[PATCH 07/10] thread_with_file: Lift from bcachefs

From: Darrick J. Wong
Date: Fri Feb 23 2024 - 20:16:35 EST

From: Kent Overstreet <kent.overstreet@xxxxxxxxx>

thread_with_file and thread_with_stdio are abstractions for connecting
kthreads to file descriptors, which is handy for all sorts of things -
the running kthread has its lifetime connected to the file descriptor,
which means an asynchronous job running in the kernel can easily exit in
response to a ctrl-c, and the file descriptor also provides a
communications channel.

Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
MAINTAINERS | 9 +
fs/bcachefs/Kconfig | 1
fs/bcachefs/Makefile | 1
fs/bcachefs/bcachefs.h | 2
fs/bcachefs/chardev.c | 10 -
fs/bcachefs/error.c | 4
fs/bcachefs/super.c | 4
include/linux/thread_with_file.h | 35 ++-
include/linux/thread_with_file_types.h | 8 -
lib/Kconfig | 3
lib/Makefile | 1
lib/thread_with_file.c | 326 ++++++++++++++++----------------
12 files changed, 212 insertions(+), 192 deletions(-)
rename fs/bcachefs/thread_with_file.h => include/linux/thread_with_file.h (63%)
rename fs/bcachefs/thread_with_file_types.h => include/linux/thread_with_file_types.h (64%)
rename fs/bcachefs/thread_with_file.c => lib/thread_with_file.c (79%)


diff --git a/MAINTAINERS b/MAINTAINERS
index 97905e0d57a52..5799134b24737 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21888,6 +21888,15 @@ F: Documentation/userspace-api/media/drivers/thp7312.rst
F: drivers/media/i2c/thp7312.c
F: include/uapi/linux/thp7312.h

+THREAD WITH FILE
+M: Kent Overstreet <kent.overstreet@xxxxxxxxx>
+M: Darrick J. Wong <djwong@xxxxxxxxxx>
+L: linux-bcachefs@xxxxxxxxxxxxxxx
+S: Maintained
+F: include/linux/thread_with_file.c
+F: include/linux/thread_with_file_types.c
+F: lib/thread_with_file.c
+
THUNDERBOLT DMA TRAFFIC TEST DRIVER
M: Isaac Hazan <isaac.hazan@xxxxxxxxx>
L: linux-usb@xxxxxxxxxxxxxxx
diff --git a/fs/bcachefs/Kconfig b/fs/bcachefs/Kconfig
index 8c587ddd2f85e..08073d76e5a42 100644
--- a/fs/bcachefs/Kconfig
+++ b/fs/bcachefs/Kconfig
@@ -25,6 +25,7 @@ config BCACHEFS_FS
select SRCU
select SYMBOLIC_ERRNAME
select TIME_STATS
+ select THREAD_WITH_FILE
help
The bcachefs filesystem - a modern, copy on write filesystem, with
support for multiple devices, compression, checksumming, etc.
diff --git a/fs/bcachefs/Makefile b/fs/bcachefs/Makefile
index bb17d146b0900..d335b6572d72d 100644
--- a/fs/bcachefs/Makefile
+++ b/fs/bcachefs/Makefile
@@ -80,7 +80,6 @@ bcachefs-y := \
super-io.o \
sysfs.o \
tests.o \
- thread_with_file.o \
trace.o \
two_state_shared_lock.o \
util.o \
diff --git a/fs/bcachefs/bcachefs.h b/fs/bcachefs/bcachefs.h
index 04e4a65909a4f..5f801256e8740 100644
--- a/fs/bcachefs/bcachefs.h
+++ b/fs/bcachefs/bcachefs.h
@@ -200,6 +200,7 @@
#include <linux/seqlock.h>
#include <linux/shrinker.h>
#include <linux/srcu.h>
+#include <linux/thread_with_file_types.h>
#include <linux/time_stats.h>
#include <linux/types.h>
#include <linux/workqueue.h>
@@ -466,7 +467,6 @@ enum bch_time_stats {
#include "replicas_types.h"
#include "subvolume_types.h"
#include "super_types.h"
-#include "thread_with_file_types.h"

/* Number of nodes btree coalesce will try to coalesce at once */
#define GC_MERGE_NODES 4U
diff --git a/fs/bcachefs/chardev.c b/fs/bcachefs/chardev.c
index 11711f54057e1..4cbda66bb6e0f 100644
--- a/fs/bcachefs/chardev.c
+++ b/fs/bcachefs/chardev.c
@@ -11,7 +11,6 @@
#include "replicas.h"
#include "super.h"
#include "super-io.h"
-#include "thread_with_file.h"

#include <linux/cdev.h>
#include <linux/device.h>
@@ -20,6 +19,7 @@
#include <linux/major.h>
#include <linux/sched/task.h>
#include <linux/slab.h>
+#include <linux/thread_with_file.h>
#include <linux/uaccess.h>

