From 91c9803cb4dc5251abbb9af312c917dddfdd689e Mon Sep 17 00:00:00 2001
From: Bernd Schubert <bschubert@ddn.com>
Date: Tue, 15 Apr 2025 20:42:19 +0200
Subject: passthrough_hp: Add io-uring options

Signed-off-by: Bernd Schubert <bschubert@ddn.com>
---
 example/passthrough_hp.cc | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

(limited to 'example')

diff --git a/example/passthrough_hp.cc b/example/passthrough_hp.cc
index 8b5214c..b88c2c5 100644
--- a/example/passthrough_hp.cc
+++ b/example/passthrough_hp.cc
@@ -77,6 +77,9 @@ using namespace std;
 
 #define SFS_DEFAULT_THREADS "-1" // take libfuse value as default
 #define SFS_DEFAULT_CLONE_FD "0"
+#define SFS_DEFAULT_URING  "1"
+#define SFS_DEFAULT_URING_Q_DEPTH "0"
+#define SFS_DEFAULT_URING_ARGLEN    "0"
 
 /* We are re-using pointers to our `struct sfs_inode` and `struct
    sfs_dirp` elements as inodes and file handles. This means that we
@@ -155,6 +158,11 @@ struct Fs {
     bool nocache;
     size_t num_threads;
     bool clone_fd;
+    struct {
+        bool enable;
+        int queue_depth;
+    } uring;
+
     std::string fuse_mount_options;
     bool direct_io;
     bool passthrough;
@@ -1400,10 +1408,12 @@ static cxxopts::ParseResult parse_options(int argc, char **argv) {
         ("o", "Mount options (see mount.fuse(5) - only use if you know what "
               "you are doing)", cxxopts::value(mount_options))
         ("num-threads", "Number of libfuse worker threads",
-                        cxxopts::value<int>()->default_value(SFS_DEFAULT_THREADS))
+            cxxopts::value<int>()->default_value(SFS_DEFAULT_THREADS))
         ("clone-fd", "use separate fuse device fd for each thread")
-        ("direct-io", "enable fuse kernel internal direct-io");
-
+        ("direct-io", "enable fuse kernel internal direct-io")
+        ("uring", "use uring communication")
+        ("uring-q-depth", "io-uring queue depth",
+            cxxopts::value<int>()->default_value(SFS_DEFAULT_URING_Q_DEPTH));
     // FIXME: Find a better way to limit the try clause to just
     // opt_parser.parse() (cf. https://github.com/jarro2783/cxxopts/issues/146)
     auto options = parse_wrapper(opt_parser, argc, argv);
@@ -1435,6 +1445,10 @@ static cxxopts::ParseResult parse_options(int argc, char **argv) {
     fs.num_threads = options["num-threads"].as<int>();
     fs.clone_fd = options.count("clone-fd");
     fs.direct_io = options.count("direct-io");
+
+    fs.uring.enable = options.count("uring");
+    fs.uring.queue_depth = options["uring-q-depth"].as<int>();
+
     char* resolved_path = realpath(argv[1], NULL);
     if (resolved_path == NULL)
         warn("WARNING: realpath() failed with");
@@ -1518,7 +1532,14 @@ int main(int argc, char *argv[]) {
         fuse_opt_add_arg(&args, "-o") ||
         fuse_opt_add_arg(&args, fs.fuse_mount_options.c_str()) ||
         (fs.debug_fuse && fuse_opt_add_arg(&args, "-odebug")))
-        errx(3, "ERROR: Out of memory");
+        errx(3, "ERROR: Out of memory adding arguments");
+
+    if (fs.uring.enable) {
+        if (fuse_opt_add_arg(&args, "-oio_uring") ||
+            fuse_opt_add_arg(&args, ("-oio_uring_q_depth=" +
+            std::to_string(fs.uring.queue_depth)).c_str()))
+            errx(3, "ERROR: Out of memory adding io-uring arguments");
+    }
 
     ret = -1;
     fuse_lowlevel_ops sfs_oper {};
-- 
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