[Qemu-devel] [PATCH FYI 30/46] migration: remove memory buffer based QEMUFile backend

["Daniel P. Berrange" <berrange@redhat.com>]

The qemu_bufopen() method is no longer used, so the memory
buffer based QEMUFile backend can be deleted entirely.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/migration/qemu-file.h |  15 --
 migration/Makefile.objs       |   2 +-
 migration/qemu-file-buf.c     | 462 ------------------------------------------
 3 files changed, 1 insertion(+), 478 deletions(-)
 delete mode 100644 migration/qemu-file-buf.c

diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
index ea49f33..c020b01 100644
--- a/include/migration/qemu-file.h
+++ b/include/migration/qemu-file.h
@@ -121,7 +121,6 @@ QEMUFile *qemu_fopen(const char *filename, const char *mode);
 QEMUFile *qemu_fdopen(int fd, const char *mode);
 QEMUFile *qemu_fopen_socket(int fd, const char *mode);
 QEMUFile *qemu_popen_cmd(const char *command, const char *mode);
-QEMUFile *qemu_bufopen(const char *mode, QEMUSizedBuffer *input);
 int qemu_get_fd(QEMUFile *f);
 int qemu_fclose(QEMUFile *f);
 int64_t qemu_ftell(QEMUFile *f);
@@ -136,20 +135,6 @@ void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size);
 bool qemu_file_mode_is_not_valid(const char *mode);
 bool qemu_file_is_writable(QEMUFile *f);
 
-QEMUSizedBuffer *qsb_create(const uint8_t *buffer, size_t len);
-void qsb_free(QEMUSizedBuffer *);
-size_t qsb_set_length(QEMUSizedBuffer *qsb, size_t length);
-size_t qsb_get_length(const QEMUSizedBuffer *qsb);
-ssize_t qsb_get_buffer(const QEMUSizedBuffer *, off_t start, size_t count,
-                       uint8_t *buf);
-ssize_t qsb_write_at(QEMUSizedBuffer *qsb, const uint8_t *buf,
-                     off_t pos, size_t count);
-
-
-/*
- * For use on files opened with qemu_bufopen
- */
-const QEMUSizedBuffer *qemu_buf_get(QEMUFile *f);
 
 static inline void qemu_put_ubyte(QEMUFile *f, unsigned int v)
 {
diff --git a/migration/Makefile.objs b/migration/Makefile.objs
index d929e96..ce1e3c7 100644
--- a/migration/Makefile.objs
+++ b/migration/Makefile.objs
@@ -1,6 +1,6 @@
 common-obj-y += migration.o tcp.o
 common-obj-y += vmstate.o
-common-obj-y += qemu-file.o qemu-file-buf.o qemu-file-unix.o qemu-file-stdio.o
+common-obj-y += qemu-file.o qemu-file-unix.o qemu-file-stdio.o
 common-obj-y += xbzrle.o
 
 common-obj-$(CONFIG_RDMA) += rdma.o
diff --git a/migration/qemu-file-buf.c b/migration/qemu-file-buf.c
deleted file mode 100644
index 556f5dc..0000000
--- a/migration/qemu-file-buf.c
+++ /dev/null
@@ -1,462 +0,0 @@
-/*
- * QEMU System Emulator
- *
- * Copyright (c) 2003-2008 Fabrice Bellard
- * Copyright (c) 2014 IBM Corp.
- *
- * Authors:
- *  Stefan Berger <stefanb@linux.vnet.ibm.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-#include "qemu-common.h"
-#include "qemu/error-report.h"
-#include "qemu/iov.h"
-#include "qemu/sockets.h"
-#include "qemu/coroutine.h"
-#include "migration/migration.h"
-#include "migration/qemu-file.h"
-#include "migration/qemu-file-internal.h"
-#include "trace.h"
-
-#define QSB_CHUNK_SIZE      (1 << 10)
-#define QSB_MAX_CHUNK_SIZE  (16 * QSB_CHUNK_SIZE)
-
-/**
- * Create a QEMUSizedBuffer
- * This type of buffer uses scatter-gather lists internally and
- * can grow to any size. Any data array in the scatter-gather list
- * can hold different amount of bytes.