__must_check
@@ -217,7 +217,7 @@ static long bch2_ioctl_fsck_offline(struct bch_ioctl_fsck_offline __user *user_a

opt_set(thr->opts, stdio, (u64)(unsigned long)&thr->thr.stdio);

- ret = bch2_run_thread_with_stdio(&thr->thr,
+ ret = run_thread_with_stdio(&thr->thr,
bch2_fsck_thread_exit,
bch2_fsck_offline_thread_fn);
err:
@@ -422,7 +422,7 @@ static int bch2_data_job_release(struct inode *inode, struct file *file)
{
struct bch_data_ctx *ctx = container_of(file->private_data, struct bch_data_ctx, thr);

- bch2_thread_with_file_exit(&ctx->thr);
+ thread_with_file_exit(&ctx->thr);
kfree(ctx);
return 0;
}
@@ -472,7 +472,7 @@ static long bch2_ioctl_data(struct bch_fs *c,
ctx->c = c;
ctx->arg = arg;

- ret = bch2_run_thread_with_file(&ctx->thr,
+ ret = run_thread_with_file(&ctx->thr,
&bcachefs_data_ops,
bch2_data_thread);
if (ret < 0)
@@ -834,7 +834,7 @@ static long bch2_ioctl_fsck_online(struct bch_fs *c,
goto err;
}

- ret = bch2_run_thread_with_stdio(&thr->thr,
+ ret = run_thread_with_stdio(&thr->thr,
bch2_fsck_thread_exit,
bch2_fsck_online_thread_fn);
err:
diff --git a/fs/bcachefs/error.c b/fs/bcachefs/error.c
index d32c8bebe46c3..70a1253959740 100644
--- a/fs/bcachefs/error.c
+++ b/fs/bcachefs/error.c
@@ -2,7 +2,7 @@
#include "bcachefs.h"
#include "error.h"
#include "super.h"
-#include "thread_with_file.h"
+#include <linux/thread_with_file.h>

#define FSCK_ERR_RATELIMIT_NR 10

@@ -105,7 +105,7 @@ static enum ask_yn bch2_fsck_ask_yn(struct bch_fs *c)
do {
bch2_print(c, " (y,n, or Y,N for all errors of this type) ");

- int r = bch2_stdio_redirect_readline(stdio, buf, sizeof(buf) - 1);
+ int r = stdio_redirect_readline(stdio, buf, sizeof(buf) - 1);
if (r < 0)
return YN_NO;
buf[r] = '\0';
diff --git a/fs/bcachefs/super.c b/fs/bcachefs/super.c
index 0cff8c5f3c104..38a87c8fc8235 100644
--- a/fs/bcachefs/super.c
+++ b/fs/bcachefs/super.c
@@ -56,7 +56,6 @@
#include "super.h"
#include "super-io.h"
#include "sysfs.h"
-#include "thread_with_file.h"
#include "trace.h"

#include <linux/backing-dev.h>
@@ -68,6 +67,7 @@
#include <linux/percpu.h>
#include <linux/random.h>
#include <linux/sysfs.h>
+#include <linux/thread_with_file.h>
#include <crypto/hash.h>

MODULE_LICENSE("GPL");
@@ -99,7 +99,7 @@ void __bch2_print(struct bch_fs *c, const char *fmt, ...)
if (fmt[0] == KERN_SOH[0])
fmt += 2;

- bch2_stdio_redirect_vprintf(stdio, true, fmt, args);
+ stdio_redirect_vprintf(stdio, true, fmt, args);
}
va_end(args);
}
diff --git a/fs/bcachefs/thread_with_file.h b/include/linux/thread_with_file.h
similarity index 63%
rename from fs/bcachefs/thread_with_file.h
rename to include/linux/thread_with_file.h
index f06f8ff19a790..54091f7ff3383 100644
--- a/fs/bcachefs/thread_with_file.h
+++ b/include/linux/thread_with_file.h
@@ -1,8 +1,11 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _BCACHEFS_THREAD_WITH_FILE_H
-#define _BCACHEFS_THREAD_WITH_FILE_H
+/*
+ * (C) 2022-2024 Kent Overstreet <kent.overstreet@xxxxxxxxx>
+ */
+#ifndef _LINUX_THREAD_WITH_FILE_H
+#define _LINUX_THREAD_WITH_FILE_H

-#include "thread_with_file_types.h"
+#include <linux/thread_with_file_types.h>

/*
* Thread with file: Run a kthread and connect it to a file descriptor, so that
@@ -13,7 +16,7 @@
*
* thread_with_file, the low level version.
* You get to define the full file_operations, including your release function,
- * which means that you must call bch2_thread_with_file_exit() from your
+ * which means that you must call thread_with_file_exit() from your
* .release method
*
* thread_with_stdio, the higher level version
@@ -44,10 +47,10 @@ struct thread_with_file {
bool done;
};

