The patch titled
kthread: convert loop.c to kthread
has been removed from the -mm tree. Its filename is
kthread-convert-loopc-to-kthread.patch
This patch was dropped because an updated version was merged
------------------------------------------------------
Subject: kthread: convert loop.c to kthread
From: Serge Hallyn <serue@xxxxxxxxxx>
Convert loop.c from the deprecated kernel_thread to kthread. This patch
also simplifies the code a bit. It has passed vigerous testing. The
following script, looptorture.sh, which mounts and unmounts loopback device
1000 times, completes in three terminals simultaneously on different loop
devices. For example, started up screen, created three screens, and typed
each of the following lines into a separate screen:
sh loopback.sh 2
sh loopback.sh 3
sh loopback.sh 4
loopback.sh:
j=0
if [ $# > 0 ]; then
num=$1
else
num="0"
fi
echo "starting loop ($num)"
if [ ! -d /mnt/$num ]; then
mkdir /mnt/$num
fi
dd if=/dev/zero of=/tst/zero$num bs=1M count=100
while [ $j -lt 1000 ]; do
let j=j+1
echo "Doing pass $j"
losetup /dev/loop$num /tst/zero$num
mkfs -t ext2 -b 1024 /dev/loop$num >/dev/null 2>&1
mount -t ext2 /dev/loop$num /mnt/$num
echo hello > /mnt/$num/hw
umount /mnt/$num
losetup -d /dev/loop$num
done
A partial kernel build on a loopback partition also worked fine.
I have not tested encrypted devices, or suspend to loopback device.
Changes since last attempt:
Eliminated lo->lo_done and lo->lo_bh_done completions.
The former is not needed because we can wake up the thread
when we're ready. The latter was used for waking the
loop_thread up when there was something to do or it was
time to quit, and we no longer need this since we simply
wake the thread directly when there's data.
The lo->pending count used to be set at one plus actual
pending actions, and was reduced to 0 only when it was time
to quit. We now use kthread_should_stop() to find out whether
we're done, though we do not actually stop until there are no
pending actions.
Signed-off-by: Serge Hallyn <serue@xxxxxxxxxx>
DESC
kthread-convert-loopc-to-kthread-race-fix
EDESC
Cc: Serge Hallyn <serue@xxxxxxxxxx>
DESC
kthread-convert-loopc-to-kthread-race-fix-fix
EDESC
Cc: Serge Hallyn <serue@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/block/loop.c | 74 ++++++++++++++---------------------------
include/linux/loop.h | 3 -
2 files changed, 28 insertions(+), 49 deletions(-)
diff -puN drivers/block/loop.c~kthread-convert-loopc-to-kthread drivers/block/loop.c
--- a/drivers/block/loop.c~kthread-convert-loopc-to-kthread
+++ a/drivers/block/loop.c
@@ -72,6 +72,7 @@
#include <linux/completion.h>
#include <linux/highmem.h>
#include <linux/gfp.h>
+#include <linux/kthread.h>
#include <asm/uaccess.h>
@@ -524,13 +525,11 @@ static int loop_make_request(request_que
goto out;
lo->lo_pending++;
loop_add_bio(lo, old_bio);
+ wake_up_process(lo->lo_thread);
spin_unlock_irq(&lo->lo_lock);
- complete(&lo->lo_bh_done);
return 0;
out:
- if (lo->lo_pending == 0)
- complete(&lo->lo_bh_done);
spin_unlock_irq(&lo->lo_lock);
bio_io_error(old_bio, old_bio->bi_size);
return 0;
@@ -576,8 +575,6 @@ static int loop_thread(void *data)
struct loop_device *lo = data;
struct bio *bio;
- daemonize("loop%d", lo->lo_number);
-
/*
* loop can be used in an encrypted device,
* hence, it mustn't be stopped at all
@@ -587,47 +584,28 @@ static int loop_thread(void *data)
set_user_nice(current, -20);
- lo->lo_state = Lo_bound;
- lo->lo_pending = 1;
-
- /*
- * complete it, we are running
- */
- complete(&lo->lo_done);
-
