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* 9pfs/coth.h: drop Doxygen format on v9fs_co_run_in_worker()Christian Schoenebeck2022-03-071-2/+2
| | | | | | | | | API doc comments in QEMU are supposed to be in kerneldoc format, so drop Doxygen format used on v9fs_co_run_in_worker() macro. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <a8fdf0290d1e40a68f5577f29aeae12298b70733.1646314856.git.qemu_oss@crudebyte.com>
* 9pfs: fix crash in v9fs_walk()Christian Schoenebeck2021-09-021-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | v9fs_walk() utilizes the v9fs_co_run_in_worker({...}) macro to run the supplied fs driver code block on a background worker thread. When either the 'Twalk' client request was interrupted or if the client requested fid for that 'Twalk' request caused a stat error then that fs driver code block was left by 'break' keyword, with the intention to return from worker thread back to main thread as well: v9fs_co_run_in_worker({ if (v9fs_request_cancelled(pdu)) { err = -EINTR; break; } err = s->ops->lstat(&s->ctx, &dpath, &fidst); if (err < 0) { err = -errno; break; } ... }); However that 'break;' statement also skipped the v9fs_co_run_in_worker() macro's final and mandatory /* re-enter back to qemu thread */ qemu_coroutine_yield(); call and thus caused the rest of v9fs_walk() to be continued being executed on the worker thread instead of main thread, eventually leading to a crash in the transport virtio transport driver. To fix this issue and to prevent the same error from happening again by other users of v9fs_co_run_in_worker() in future, auto wrap the supplied code block into its own do { } while (0); loop inside the 'v9fs_co_run_in_worker' macro definition. Full discussion and backtrace: https://lists.gnu.org/archive/html/qemu-devel/2021-08/msg05209.html https://lists.gnu.org/archive/html/qemu-devel/2021-09/msg00174.html Fixes: 8d6cb100731c4d28535adbf2a3c2d1f29be3fef4 Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Cc: qemu-stable@nongnu.org Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <E1mLTBg-0002Bh-2D@lizzy.crudebyte.com>
* 9pfs: clarify latency of v9fs_co_run_in_worker()Christian Schoenebeck2020-08-121-1/+11
| | | | | | | | | | | | As we just fixed a severe performance issue with Treaddir request handling, clarify this overall issue as a comment on v9fs_co_run_in_worker() with the intention to hopefully prevent such performance mistakes in future (and fixing other yet outstanding ones). Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <4d34d332e1aaa8a2cf8dc0b5da4fd7727f2a86e8.1596012787.git.qemu_oss@crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* 9pfs: add new function v9fs_co_readdir_many()Christian Schoenebeck2020-08-121-0/+3
| | | | | | | | | | | | | | | | | | | | The newly added function v9fs_co_readdir_many() retrieves multiple directory entries with a single fs driver request. It is intended to replace uses of v9fs_co_readdir(), the latter only retrieves a single directory entry per fs driver request instead. The reason for this planned replacement is that for every fs driver request the coroutine is dispatched from main I/O thread to a background I/O thread and eventually dispatched back to main I/O thread. Hopping between threads adds latency. So if a 9pfs Treaddir request reads a large amount of directory entries, this currently sums up to huge latencies of several hundred ms or even more. So using v9fs_co_readdir_many() instead of v9fs_co_readdir() will provide significant performance improvements. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Message-Id: <73dc827a12ef577ae7e644dcf34a5c0e443ab42f.1596012787.git.qemu_oss@crudebyte.com> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
* Include qemu/main-loop.h lessMarkus Armbruster2019-08-161-1/+0Star
| | | | | | | | | | | | | | | | | | | | In my "build everything" tree, changing qemu/main-loop.h triggers a recompile of some 5600 out of 6600 objects (not counting tests and objects that don't depend on qemu/osdep.h). It includes block/aio.h, which in turn includes qemu/event_notifier.h, qemu/notify.h, qemu/processor.h, qemu/qsp.h, qemu/queue.h, qemu/thread-posix.h, qemu/thread.h, qemu/timer.h, and a few more. Include qemu/main-loop.h only where it's needed. Touching it now recompiles only some 1700 objects. For block/aio.h and qemu/event_notifier.h, these numbers drop from 5600 to 2800. For the others, they shrink only slightly. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20190812052359.30071-21-armbru@redhat.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
* 9pfs: use coroutine_fn annotation in hw/9pfs/co*.[ch]Greg Kurz2016-10-171-46/+47
| | | | | | | | | All these functions use the v9fs_co_run_in_worker() macro, and thus always call qemu_coroutine_self() and qemu_coroutine_yield(). Let's mark them to make it obvious they execute in coroutine context. Signed-off-by: Greg Kurz <groug@kaod.org>
* 9pfs: fsdev: drop useless extern annotation for functionsGreg Kurz2016-10-171-47/+47
| | | | Signed-off-by: Greg Kurz <groug@kaod.org>
* Clean up ill-advised or unusual header guardsMarkus Armbruster2016-07-121-2/+2
| | | | | | | Cleaned up with scripts/clean-header-guards.pl. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net>
* 9p: switch back to readdir()Greg Kurz2016-06-061-2/+1Star
| | | | | | | | | | This patch changes the 9p code to use readdir() again instead of readdir_r(), which is deprecated in glibc 2.24. All the locking was put in place by a previous patch. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
* 9p/fsdev: remove obsolete references to virtioGreg Kurz2016-06-061-1/+2
| | | | | | | | | | Most of the 9p code is now virtio agnostic. This patch does a final cleanup: - drop references to Virtio from the header comments - fix includes Also drop a couple of leading empty lines while here. Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
* 9p: drop unused declaration from coth.hGreg Kurz2016-05-181-1/+0Star
| | | | | | | | Commit "ebac1202c95a virtio-9p: use QEMU thread pool" dropped function v9fs_init_worker_threads. Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
* 9pfs: rename virtio-9p-coth.{c,h} to coth.{c,h}Wei Liu2016-01-081-0/+99
Those two files are not virtio specific. Rename them to use generic names. Fix includes in various C files. Change define guards and comments in header files. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>