block: Prevent deadlocks when switching elevators

PATCH Applied Damien Le Moal 5 participants 7 messages Sep 8, 2024 – Sep 24, 2024 Block layer

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Damien Le Moal

author

2024-09-08 00:07 UTC #0 lore raw

PATCH 1/1 block: Prevent deadlocks when switching elevators

Commit af2814149883 ("block: freeze the queue in queue_attr_store") changed queue_attr_store() to always freeze a sysfs attribute queue before calling the attribute store() method, to ensure that no IOs are in-flight when an attribute value is being updated.

However, this change created a potential deadlock situation for the scheduler queue attribute as changing the queue elevator with elv_iosched_store() can result in a call to request_module() if the user requested module is not already registered. If the file of the requested module is stored on the block device of the frozen queue, a deadlock will happen as the read operations triggered by request_module() will wait for the queue freeze to end.

Solve this issue by introducing the load_module method in struct queue_sysfs_entry, and to calling this method function in queue_attr_store() before freezing the attribute queue.
The macro definition QUEUE_RW_LOAD_MODULE_ENTRY() is added to define a queue sysfs attribute that needs loading a module.

The definition of the scheduler atrribute is changed to using QUEUE_RW_LOAD_MODULE_ENTRY(), with the function elv_iosched_load_module() defined as the load_module method. elv_iosched_store() can then be simplified to remove the call to request_module().

Reported-by Richard W.M. Jones <[email protected]>

Reported-by Jiri Jaburek <[email protected]>

Closes https://bugzilla.kernel.org/show_bug.cgi?id=219166

Fixes af2814149883 ("block: freeze the queue in queue_attr_store")

Cc [email protected]

Signed-off-by Damien Le Moal <[email protected]>

---
 block/blk-sysfs.c | 22 +++++++++++++++++++++-
 block/elevator.c  | 21 +++++++++++++++------
 block/elevator.h  |  2 ++
 3 files changed, 38 insertions(+), 7 deletions(-)

block/blk-sysfs.c +21 -1

index 60116d13cb80..e85941bec857 100644
@@ -23,6 +23,7 @@
 struct queue_sysfs_entry {
 	struct attribute attr;
 	ssize_t (*show)(struct gendisk *disk, char *page);
+	int (*load_module)(struct gendisk *disk, const char *page, size_t count);
 	ssize_t (*store)(struct gendisk *disk, const char *page, size_t count);
 };

@@ -413,6 +414,14 @@ static struct queue_sysfs_entry _prefix##_entry = {	\
 	.store	= _prefix##_store,			\
 };
 
+#define QUEUE_RW_LOAD_MODULE_ENTRY(_prefix, _name)		\
+static struct queue_sysfs_entry _prefix##_entry = {		\
+	.attr		= { .name = _name, .mode = 0644 },	\
+	.show		= _prefix##_show,			\
+	.load_module	= _prefix##_load_module,		\
+	.store		= _prefix##_store,			\
+}
+
 QUEUE_RW_ENTRY(queue_requests, "nr_requests");
 QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
 QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");

@@ -420,7 +429,7 @@ QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
 QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
 QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
 QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
-QUEUE_RW_ENTRY(elv_iosched, "scheduler");
+QUEUE_RW_LOAD_MODULE_ENTRY(elv_iosched, "scheduler");
 
 QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
 QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");

@@ -670,6 +679,17 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
 	if (!entry->store)
 		return -EIO;
 
+	/*
+	 * If the attribute needs to load a module, do it before freezing the
+	 * queue to ensure that the module file can be read when the request
+	 * queue is the one for the device storing the module file.
+	 */
+	if (entry->load_module) {
+		res = entry->load_module(disk, page, length);
+		if (res)
+			return res;
+	}
+
 	blk_mq_freeze_queue(q);
 	mutex_lock(&q->sysfs_lock);
 	res = entry->store(disk, page, length);

block/elevator.c +15 -6

index f13d552a32c8..c355b55d0107 100644
@@ -698,17 +698,26 @@ static int elevator_change(struct request_queue *q, const char *elevator_name)
 		return 0;
 
 	e = elevator_find_get(q, elevator_name);
-	if (!e) {
-		request_module("%s-iosched", elevator_name);
-		e = elevator_find_get(q, elevator_name);
-		if (!e)
-			return -EINVAL;
-	}
+	if (!e)
+		return -EINVAL;
 	ret = elevator_switch(q, e);
 	elevator_put(e);
 	return ret;
 }
 