- *
- * @buffer: Optional buffer to copy into the QSB
- * @len: size of initial buffer; if @buffer is given, buffer must
- *       hold at least len bytes
- *
- * Returns a pointer to a QEMUSizedBuffer or NULL on allocation failure
- */
-QEMUSizedBuffer *qsb_create(const uint8_t *buffer, size_t len)
-{
-    QEMUSizedBuffer *qsb;
-    size_t alloc_len, num_chunks, i, to_copy;
-    size_t chunk_size = (len > QSB_MAX_CHUNK_SIZE)
-                        ? QSB_MAX_CHUNK_SIZE
-                        : QSB_CHUNK_SIZE;
-
-    num_chunks = DIV_ROUND_UP(len ? len : QSB_CHUNK_SIZE, chunk_size);
-    alloc_len = num_chunks * chunk_size;
-
-    qsb = g_try_new0(QEMUSizedBuffer, 1);
-    if (!qsb) {
-        return NULL;
-    }
-
-    qsb->iov = g_try_new0(struct iovec, num_chunks);
-    if (!qsb->iov) {
-        g_free(qsb);
-        return NULL;
-    }
-
-    qsb->n_iov = num_chunks;
-
-    for (i = 0; i < num_chunks; i++) {
-        qsb->iov[i].iov_base = g_try_malloc0(chunk_size);
-        if (!qsb->iov[i].iov_base) {
-            /* qsb_free is safe since g_free can cope with NULL */
-            qsb_free(qsb);
-            return NULL;
-        }
-
-        qsb->iov[i].iov_len = chunk_size;
-        if (buffer) {
-            to_copy = (len - qsb->used) > chunk_size
-                      ? chunk_size : (len - qsb->used);
-            memcpy(qsb->iov[i].iov_base, &buffer[qsb->used], to_copy);
-            qsb->used += to_copy;
-        }
-    }
-
-    qsb->size = alloc_len;
-
-    return qsb;
-}
-
-/**
- * Free the QEMUSizedBuffer
- *
- * @qsb: The QEMUSizedBuffer to free
- */
-void qsb_free(QEMUSizedBuffer *qsb)
-{
-    size_t i;
-
-    if (!qsb) {
-        return;
-    }
-
-    for (i = 0; i < qsb->n_iov; i++) {
-        g_free(qsb->iov[i].iov_base);
-    }
-    g_free(qsb->iov);
-    g_free(qsb);
-}
-
-/**
- * Get the number of used bytes in the QEMUSizedBuffer
- *
- * @qsb: A QEMUSizedBuffer
- *
- * Returns the number of bytes currently used in this buffer
- */
-size_t qsb_get_length(const QEMUSizedBuffer *qsb)
-{
-    return qsb->used;
-}
-
-/**
- * Set the length of the buffer; the primary usage of this
- * function is to truncate the number of used bytes in the buffer.
- * The size will not be extended beyond the current number of
- * allocated bytes in the QEMUSizedBuffer.
- *
- * @qsb: A QEMUSizedBuffer
- * @new_len: The new length of bytes in the buffer
- *
- * Returns the number of bytes the buffer was truncated or extended
- * to.
- */
-size_t qsb_set_length(QEMUSizedBuffer *qsb, size_t new_len)
-{
-    if (new_len <= qsb->size) {
-        qsb->used = new_len;
-    } else {
-        qsb->used = qsb->size;
-    }
-    return qsb->used;
-}
-
-/**
- * Get the iovec that holds the data for a given position @pos.
- *
- * @qsb: A QEMUSizedBuffer
- * @pos: The index of a byte in the buffer
- * @d_off: Pointer to an offset that this function will indicate
- *         at what position within the returned iovec the byte
- *         is to be found
- *
- * Returns the index of the iovec that holds the byte at the given
- * index @pos in the byte stream; a negative number if the iovec
- * for the given position @pos does not exist.
