[PATCH 26/79] block: rnull: add badblocks support

[Andreas Hindborg]

Add badblocks support to the rnull driver with a configfs interface for
managing bad sectors.

- Configfs attribute for adding/removing bad blocks via "+start-end" and
  "-start-end" syntax.
- Request handling that checks for bad blocks and returns IO errors.
- Updated request completion to handle error status properly.

The badblocks functionality is disabled by default and is enabled when
first bad block is added.

Signed-off-by: Andreas Hindborg <a.hindborg@xxxxxxxxxx>
---
 drivers/block/rnull/configfs.rs | 63 ++++++++++++++++++++++++++++++++++++++---
 drivers/block/rnull/rnull.rs    | 46 ++++++++++++++++++++++++++----
 2 files changed, 100 insertions(+), 9 deletions(-)

diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 18e32a87673aa..61a76addf468b 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -6,9 +6,12 @@
 };
 use kernel::{
     bindings,
-    block::mq::gen_disk::{
-        GenDisk,
-        GenDiskBuilder, //
+    block::{
+        badblocks::BadBlocks,
+        mq::gen_disk::{
+            GenDisk,
+            GenDiskBuilder, //
+        }, //
     },
     c_str,
     configfs::{
@@ -27,7 +30,10 @@
         kstrtobool_bytes,
         CString, //
     },
-    sync::Mutex,
+    sync::{
+        Arc,
+        Mutex, //
+    },
     time, //
 };
 use macros::{
@@ -96,6 +102,7 @@ fn make_group(
                 home_node: 9,
                 discard: 10,
                 no_sched:11,
+                badblocks: 12,
             ],
         };
 
@@ -118,6 +125,7 @@ fn make_group(
                     home_node: bindings::NUMA_NO_NODE,
                     discard: false,
                     no_sched: false,
+                    bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
                 }),
             }),
             core::iter::empty(),
@@ -177,6 +185,7 @@ struct DeviceConfigInner {
     home_node: i32,
     discard: bool,
     no_sched: bool,
+    bad_blocks: Arc<BadBlocks>,
 }
 
 #[vtable]
@@ -212,6 +221,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
                 home_node: guard.home_node,
                 discard: guard.discard,
                 no_sched: guard.no_sched,
+                bad_blocks: guard.bad_blocks.clone(),
             })?);
             guard.powered = true;
         } else if guard.powered && !power_op {
@@ -367,3 +377,48 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
         Ok(())
     }
 }
+
+#[vtable]
+impl configfs::AttributeOperations<12> for DeviceConfig {
+    type Data = DeviceConfig;
+
+    fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
+        let ret = this.data.lock().bad_blocks.show(page, false);
+        if ret < 0 {
+            Err(Error::from_errno(ret as c_int))
+        } else {
+            Ok(ret as usize)
+        }
+    }
+
+    fn store(this: &DeviceConfig, page: &[u8]) -> Result {
+        // This attribute can be set while device is powered.
+
+        for line in core::str::from_utf8(page)?.lines() {
+            let mut chars = line.chars();
+            match chars.next() {
+                Some(sign @ '+' | sign @ '-') => {
+                    if let Some((start, end)) = chars.as_str().split_once('-') {
+                        let start: u64 = start.parse().map_err(|_| EINVAL)?;
+                        let end: u64 = end.parse().map_err(|_| EINVAL)?;
+
+                        if start > end {
+                            return Err(EINVAL);
+                        }
+
+                        this.data.lock().bad_blocks.enable();
+
+                        if sign == '+' {
+                            this.data.lock().bad_blocks.set_bad(start..=end, true)?;
+                        } else {
+                            this.data.lock().bad_blocks.set_good(start..=end)?;
+                        }
+                    }
+                }
+                _ => return Err(EINVAL),
+            }
+        }
+
+        Ok(())
+    }
+}
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index b0008e2f9c398..861392c5b5841 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -9,6 +9,7 @@
     bindings,
     block::{
         self,
+        badblocks::{self, BadBlocks},
         bio::Segment,
         mq::{
             self,
@@ -37,6 +38,10 @@
     str::CString,
     sync::{
         aref::ARef,
+        atomic::{
+            ordering,
+            Atomic, //
+        },
         Arc,
         Mutex, //
     },
@@ -155,6 +160,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
                     home_node: *module_parameters::home_node.value(),
                     discard: *module_parameters::discard.value() != 0,
                     no_sched: *module_parameters::no_sched.value() != 0,
+                    bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
                 })?;
                 disks.push(disk, GFP_KERNEL)?;
             }
@@ -181,6 +187,7 @@ struct NullBlkOptions<'a> {
     home_node: i32,
     discard: bool,
     no_sched: bool,
+    bad_blocks: Arc<BadBlocks>,
 }
 struct NullBlkDevice;
 
