On Mon, Oct 31, 2016 at 1:23 PM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote:
> On Mon, Oct 31, 2016 at 12:43:09PM -0400, Rob Clark wrote:
>> From: Rob Clark <robclark@xxxxxxxxxxxxxxx>
>>
>> Rather than cut/pasting these couple ioctl wrappers everywhere, just
>> stuff them as static-inline into a header.
>>
>> This is probably mostly used from mesa, but some drivers, test apps, etc
>> may also want to use it from libdrm.
>>
>> v2: handle EINTR, add sync_accumulate() based on #dri-devel discussion,
>> etc
>>
>> Signed-off-by: Rob Clark <robclark@xxxxxxxxxxxxxxx>
>> ---
>> Makefile.sources | 1 +
>> libsync.h | 145 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 146 insertions(+)
>> create mode 100644 libsync.h
>>
>> diff --git a/Makefile.sources b/Makefile.sources
>> index a57036a..10aa1d0 100644
>> --- a/Makefile.sources
>> +++ b/Makefile.sources
>> @@ -13,6 +13,7 @@ LIBDRM_FILES := \
>> util_math.h
>>
>> LIBDRM_H_FILES := \
>> + libsync.h \
>> xf86drm.h \
>> xf86drmMode.h
>>
>> diff --git a/libsync.h b/libsync.h
>> new file mode 100644
>> index 0000000..2f9aafb
>> --- /dev/null
>> +++ b/libsync.h
>> @@ -0,0 +1,145 @@
>> +/*
>> + * sync abstraction
>> + * Copyright 2015-2016 Collabora Ltd.
>> + *
>> + * Based on the implementation from the Android Open Source Project,
>> + *
>> + * Copyright 2012 Google, Inc
>> + *
>> + * 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.
>> + */
>> +
>> +#ifndef _LIBSYNC_H
>> +#define _LIBSYNC_H
>> +
>> +#include <assert.h>
>> +#include <errno.h>
>> +#include <stdint.h>
>> +#include <string.h>
>> +#include <sys/ioctl.h>
>> +#include <sys/poll.h>
>> +#include <unistd.h>
>> +
>> +#if defined(__cplusplus)
>> +extern "C" {
>> +#endif
>> +
>> +/* duplicated from linux/sync_file.h to avoid build-time dependency
>> + * on new headers
>> + */
>> +struct sync_merge_data {
>> + char name[32];
>> + int32_t fd2;
>> + int32_t fence;
>> + uint32_t flags;
>> + uint32_t pad;
>> +};
>> +#define SYNC_IOC_MAGIC '>'
>> +#define SYNC_IOC_MERGE _IOWR(SYNC_IOC_MAGIC, 3, struct sync_merge_data)
>> +
>> +
>> +
>> +static inline int sync_wait(int fd, int timeout)
>> +{
>> + struct pollfd fds = {0};
>
> Would have thought you would have gone with fds = { fd, POLLIN }; :)
I'm a bit shakey on what compilers other than gcc would complain
about, so I was actually thinking about going the memset() route to be
super-pedantic..
I do prefer designated initializers but I seem to remember c++ being
unhappy about that. Not super huge big fan of undesignated
(anonymous?) initializers, but I guess it is probably syscall abi and
not the sort of thing where struct element order could change.. meh?
>> + int ret;
>> +
>> + fds.fd = fd;
>> + fds.events = POLLIN;
>> +
>> + do {
>> + ret = poll(&fds, 1, timeout);
>> + if (ret > 0) {
>> + if (fds.revents & (POLLERR | POLLNVAL)) {
>> + errno = EINVAL;
>> + return -1;
>> + }
>> + return 0;
>> + } else if (ret == 0) {
>> + errno = ETIME;
>> + return -1;
>> + }
>> + } while (ret == -1 && (errno == EINTR || errno == EAGAIN));
>> +
>> + return ret;
>> +}
>> +
>> +static inline int sync_merge(const char *name, int fd1, int fd2)
>> +{
>> + struct sync_merge_data data = {0};
>> + int ret;
>> +
>> + data.fd2 = fd2;
>> + strncpy(data.name, name, sizeof(data.name));
>> +
>> + do {
>> + ret = ioctl(fd1, SYNC_IOC_MERGE, &data);
>> + } while (ret == -1 && (errno == EINTR || errno == EAGAIN));
>> +
>> + if (ret < 0)
>> + return ret;
>> +
>> + return data.fence;
>> +}
>> +
>> +/* accumulate fd2 into fd1. If *fd1 is not a valid fd then dup fd2,
>> + * otherwise sync_merge() and close the old *fd1. This can be used
>> + * to implement the pattern:
>> + *
>> + * init()
>> + * {
>> + * batch.fence_fd = 1;
>
> -1
oh whoops, thx, fixed up locally
BR,
-R
>> + * }
>> + *
>> + * // does *NOT* take ownership of fd
>> + * server_sync(int fd)
>> + * {
>> + * if (sync_accumulate("foo", &batch.fence_fd, fd)) {
>> + * ... error ...
>> + * }
>> + * }
>> + */
>> +static inline int sync_accumulate(const char *name, int *fd1, int fd2)
>> +{
>> + int ret;
>> +
>> + assert(fd2 >= 0);
>> +
>> + if (*fd1 < 0) {
>> + *fd1 = dup(fd2);
>> + return 0;
>> + }
>> +
>> + ret = sync_merge(name, *fd1, fd2);
>> + if (ret < 0) {
>> + /* leave *fd1 as it is */
>> + return ret;
>> + }
>> +
>> + close(*fd1);
>> + *fd1 = ret;
>> +
>> + return 0;
>> +}
>
> Lgtm, matches how we want to use it.
> Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> -Chris
>
> --
> Chris Wilson, Intel Open Source Technology Centre
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