+int elv_iosched_load_module(struct gendisk *disk, const char *buf,
+			    size_t count)
+{
+	char elevator_name[ELV_NAME_MAX];
+
+	if (!elv_support_iosched(disk->queue))
+		return -EOPNOTSUPP;
+
+	strscpy(elevator_name, buf, sizeof(elevator_name));
+
+	return request_module("%s-iosched", strstrip(elevator_name));
+}
+
 ssize_t elv_iosched_store(struct gendisk *disk, const char *buf,
 			  size_t count)
 {

block/elevator.h +2 -0

index 3fe18e1a8692..2a78544bf201 100644
@@ -148,6 +148,8 @@ extern void elv_unregister(struct elevator_type *);
  * io scheduler sysfs switching
  */
 ssize_t elv_iosched_show(struct gendisk *disk, char *page);
+int elv_iosched_load_module(struct gendisk *disk, const char *page,
+			    size_t count);
 ssize_t elv_iosched_store(struct gendisk *disk, const char *page, size_t count);
 
 extern bool elv_bio_merge_ok(struct request *, struct bio *);

Signature · 1 line

2.46.0

Richard W.M. Jones

Tested-by on v1 1/1

2024-09-08 10:20 UTC #1 lore raw

Quoted 25 lines · Damien Le Moal

Commit af2814149883 ("block: freeze the queue in queue_attr_store") changed queue_attr_store() to always freeze a sysfs attribute queue before calling the attribute store() method, to ensure that no IOs are in-flight when an attribute value is being updated.
However, this change created a potential deadlock situation for the scheduler queue attribute as changing the queue elevator with elv_iosched_store() can result in a call to request_module() if the user requested module is not already registered. If the file of the requested module is stored on the block device of the frozen queue, a deadlock will happen as the read operations triggered by request_module() will wait for the queue freeze to end.
Solve this issue by introducing the load_module method in struct queue_sysfs_entry, and to calling this method function in queue_attr_store() before freezing the attribute queue.
The macro definition QUEUE_RW_LOAD_MODULE_ENTRY() is added to define a queue sysfs attribute that needs loading a module.
The definition of the scheduler atrribute is changed to using QUEUE_RW_LOAD_MODULE_ENTRY(), with the function elv_iosched_load_module() defined as the load_module method. elv_iosched_store() can then be simplified to remove the call to request_module().

Quoted 6 lines

Reported-by Richard W.M. Jones <[email protected]>
Reported-by Jiri Jaburek <[email protected]>
Closes https://bugzilla.kernel.org/show_bug.cgi?id=219166
Fixes af2814149883 ("block: freeze the queue in queue_attr_store")
Cc [email protected]
Signed-off-by Damien Le Moal <[email protected]>

I tested this (using my "unreliable" test!), and it passed 5,000 iterations, so:

Tested-by Richard W.M. Jones <[email protected]>

Thanks,

Rich.

Quoted 112 lines

---
 block/blk-sysfs.c | 22 +++++++++++++++++++++-
 block/elevator.c  | 21 +++++++++++++++------
 block/elevator.h  |  2 ++
 3 files changed, 38 insertions(+), 7 deletions(-)

block/blk-sysfs.c +21 -1

index 60116d13cb80..e85941bec857 100644
@@ -23,6 +23,7 @@
 struct queue_sysfs_entry {
 	struct attribute attr;
 	ssize_t (*show)(struct gendisk *disk, char *page);
+	int (*load_module)(struct gendisk *disk, const char *page, size_t count);
 	ssize_t (*store)(struct gendisk *disk, const char *page, size_t count);
 };