- */
-static ssize_t qsb_get_iovec(const QEMUSizedBuffer *qsb,
-                             off_t pos, off_t *d_off)
-{
-    ssize_t i;
-    off_t curr = 0;
-
-    if (pos > qsb->used) {
-        return -1;
-    }
-
-    for (i = 0; i < qsb->n_iov; i++) {
-        if (curr + qsb->iov[i].iov_len > pos) {
-            *d_off = pos - curr;
-            return i;
-        }
-        curr += qsb->iov[i].iov_len;
-    }
-    return -1;
-}
-
-/*
- * Convert the QEMUSizedBuffer into a flat buffer.
- *
- * Note: If at all possible, try to avoid this function since it
- *       may unnecessarily copy memory around.
- *
- * @qsb: pointer to QEMUSizedBuffer
- * @start: offset to start at
- * @count: number of bytes to copy
- * @buf: a pointer to a buffer to write into (at least @count bytes)
- *
- * Returns the number of bytes copied into the output buffer
- */
-ssize_t qsb_get_buffer(const QEMUSizedBuffer *qsb, off_t start,
-                       size_t count, uint8_t *buffer)
-{
-    const struct iovec *iov;
-    size_t to_copy, all_copy;
-    ssize_t index;
-    off_t s_off;
-    off_t d_off = 0;
-    char *s;
-
-    if (start > qsb->used) {
-        return 0;
-    }
-
-    all_copy = qsb->used - start;
-    if (all_copy > count) {
-        all_copy = count;
-    } else {
-        count = all_copy;
-    }
-
-    index = qsb_get_iovec(qsb, start, &s_off);
-    if (index < 0) {
-        return 0;
-    }
-
-    while (all_copy > 0) {
-        iov = &qsb->iov[index];
-
-        s = iov->iov_base;
-
-        to_copy = iov->iov_len - s_off;
-        if (to_copy > all_copy) {
-            to_copy = all_copy;
-        }
-        memcpy(&buffer[d_off], &s[s_off], to_copy);
-
-        d_off += to_copy;
-        all_copy -= to_copy;
-
-        s_off = 0;
-        index++;
-    }
-
-    return count;
-}
-
-/**
- * Grow the QEMUSizedBuffer to the given size and allocate
- * memory for it.
- *
- * @qsb: A QEMUSizedBuffer
- * @new_size: The new size of the buffer
- *
- * Return:
- *    a negative error code in case of memory allocation failure
- * or
- *    the new size of the buffer. The returned size may be greater or equal
- *    to @new_size.
- */
-static ssize_t qsb_grow(QEMUSizedBuffer *qsb, size_t new_size)
-{
-    size_t needed_chunks, i;
-
-    if (qsb->size < new_size) {
-        struct iovec *new_iov;
-        size_t size_diff = new_size - qsb->size;
-        size_t chunk_size = (size_diff > QSB_MAX_CHUNK_SIZE)
-                             ? QSB_MAX_CHUNK_SIZE : QSB_CHUNK_SIZE;
-
-        needed_chunks = DIV_ROUND_UP(size_diff, chunk_size);
-
-        new_iov = g_try_new(struct iovec, qsb->n_iov + needed_chunks);
-        if (new_iov == NULL) {
-            return -ENOMEM;
-        }
-
-        /* Allocate new chunks as needed into new_iov */
-        for (i = qsb->n_iov; i < qsb->n_iov + needed_chunks; i++) {
-            new_iov[i].iov_base = g_try_malloc0(chunk_size);
-            new_iov[i].iov_len = chunk_size;
-            if (!new_iov[i].iov_base) {
-                size_t j;
-
-                /* Free previously allocated new chunks */
-                for (j = qsb->n_iov; j < i; j++) {
-                    g_free(new_iov[j].iov_base);
-                }
-                g_free(new_iov);
-
-                return -ENOMEM;
-            }
-        }
-
-        /*
-         * Now we can't get any allocation errors, copy over to new iov
-         * and switch.
-         */
-        for (i = 0; i < qsb->n_iov; i++) {
-            new_iov[i] = qsb->iov[i];
-        }
-
-        qsb->n_iov += needed_chunks;
-        g_free(qsb->iov);
-        qsb->iov = new_iov;
-        qsb->size += (needed_chunks * chunk_size);
-    }
-
-    return qsb->size;
-}
-
-/**
- * Write into the QEMUSizedBuffer at a given position and a given
- * number of bytes. This function will automatically grow the
- * QEMUSizedBuffer.
