email-famz@redhat.com>
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Patchwork-id: 71109
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O-Subject: [RHEL-7.3 qemu-kvm PATCH 5/6] raw-posix: Fetch max sectors for host block device
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Bugzilla: 1318199
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: John Snow <jsnow@redhat.com>
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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This is sometimes a useful value we should count in.
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Signed-off-by: Fam Zheng <famz@redhat.com>
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Reviewed-by: Eric Blake <eblake@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit 6f6071745bd0366221f5a0160ed7d18d0e38b9f7)
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Signed-off-by: Fam Zheng <famz@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 block/raw-posix.c | 24 ++++++++++++++++++++++++
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 1 file changed, 24 insertions(+)
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diff --git a/block/raw-posix.c b/block/raw-posix.c
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index 92fcb6c..ed97bd4 100644
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--- a/block/raw-posix.c
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+++ b/block/raw-posix.c
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@@ -587,9 +587,33 @@ static void raw_reopen_abort(BDRVReopenState *state)
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     state->opaque = NULL;
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 }
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+static int hdev_get_max_transfer_length(int fd)
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+{
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+#ifdef BLKSECTGET
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+    int max_sectors = 0;
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+    if (ioctl(fd, BLKSECTGET, &max_sectors) == 0) {
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+        return max_sectors;
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+    } else {
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+        return -errno;
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+    }
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+#else
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+    return -ENOSYS;
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+#endif
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+}
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+
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 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
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 {
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     BDRVRawState *s = bs->opaque;
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+    struct stat st;
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+
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+    if (!fstat(s->fd, &st)) {
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+        if (S_ISBLK(st.st_mode)) {
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+            int ret = hdev_get_max_transfer_length(s->fd);
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+            if (ret >= 0) {
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+                bs->bl.max_transfer_length = ret;
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+            }
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+        }
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+    }
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     raw_probe_alignment(bs, s->fd, errp);
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     bs->bl.opt_mem_alignment = s->buf_align;
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-- 
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1.8.3.1
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