@@ -413,6 +414,14 @@ static struct queue_sysfs_entry _prefix##_entry = {	\
 	.store	= _prefix##_store,			\
 };
 
+#define QUEUE_RW_LOAD_MODULE_ENTRY(_prefix, _name)		\
+static struct queue_sysfs_entry _prefix##_entry = {		\
+	.attr		= { .name = _name, .mode = 0644 },	\
+	.show		= _prefix##_show,			\
+	.load_module	= _prefix##_load_module,		\
+	.store		= _prefix##_store,			\
+}
+
 QUEUE_RW_ENTRY(queue_requests, "nr_requests");
 QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
 QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");

@@ -420,7 +429,7 @@ QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
 QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
 QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
 QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
-QUEUE_RW_ENTRY(elv_iosched, "scheduler");
+QUEUE_RW_LOAD_MODULE_ENTRY(elv_iosched, "scheduler");
 
 QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
 QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");

@@ -670,6 +679,17 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
 	if (!entry->store)
 		return -EIO;
 
+	/*
+	 * If the attribute needs to load a module, do it before freezing the
+	 * queue to ensure that the module file can be read when the request
+	 * queue is the one for the device storing the module file.
+	 */
+	if (entry->load_module) {
+		res = entry->load_module(disk, page, length);
+		if (res)
+			return res;
+	}
+
 	blk_mq_freeze_queue(q);
 	mutex_lock(&q->sysfs_lock);
 	res = entry->store(disk, page, length);

block/elevator.c +15 -6

index f13d552a32c8..c355b55d0107 100644
@@ -698,17 +698,26 @@ static int elevator_change(struct request_queue *q, const char *elevator_name)
 		return 0;
 
 	e = elevator_find_get(q, elevator_name);
-	if (!e) {
-		request_module("%s-iosched", elevator_name);
-		e = elevator_find_get(q, elevator_name);
-		if (!e)
-			return -EINVAL;
-	}
+	if (!e)
+		return -EINVAL;
 	ret = elevator_switch(q, e);
 	elevator_put(e);
 	return ret;
 }
 
+int elv_iosched_load_module(struct gendisk *disk, const char *buf,
+			    size_t count)
+{
+	char elevator_name[ELV_NAME_MAX];
+
+	if (!elv_support_iosched(disk->queue))
+		return -EOPNOTSUPP;
+
+	strscpy(elevator_name, buf, sizeof(elevator_name));
+
+	return request_module("%s-iosched", strstrip(elevator_name));
+}
+
 ssize_t elv_iosched_store(struct gendisk *disk, const char *buf,
 			  size_t count)
 {

block/elevator.h +2 -0

index 3fe18e1a8692..2a78544bf201 100644
@@ -148,6 +148,8 @@ extern void elv_unregister(struct elevator_type *);
  * io scheduler sysfs switching
  */
 ssize_t elv_iosched_show(struct gendisk *disk, char *page);
+int elv_iosched_load_module(struct gendisk *disk, const char *page,
+			    size_t count);
 ssize_t elv_iosched_store(struct gendisk *disk, const char *page, size_t count);
 
 extern bool elv_bio_merge_ok(struct request *, struct bio *);

Signature · 1 line

2.46.0

Signature · 4 lines

Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
nbdkit - Flexible, fast NBD server with plugins
https://gitlab.com/nbdkit/nbdkit

Jens Axboe

maintainer Applied

2024-09-08 14:56 UTC #2 lore raw

In reply to Damien Le Moal

Quoted 13 lines · Damien Le Moal

Commit af2814149883 ("block: freeze the queue in queue_attr_store") changed queue_attr_store() to always freeze a sysfs attribute queue before calling the attribute store() method, to ensure that no IOs are in-flight when an attribute value is being updated.
However, this change created a potential deadlock situation for the scheduler queue attribute as changing the queue elevator with elv_iosched_store() can result in a call to request_module() if the user requested module is not already registered. If the file of the requested module is stored on the block device of the frozen queue, a deadlock will happen as the read operations triggered by request_module() will wait for the queue freeze to end.

