Fix warning when configuring /recompress. Actually write global recompression configuration

man/zram-generator.conf.md

@@ -79,8 +79,8 @@ Devices with the final size of *0* will be discarded.
   If unset, none will be configured and the kernel's default will be used.<br />
   If more than one is given, and recompression is enabled in the kernel, subsequent ones will be set as the recompression algorithms, with decreasing priority.
 
-  If a compression algorithm is suffixed with a parenthesised comma-separated list of parameters, those are given to `.../algorithm_params` (and `.../recompress`).
-  A parenthesised parameter list *without* a compression algorithm is set as the global recompression parameters.
+  If a compression algorithm is suffixed with a parenthesised comma-separated list of parameters, those are given to `.../algorithm_params`.
+  A parenthesised parameter list *without* a compression algorithm is written to `.../recompress`.
 
 * `writeback-device`=
 

src/setup.rs

@@ -35,44 +35,25 @@ pub fn run_device_setup(device: Option<Device>, device_name: &str) -> Result<()>
         .iter()
         .enumerate()
     {
-        let params = if params.is_empty() {
-            None
-        } else {
-            Some(params)
-        };
-        let (path, data, add_pathdata) = if prio == 0 {
-            (
-                device_sysfs_path.join("comp_algorithm"),
-                algo,
-                params.as_ref().map(|p| {
-                    (
-                        device_sysfs_path.join("algorithm_params"),
-                        format!("algo={} {}", algo, p),
-                    )
-                }),
-            )
+        let (path, data) = if prio == 0 {
+            (device_sysfs_path.join("comp_algorithm"), algo)
         } else {
             (
                 device_sysfs_path.join("recomp_algorithm"),
                 &format!("algo={} priority={}", algo, prio),
-                params.as_ref().map(|p| {
-                    (
-                        device_sysfs_path.join("recompress"),
-                        format!("{} priority={}", p, prio),
-                    )
-                }),
             )
         };
 
         match fs::write(&path, data) {
             Ok(_) => {
-                if let Some((add_path, add_data)) = add_pathdata {
-                    match fs::write(add_path, add_data) {
+                if !params.is_empty() {
+                    let add_data = format!("priority={} {}", prio, params);
+                    match fs::write(device_sysfs_path.join("algorithm_params"), &add_data) {
                         Ok(_) => {}
                         Err(err) => {
                             warn!(
                                 "Warning: algorithm {:?} supplemental data {:?} not written: {}",
-                                algo, data, err,
+                                algo, add_data, err,
                             );
                         }
                     }
@@ -98,6 +79,24 @@ pub fn run_device_setup(device: Option<Device>, device_name: &str) -> Result<()>
             })?,
         }
     }
+    if !device
+        .compression_algorithms
+        .recompression_global
+        .is_empty()
+    {
+        match fs::write(
+            device_sysfs_path.join("recompress"),
+            &device.compression_algorithms.recompression_global,
+        ) {
+            Ok(_) => {}
+            Err(err) => {
+                warn!(
+                    "Warning: configuring global recompression with {:?} failed: {}",
+                    device.compression_algorithms.recompression_global, err,
+                );
+            }
+        }
+    }
 
     if let Some(ref wb_dev) = device.writeback_dev {
         let writeback_path = device_sysfs_path.join("backing_dev");

tests/test_cases.rs

@@ -326,7 +326,7 @@ fn test_10_example() {
                             ("lzo-rle".into(), "".into()),
                             ("zstd".into(), "level=3".into())
                         ],
-                        recompression_global: "type=idle".into(),
+                        ..Default::default()
                     }
                 );
                 assert_eq!(d.options, "");

zram-generator.conf.example

@@ -38,10 +38,7 @@ zram-resident-limit = maxhotplug * 3/4
 #
 # Subsequent algorithms are used for recompression.
 # Comma-separated parameters may be specified in parentheses.
-#
-# Parameters without a compression algorithm are set as
-# global recompression parameters.
-compression-algorithm = lzo-rle zstd(level=3) (type=idle)
+compression-algorithm = lzo-rle zstd(level=3)
 
 # By default, file systems and swap areas are trimmed on-the-go
 # by setting "discard".