for (;;) {
- int pending;
-
- if (wait_for_completion_interruptible(&lo->lo_bh_done))
- continue;
-
spin_lock_irq(&lo->lo_lock);
+ while (lo->lo_pending) {
+ bio = loop_get_bio(lo);
+ lo->lo_pending--;
- /*
- * could be completed because of tear-down, not pending work
- */
- if (unlikely(!lo->lo_pending)) {
spin_unlock_irq(&lo->lo_lock);
- break;
+ BUG_ON(!bio);
+ loop_handle_bio(lo, bio);
+ spin_lock_irq(&lo->lo_lock);
}
- bio = loop_get_bio(lo);
- lo->lo_pending--;
- pending = lo->lo_pending;
- spin_unlock_irq(&lo->lo_lock);
-
- BUG_ON(!bio);
- loop_handle_bio(lo, bio);
-
- /*
- * upped both for pending work and tear-down, lo_pending
- * will hit zero then
- */
- if (unlikely(!pending))
+ if (kthread_should_stop()) {
+ spin_unlock_irq(&lo->lo_lock);
break;
+ }
+ __set_current_state(TASK_INTERRUPTIBLE);
+ spin_unlock_irq(&lo->lo_lock);
+ if (lo->lo_state != Lo_rundown)
+ schedule();
}
- complete(&lo->lo_done);
return 0;
}
@@ -840,10 +818,16 @@ static int loop_set_fd(struct loop_devic
set_blocksize(bdev, lo_blocksize);
- error = kernel_thread(loop_thread, lo, CLONE_KERNEL);
- if (error < 0)
+ lo->lo_thread = kthread_create(loop_thread, lo, "loop%d",
+ lo->lo_number);
+ if (IS_ERR(lo->lo_thread)) {
+ error = PTR_ERR(lo->lo_thread);
+ lo->lo_thread = NULL;
goto out_putf;
- wait_for_completion(&lo->lo_done);
+ }
+ lo->lo_pending = 0;
+ lo->lo_state = Lo_bound;
+ wake_up_process(lo->lo_thread);
return 0;
out_putf:
@@ -905,15 +889,11 @@ static int loop_clr_fd(struct loop_devic
if (filp == NULL)
return -EINVAL;
+ kthread_stop(lo->lo_thread);
spin_lock_irq(&lo->lo_lock);
lo->lo_state = Lo_rundown;
- lo->lo_pending--;
- if (!lo->lo_pending)
- complete(&lo->lo_bh_done);
spin_unlock_irq(&lo->lo_lock);
- wait_for_completion(&lo->lo_done);
-
lo->lo_backing_file = NULL;
loop_release_xfer(lo);
@@ -922,6 +902,7 @@ static int loop_clr_fd(struct loop_devic
lo->lo_device = NULL;
lo->lo_encryption = NULL;
lo->lo_offset = 0;
+ lo->lo_thread = NULL;
lo->lo_sizelimit = 0;
lo->lo_encrypt_key_size = 0;
lo->lo_flags = 0;
@@ -1287,8 +1268,7 @@ static int __init loop_init(void)
if (!lo->lo_queue)
goto out_mem4;
mutex_init(&lo->lo_ctl_mutex);
- init_completion(&lo->lo_done);
- init_completion(&lo->lo_bh_done);
+ lo->lo_thread = NULL;
lo->lo_number = i;
spin_lock_init(&lo->lo_lock);
disk->major = LOOP_MAJOR;
diff -puN include/linux/loop.h~kthread-convert-loopc-to-kthread include/linux/loop.h
--- a/include/linux/loop.h~kthread-convert-loopc-to-kthread
+++ a/include/linux/loop.h
@@ -59,8 +59,7 @@ struct loop_device {
struct bio *lo_bio;
struct bio *lo_biotail;
int lo_state;
- struct completion lo_done;
- struct completion lo_bh_done;
+ struct task_struct *lo_thread;
struct mutex lo_ctl_mutex;
int lo_pending;
_
Patches currently in -mm which might be from serue@xxxxxxxxxx are
origin.patch
kthread-convert-loopc-to-kthread.patch
proc-sysctl-add-_proc_do_string-helper.patch
namespaces-add-nsproxy.patch
namespaces-add-nsproxy-dont-include-compileh.patch
namespaces-incorporate-fs-namespace-into-nsproxy.patch
namespaces-utsname-introduce-temporary-helpers.patch
namespaces-utsname-switch-to-using-uts-namespaces.patch
namespaces-utsname-use-init_utsname-when-appropriate.patch
namespaces-utsname-implement-utsname-namespaces.patch
namespaces-utsname-sysctl-hack.patch
namespaces-utsname-sysctl-hack-fix.patch
namespaces-utsname-remove-system_utsname.patch
namespaces-utsname-implement-clone_newuts-flag.patch
uts-copy-nsproxy-only-when-needed.patch
-
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