Quoted 1 line

[...]

Applied, thanks!

[1/1] block: Prevent deadlocks when switching elevators

      commit: 3c031b721c0ee1d6237719a6a9d7487ef757487b

Best regards,

Signature · 1 line

Jens Axboe

Jiri Slaby

2024-09-24 10:46 UTC #3 lore raw

In reply to Damien Le Moal

Quoted 19 lines · Damien Le Moal

Commit af2814149883 ("block: freeze the queue in queue_attr_store") changed queue_attr_store() to always freeze a sysfs attribute queue before calling the attribute store() method, to ensure that no IOs are in-flight when an attribute value is being updated.
However, this change created a potential deadlock situation for the scheduler queue attribute as changing the queue elevator with elv_iosched_store() can result in a call to request_module() if the user requested module is not already registered. If the file of the requested module is stored on the block device of the frozen queue, a deadlock will happen as the read operations triggered by request_module() will wait for the queue freeze to end.
Solve this issue by introducing the load_module method in struct queue_sysfs_entry, and to calling this method function in queue_attr_store() before freezing the attribute queue.
The macro definition QUEUE_RW_LOAD_MODULE_ENTRY() is added to define a queue sysfs attribute that needs loading a module.

Quoted 5 lines

The definition of the scheduler atrribute is changed to using QUEUE_RW_LOAD_MODULE_ENTRY(), with the function elv_iosched_load_module() defined as the load_module method. elv_iosched_store() can then be simplified to remove the call to request_module().

Hi,

this broke udev rules for loop in 6.11:

Quoted 8 lines

loop1: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop1/queue/scheduler}="none", ignoring: No such file or directory
loop0: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop0/queue/scheduler}="none", ignoring: No such file or directory
loop5: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop5/queue/scheduler}="none", ignoring: No such file or directory
loop3: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop3/queue/scheduler}="none", ignoring: No such file or directory
loop2: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop2/queue/scheduler}="none", ignoring: No such file or directory
loop7: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop7/queue/scheduler}="none", ignoring: No such file or directory
loop4: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop4/queue/scheduler}="none", ignoring: No such file or directory
loop6: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop6/queue/scheduler}="none", ignoring: No such file or directory

60-io-scheduler.rules:

Quoted 6 lines

     1  # Set optimal IO schedulers for HDD and SSD
     2  # Copyright (c) 2021 SUSE LLC
     3
     4  # ## DO NOT EDIT. ##
     5  # To modify the rules, copy this file to /etc/udev/rules.d/60-io-scheduler.rules
     6  # and edit the copy.

Quoted 8 lines

     7  # Please read the section "Tuning I/O performance" in the System Analysis and Tuning Guide
     8  # from the SUSE Documentation.
     9
    10  # --- DO NOT EDIT THIS PART ----
    11  SUBSYSTEM!="block", GOTO="scheduler_end"
    12  ACTION!="add|change", GOTO="scheduler_end"
    13  ENV{DEVTYPE}!="disk", GOTO="scheduler_end"
    14  TEST!="%S%p/queue/scheduler", GOTO="scheduler_end"

It apparently exists here ^^^.

Quoted 11 lines

    15
    16  # For dm devices, the relevant events are "change" events, see 10-dm.rules
    17  ACTION!="change", KERNEL=="dm-*", GOTO="scheduler_end"
    18  # "none" with no brackets means scheduler isn't configurable
    19  ATTR{queue/scheduler}=="none", GOTO="scheduler_end"
    20  # keep our hands off zoned devices, the kernel auto-configures them
    21  ATTR{queue/zoned}!="none", GOTO="scheduler_end"
    22  # Enforce "none" for multipath components.
    23  ENV{DM_MULTIPATH_DEVICE_PATH}=="1", ATTR{queue/scheduler}="none", GOTO="scheduler_end"
    24  # Enforce "none" for loop devices
    25  KERNEL=="loop[0-9]*", ATTR{queue/scheduler}="none", GOTO="scheduler_end"

But cannot be written to ^^^ because it does not exist. What the heck?