- *
- * @qsb: A QEMUSizedBuffer
- * @source: A byte array to copy data from
- * @pos: The position within the @qsb to write data to
- * @size: The number of bytes to copy into the @qsb
- *
- * Returns @size or a negative error code in case of memory allocation failure,
- *           or with an invalid 'pos'
- */
-ssize_t qsb_write_at(QEMUSizedBuffer *qsb, const uint8_t *source,
-                     off_t pos, size_t count)
-{
-    ssize_t rc = qsb_grow(qsb, pos + count);
-    size_t to_copy;
-    size_t all_copy = count;
-    const struct iovec *iov;
-    ssize_t index;
-    char *dest;
-    off_t d_off, s_off = 0;
-
-    if (rc < 0) {
-        return rc;
-    }
-
-    if (pos + count > qsb->used) {
-        qsb->used = pos + count;
-    }
-
-    index = qsb_get_iovec(qsb, pos, &d_off);
-    if (index < 0) {
-        return -EINVAL;
-    }
-
-    while (all_copy > 0) {
-        iov = &qsb->iov[index];
-
-        dest = iov->iov_base;
-
-        to_copy = iov->iov_len - d_off;
-        if (to_copy > all_copy) {
-            to_copy = all_copy;
-        }
-
-        memcpy(&dest[d_off], &source[s_off], to_copy);
-
-        s_off += to_copy;
-        all_copy -= to_copy;
-
-        d_off = 0;
-        index++;
-    }
-
-    return count;
-}
-
-typedef struct QEMUBuffer {
-    QEMUSizedBuffer *qsb;
-    QEMUFile *file;
-    bool qsb_allocated;
-} QEMUBuffer;
-
-static int buf_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
-{
-    QEMUBuffer *s = opaque;
-    ssize_t len = qsb_get_length(s->qsb) - pos;
-
-    if (len <= 0) {
-        return 0;
-    }
-
-    if (len > size) {
-        len = size;
-    }
-    return qsb_get_buffer(s->qsb, pos, len, buf);
-}
-
-static int buf_put_buffer(void *opaque, const uint8_t *buf,
-                          int64_t pos, int size)
-{
-    QEMUBuffer *s = opaque;
-
-    return qsb_write_at(s->qsb, buf, pos, size);
-}
-
-static int buf_close(void *opaque)
-{
-    QEMUBuffer *s = opaque;
-
-    if (s->qsb_allocated) {
-        qsb_free(s->qsb);
-    }
-
-    g_free(s);
-
-    return 0;
-}
-
-const QEMUSizedBuffer *qemu_buf_get(QEMUFile *f)
-{
-    QEMUBuffer *p;
-
-    qemu_fflush(f);
-
-    p = f->opaque;
-
-    return p->qsb;
-}
-
-static const QEMUFileOps buf_read_ops = {
-    .get_buffer = buf_get_buffer,
-    .close =      buf_close,
-};
-
-static const QEMUFileOps buf_write_ops = {
-    .put_buffer = buf_put_buffer,
-    .close =      buf_close,
-};
-
-QEMUFile *qemu_bufopen(const char *mode, QEMUSizedBuffer *input)
-{
-    QEMUBuffer *s;
-
-    if (mode == NULL || (mode[0] != 'r' && mode[0] != 'w') ||
-        mode[1] != '\0') {
-        error_report("qemu_bufopen: Argument validity check failed");
-        return NULL;
-    }
-
-    s = g_malloc0(sizeof(QEMUBuffer));
-    s->qsb = input;
-
-    if (s->qsb == NULL) {
-        s->qsb = qsb_create(NULL, 0);
-        s->qsb_allocated = true;
-    }
-    if (!s->qsb) {
-        g_free(s);
-        error_report("qemu_bufopen: qsb_create failed");
-        return NULL;
-    }
-
-
-    if (mode[0] == 'r') {
-        s->file = qemu_fopen_ops(s, &buf_read_ops);
-    } else {
-        s->file = qemu_fopen_ops(s, &buf_write_ops);
-    }
-    return s->file;
-}
-- 
2.4.3