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99 lines
4.0 KiB
99 lines
4.0 KiB
From 884e6dfecc8b0f155015f0a25888300d8e1707f8 Mon Sep 17 00:00:00 2001
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From: Hanna Czenczek <hreitz@redhat.com>
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Date: Tue, 11 Apr 2023 19:34:15 +0200
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Subject: [PATCH 1/5] util/iov: Make qiov_slice() public
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RH-Author: Hanna Czenczek <hreitz@redhat.com>
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RH-MergeRequest: 291: block: Split padded I/O vectors exceeding IOV_MAX
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RH-Bugzilla: 2141964
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RH-Acked-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Commit: [1/5] 7f082982e49bacbcc21ca24e471b4399e64321a9
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We want to inline qemu_iovec_init_extended() in block/io.c for padding
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requests, and having access to qiov_slice() is useful for this. As a
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public function, it is renamed to qemu_iovec_slice().
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(We will need to count the number of I/O vector elements of a slice
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there, and then later process this slice. Without qiov_slice(), we
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would need to call qemu_iovec_subvec_niov(), and all further
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IOV-processing functions may need to skip prefixing elements to
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accomodate for a qiov_offset. Because qemu_iovec_subvec_niov()
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internally calls qiov_slice(), we can just have the block/io.c code call
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qiov_slice() itself, thus get the number of elements, and also create an
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iovec array with the superfluous prefixing elements stripped, so the
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following processing functions no longer need to skip them.)
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Reviewed-by: Eric Blake <eblake@redhat.com>
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Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
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Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
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Message-Id: <20230411173418.19549-2-hreitz@redhat.com>
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(cherry picked from commit 3d06cea8256d54a6b0238934c31012f7f17100f5)
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Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
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---
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include/qemu/iov.h | 3 +++
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util/iov.c | 14 +++++++-------
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2 files changed, 10 insertions(+), 7 deletions(-)
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diff --git a/include/qemu/iov.h b/include/qemu/iov.h
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index 9330746680..46fadfb27a 100644
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--- a/include/qemu/iov.h
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+++ b/include/qemu/iov.h
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@@ -229,6 +229,9 @@ int qemu_iovec_init_extended(
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void *tail_buf, size_t tail_len);
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void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source,
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size_t offset, size_t len);
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+struct iovec *qemu_iovec_slice(QEMUIOVector *qiov,
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+ size_t offset, size_t len,
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+ size_t *head, size_t *tail, int *niov);
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int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len);
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void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len);
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void qemu_iovec_concat(QEMUIOVector *dst,
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diff --git a/util/iov.c b/util/iov.c
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index 58c7b3eeee..3ccb530b16 100644
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--- a/util/iov.c
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+++ b/util/iov.c
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@@ -373,15 +373,15 @@ static struct iovec *iov_skip_offset(struct iovec *iov, size_t offset,
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}
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/*
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- * qiov_slice
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+ * qemu_iovec_slice
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*
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* Find subarray of iovec's, containing requested range. @head would
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* be offset in first iov (returned by the function), @tail would be
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* count of extra bytes in last iovec (returned iov + @niov - 1).
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*/
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-static struct iovec *qiov_slice(QEMUIOVector *qiov,
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- size_t offset, size_t len,
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- size_t *head, size_t *tail, int *niov)
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+struct iovec *qemu_iovec_slice(QEMUIOVector *qiov,
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+ size_t offset, size_t len,
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+ size_t *head, size_t *tail, int *niov)
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{
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struct iovec *iov, *end_iov;
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@@ -406,7 +406,7 @@ int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len)
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size_t head, tail;
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int niov;
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- qiov_slice(qiov, offset, len, &head, &tail, &niov);
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+ qemu_iovec_slice(qiov, offset, len, &head, &tail, &niov);
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return niov;
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}
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@@ -434,8 +434,8 @@ int qemu_iovec_init_extended(
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}
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if (mid_len) {
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- mid_iov = qiov_slice(mid_qiov, mid_offset, mid_len,
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- &mid_head, &mid_tail, &mid_niov);
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+ mid_iov = qemu_iovec_slice(mid_qiov, mid_offset, mid_len,
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+ &mid_head, &mid_tail, &mid_niov);
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}
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total_niov = !!head_len + mid_niov + !!tail_len;
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--
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2.39.3
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