Quoted 21 lines

    26
    27  # --- EDIT BELOW HERE after copying to /etc/udev/rules.d ---
    28
    29  # Uncomment these if you want to force virtual devices to use no scheduler
    30  # KERNEL=="vd[a-z]*", ATTR{queue/scheduler}="none", GOTO="scheduler_end"
    31  # KERNEL=="xvd[a-z]*", ATTR{queue/scheduler}="none", GOTO="scheduler_end"
    32
    33  # Leave virtual devices untouched
    34  KERNEL=="vd[a-z]*", GOTO="scheduler_end"
    35  KERNEL=="xvd[a-z]*", GOTO="scheduler_end"
    36
    37  # 1. BFQ scheduler for single-queue HDD
    38  ATTR{queue/rotational}!="0", TEST!="%S%p/mq/1", ATTR{queue/scheduler}="bfq", GOTO="scheduler_end"
    39
    40  # 2. BFQ scheduler for every HDD, including "real" multiqueue
    41  # ATTR{queue/rotational}!="0", ATTR{queue/scheduler}="bfq", GOTO="scheduler_end"
    42
    43  # 3. For "real" multiqueue devices, the kernel defaults to no IO scheduling
    44  # Uncomment this (and select your scheduler) if you need an IO scheduler for them
    45  # TEST=="%S%p/mq/1", ATTR{queue/scheduler}="kyber", GOTO="scheduler_end"
    46

Quoted 8 lines

    47  # 4. BFQ scheduler for every device (uncomment if you need ionice or blk-cgroup features)
    48  # ATTR{queue/scheduler}="bfq", GOTO="scheduler_end"
    49
    50  # 5. mq-deadline is the kernel default for devices with just one hardware queue
    51  # ATTR{queue/scheduler}="mq-deadline"
    52
    53  # --- EDIT ABOVE HERE after copying to /etc/udev/rules.d ---
    54  LABEL="scheduler_end"

Any ideas?

Quoted 108 lines

Reported-by Richard W.M. Jones <[email protected]>

Reported-by Jiri Jaburek <[email protected]>

Closes https://bugzilla.kernel.org/show_bug.cgi?id=219166

Fixes af2814149883 ("block: freeze the queue in queue_attr_store")

Cc [email protected]

Signed-off-by Damien Le Moal <[email protected]>

---
  block/blk-sysfs.c | 22 +++++++++++++++++++++-
  block/elevator.c  | 21 +++++++++++++++------
  block/elevator.h  |  2 ++
  3 files changed, 38 insertions(+), 7 deletions(-)

block/blk-sysfs.c +21 -1

index 60116d13cb80..e85941bec857 100644
@@ -23,6 +23,7 @@
  struct queue_sysfs_entry {
  	struct attribute attr;
  	ssize_t (*show)(struct gendisk *disk, char *page);
+	int (*load_module)(struct gendisk *disk, const char *page, size_t count);
  	ssize_t (*store)(struct gendisk *disk, const char *page, size_t count);
  };

@@ -413,6 +414,14 @@ static struct queue_sysfs_entry _prefix##_entry = {	\
  	.store	= _prefix##_store,			\
  };
 
+#define QUEUE_RW_LOAD_MODULE_ENTRY(_prefix, _name)		\
+static struct queue_sysfs_entry _prefix##_entry = {		\
+	.attr		= { .name = _name, .mode = 0644 },	\
+	.show		= _prefix##_show,			\
+	.load_module	= _prefix##_load_module,		\
+	.store		= _prefix##_store,			\
+}
+
  QUEUE_RW_ENTRY(queue_requests, "nr_requests");
  QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
  QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");

@@ -420,7 +429,7 @@ QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
  QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
  QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
  QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
-QUEUE_RW_ENTRY(elv_iosched, "scheduler");
+QUEUE_RW_LOAD_MODULE_ENTRY(elv_iosched, "scheduler");
 
  QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
  QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");

