9:02 a.m.
On Sun, Feb 20, 2022 at 02:13:58PM +0200, Nir Soffer wrote:
Creating a new command requires lot of boilerplate that makes it
harder
to focus on the interesting code. Extract a helpers to create a command,
and the command slice buffer.
create_buffer is called only once, but the compiler is smart enough to
inline it, and adding it makes the code much simpler.
This change is a refactoring except fixing perror() message for calloc()
failure.
Signed-off-by: Nir Soffer <nsoffer(a)redhat.com>
---
copy/multi-thread-copying.c | 87 +++++++++++++++++++++++--------------
1 file changed, 54 insertions(+), 33 deletions(-)
if (exts.ptr[i].zero) {
/* The source is zero so we can proceed directly to skipping,
* fast zeroing, or writing zeroes at the destination.
*/
- command = calloc (1, sizeof *command);
- if (command == NULL) {
- perror ("malloc");
- exit (EXIT_FAILURE);
- }
- command->offset = exts.ptr[i].offset;
- command->slice.len = exts.ptr[i].length;
- command->slice.base = 0;
This assignment is dead code after calloc,...
- command->index = index;
+ command = create_command (exts.ptr[i].offset, exts.ptr[i].length,
+ true, index);
fill_dst_range_with_zeroes (command);
}
else /* data */ {
/* As the extent might be larger than permitted for a single
* command, we may have to split this into multiple read
* requests.
*/
while (exts.ptr[i].length > 0) {
len = exts.ptr[i].length;
if (len > request_size)
len = request_size;
- data = malloc (len);
- if (data == NULL) {
- perror ("malloc");
- exit (EXIT_FAILURE);
- }
- buffer = calloc (1, sizeof *buffer);
- if (buffer == NULL) {
- perror ("malloc");
- exit (EXIT_FAILURE);
- }
- buffer->data = data;
- buffer->refs = 1;
- command = calloc (1, sizeof *command);
- if (command == NULL) {
- perror ("malloc");
- exit (EXIT_FAILURE);
- }
- command->offset = exts.ptr[i].offset;
- command->slice.len = len;
- command->slice.base = 0;
...as was this,...
- command->slice.buffer = buffer;
- command->index = index;
+
+ command = create_command (exts.ptr[i].offset, len,
+ false, index);
wait_for_request_slots (index);
/* Begin the asynch read operation. */
src->ops->asynch_read (src, command,
(nbd_completion_callback) {
.callback = finished_read,
.user_data = command,
});
@@ -331,20 +305,67 @@ poll_both_ends (uintptr_t index)
else if ((fds[1].revents & POLLOUT) != 0)
dst->ops->asynch_notify_write (dst, index);
else if ((fds[1].revents & (POLLERR | POLLNVAL)) != 0) {
errno = ENOTCONN;
perror (dst->name);
exit (EXIT_FAILURE);
}
}
}
+/* Create a new buffer. */
+static struct buffer*
+create_buffer (size_t len)
+{
+ struct buffer *buffer;
+
+ buffer = calloc (1, sizeof *buffer);
+ if (buffer == NULL) {
+ perror ("calloc");
+ exit (EXIT_FAILURE);
+ }
+
+ buffer->data = malloc (len);
+ if (buffer->data == NULL) {
+ perror ("malloc");
+ exit (EXIT_FAILURE);
+ }
+
+ buffer->refs = 1;
+
+ return buffer;
+}
+
+/* Create a new command for read or zero. */
+static struct command *
+create_command (uint64_t offset, size_t len, bool zero, uintptr_t index)
+{
+ struct command *command;
+
+ command = calloc (1, sizeof *command);
+ if (command == NULL) {
+ perror ("calloc");
+ exit (EXIT_FAILURE);
+ }
+
+ command->offset = offset;
+ command->slice.len = len;
+ command->slice.base = 0;
...but keeping it here for the sake of refactoring is fine.
+
+ if (!zero)
+ command->slice.buffer = create_buffer (len);
+
+ command->index = index;
+
+ return command;
+}
ACK
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org