@@ -198,6 +205,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
             home_node,
             discard,
             no_sched,
+            bad_blocks,
         } = options;
 
         let mut flags = mq::tag_set::Flags::default();
@@ -226,6 +234,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
                 completion_time,
                 memory_backed,
                 block_size: block_size.into(),
+                bad_blocks,
             }),
             GFP_KERNEL,
         )?;
@@ -327,6 +336,16 @@ fn transfer(
         }
         Ok(())
     }
+
+    fn end_request(rq: Owned<mq::Request<Self>>) {
+        let status = rq.data_ref().error.load(ordering::Relaxed);
+        rq.data_ref().error.store(0, ordering::Relaxed);
+
+        match status {
+            0 => rq.end_ok(),
+            _ => rq.end(bindings::BLK_STS_IOERR),
+        }
+    }
 }
 
 const _CHEKC_STATUS_WIDTH: () = build_assert!((PAGE_SIZE >> SECTOR_SHIFT) <= 64);
@@ -373,12 +392,14 @@ struct QueueData {
     completion_time: Delta,
     memory_backed: bool,
     block_size: u64,
+    bad_blocks: Arc<BadBlocks>,
 }
 
 #[pin_data]
 struct Pdu {
     #[pin]
     timer: kernel::time::hrtimer::HrTimer<Self>,
+    error: Atomic<u32>,
 }
 
 impl HrTimerCallback for Pdu {
@@ -408,6 +429,7 @@ impl Operations for NullBlkDevice {
     fn new_request_data() -> impl PinInit<Self::RequestData> {
         pin_init!(Pdu {
             timer <- kernel::time::hrtimer::HrTimer::new(),
+            error: Atomic::new(0),
         })
     }
 
@@ -417,6 +439,19 @@ fn queue_rq(
         mut rq: Owned<mq::Request<Self>>,
         _is_last: bool,
     ) -> Result {
+        if queue_data.bad_blocks.enabled() {
+            let start = rq.sector();
+            let end = start + u64::from(rq.sectors());
+            if !matches!(
+                queue_data.bad_blocks.check(start..end),
+                badblocks::BlockStatus::None
+            ) {
+                rq.data_ref().error.store(1, ordering::Relaxed);
+            }
+        }
+
+        // TODO: Skip IO if bad block.
+
         if queue_data.memory_backed {
             let tree = &queue_data.tree;
             let command = rq.command();
@@ -437,7 +472,7 @@ fn queue_rq(
         }
 
         match queue_data.irq_mode {
-            IRQMode::None => rq.end_ok(),
+            IRQMode::None => Self::end_request(rq),
             IRQMode::Soft => mq::Request::complete(rq.into()),
             IRQMode::Timer => {
                 OwnableRefCounted::into_shared(rq)
@@ -451,9 +486,10 @@ fn queue_rq(
     fn commit_rqs(_queue_data: Pin<&QueueData>) {}
 
     fn complete(rq: ARef<mq::Request<Self>>) {
-        OwnableRefCounted::try_from_shared(rq)
-            .map_err(|_e| kernel::error::code::EIO)
-            .expect("Failed to complete request")
-            .end_ok();
+        Self::end_request(
+            OwnableRefCounted::try_from_shared(rq)
+                .map_err(|_e| kernel::error::code::EIO)
+                .expect("Failed to complete request"),
+        )
     }
 }

-- 
2.51.2