@@ -670,6 +679,17 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
  	if (!entry->store)
  		return -EIO;
 
+	/*
+	 * If the attribute needs to load a module, do it before freezing the
+	 * queue to ensure that the module file can be read when the request
+	 * queue is the one for the device storing the module file.
+	 */
+	if (entry->load_module) {
+		res = entry->load_module(disk, page, length);
+		if (res)
+			return res;
+	}
+
  	blk_mq_freeze_queue(q);
  	mutex_lock(&q->sysfs_lock);
  	res = entry->store(disk, page, length);

block/elevator.c +15 -6

index f13d552a32c8..c355b55d0107 100644
@@ -698,17 +698,26 @@ static int elevator_change(struct request_queue *q, const char *elevator_name)
  		return 0;
 
  	e = elevator_find_get(q, elevator_name);
-	if (!e) {
-		request_module("%s-iosched", elevator_name);
-		e = elevator_find_get(q, elevator_name);
-		if (!e)
-			return -EINVAL;
-	}
+	if (!e)
+		return -EINVAL;
  	ret = elevator_switch(q, e);
  	elevator_put(e);
  	return ret;
  }
 
+int elv_iosched_load_module(struct gendisk *disk, const char *buf,
+			    size_t count)
+{
+	char elevator_name[ELV_NAME_MAX];
+
+	if (!elv_support_iosched(disk->queue))
+		return -EOPNOTSUPP;
+
+	strscpy(elevator_name, buf, sizeof(elevator_name));
+
+	return request_module("%s-iosched", strstrip(elevator_name));
+}
+
  ssize_t elv_iosched_store(struct gendisk *disk, const char *buf,
  			  size_t count)
  {

block/elevator.h +0 -0

index 3fe18e1a8692..2a78544bf201 100644

block/elevator.h extern void elv_unregister(struct elevator_type *); · line 155

Quoted 8 lines

block/elevator.h +2 -0

@@ -148,6 +148,8 @@ extern void elv_unregister(struct elevator_type *);
   * io scheduler sysfs switching
   */
  ssize_t elv_iosched_show(struct gendisk *disk, char *page);
+int elv_iosched_load_module(struct gendisk *disk, const char *page,
+			    size_t count);
  ssize_t elv_iosched_store(struct gendisk *disk, const char *page, size_t count);
 
  extern bool elv_bio_merge_ok(struct request *, struct bio *);

thanks,

Signature · 2 lines

js
suse labs

Holger Hoffstätte

2024-09-24 13:18 UTC #4 lore raw

Quoted 2 lines · Jiri Slaby

this broke udev rules for loop in 6.11:
Quoted 1 line
loop1: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop1/queue/scheduler}="none", ignoring: No such file or directory

(etc.)

Patch here but it's not in mainline yet:

https://lore.kernel.org/linux-block/[email protected]/

cheers
Holger

Jens Axboe

maintainer

2024-09-24 14:34 UTC #5 lore raw

Quoted 9 lines · Holger Hoffstätte

Quoted 2 lines · Jiri Slaby
this broke udev rules for loop in 6.11:
> loop1: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop1/queue/scheduler}="none", ignoring: No such file or directory
(etc.)
Patch here but it's not in mainline yet:
https://lore.kernel.org/linux-block/[email protected]/

It'll go upstream later this week.

Signature · 1 line

Jens Axboe

Jiri Slaby

2024-09-24 15:55 UTC #6 lore raw

Quoted 5 lines · Jens Axboe

Quoted 4 lines · Holger Hoffstätte
Quoted 2 lines · Jiri Slaby
this broke udev rules for loop in 6.11:
> loop1: /usr/lib/udev/rules.d/60-io-scheduler.rules:25 Failed to write ATTR{/sys/devices/virtual/block/loop1/queue/scheduler}="none", ignoring: No such file or directory

Quoted 7 lines

Quoted 5 lines
(etc.)
Patch here but it's not in mainline yet:
https://lore.kernel.org/linux-block/[email protected]/
It'll go upstream later this week.

FWIW works for me.

thanks,

Signature · 1 line

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