-void bch2_thread_with_file_exit(struct thread_with_file *);
-int bch2_run_thread_with_file(struct thread_with_file *,
- const struct file_operations *,
- int (*fn)(void *));
+void thread_with_file_exit(struct thread_with_file *);
+int run_thread_with_file(struct thread_with_file *,
+ const struct file_operations *,
+ int (*fn)(void *));

struct thread_with_stdio {
struct thread_with_file thr;
@@ -56,13 +59,13 @@ struct thread_with_stdio {
void (*fn)(struct thread_with_stdio *);
};

-int bch2_run_thread_with_stdio(struct thread_with_stdio *,
- void (*exit)(struct thread_with_stdio *),
- void (*fn)(struct thread_with_stdio *));
-int bch2_stdio_redirect_read(struct stdio_redirect *, char *, size_t);
-int bch2_stdio_redirect_readline(struct stdio_redirect *, char *, size_t);
+int run_thread_with_stdio(struct thread_with_stdio *,
+ void (*exit)(struct thread_with_stdio *),
+ void (*fn)(struct thread_with_stdio *));
+int stdio_redirect_read(struct stdio_redirect *, char *, size_t);
+int stdio_redirect_readline(struct stdio_redirect *, char *, size_t);

-__printf(3, 0) void bch2_stdio_redirect_vprintf(struct stdio_redirect *, bool, const char *, va_list);
-__printf(3, 4) void bch2_stdio_redirect_printf(struct stdio_redirect *, bool, const char *, ...);
+__printf(3, 0) void stdio_redirect_vprintf(struct stdio_redirect *, bool, const char *, va_list);
+__printf(3, 4) void stdio_redirect_printf(struct stdio_redirect *, bool, const char *, ...);

-#endif /* _BCACHEFS_THREAD_WITH_FILE_H */
+#endif /* _LINUX_THREAD_WITH_FILE_H */
diff --git a/fs/bcachefs/thread_with_file_types.h b/include/linux/thread_with_file_types.h
similarity index 64%
rename from fs/bcachefs/thread_with_file_types.h
rename to include/linux/thread_with_file_types.h
index 41990756aa261..98d0ad1253221 100644
--- a/fs/bcachefs/thread_with_file_types.h
+++ b/include/linux/thread_with_file_types.h
@@ -1,8 +1,10 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _BCACHEFS_THREAD_WITH_FILE_TYPES_H
-#define _BCACHEFS_THREAD_WITH_FILE_TYPES_H
+#ifndef _LINUX_THREAD_WITH_FILE_TYPES_H
+#define _LINUX_THREAD_WITH_FILE_TYPES_H

#include <linux/darray_types.h>
+#include <linux/spinlock_types.h>
+#include <linux/wait.h>

struct stdio_buf {
spinlock_t lock;
@@ -20,4 +22,4 @@ struct stdio_redirect {
bool done;
};

-#endif /* _BCACHEFS_THREAD_WITH_FILE_TYPES_H */
+#endif /* _LINUX_THREAD_WITH_FILE_TYPES_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 3ba8b965f8c7e..9258d04e939db 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -789,3 +789,6 @@ config FIRMWARE_TABLE
config TIME_STATS
tristate
select MEAN_AND_VARIANCE
+
+config THREAD_WITH_FILE
+ tristate
diff --git a/lib/Makefile b/lib/Makefile
index 830907bb8fc85..e77304f69df03 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -371,6 +371,7 @@ obj-$(CONFIG_SBITMAP) += sbitmap.o
obj-$(CONFIG_PARMAN) += parman.o

obj-$(CONFIG_TIME_STATS) += time_stats.o
+obj-$(CONFIG_THREAD_WITH_FILE) += thread_with_file.o

obj-y += group_cpus.o

diff --git a/fs/bcachefs/thread_with_file.c b/lib/thread_with_file.c
similarity index 79%
rename from fs/bcachefs/thread_with_file.c
rename to lib/thread_with_file.c
index dde9679b68b42..092996ca43fe7 100644
--- a/fs/bcachefs/thread_with_file.c
+++ b/lib/thread_with_file.c
@@ -1,26 +1,160 @@
// SPDX-License-Identifier: GPL-2.0
-#ifndef NO_BCACHEFS_FS
-
-#include "bcachefs.h"
-#include "thread_with_file.h"
-
+/*
+ * (C) 2022-2024 Kent Overstreet <kent.overstreet@xxxxxxxxx>
+ */
#include <linux/anon_inodes.h>
+#include <linux/darray.h>
#include <linux/file.h>
#include <linux/kthread.h>
+#include <linux/module.h>
#include <linux/pagemap.h>
#include <linux/poll.h>
+#include <linux/thread_with_file.h>

-void bch2_thread_with_file_exit(struct thread_with_file *thr)
+/* stdio_redirect */
+
+#define STDIO_REDIRECT_BUFSIZE 4096
+
+static bool stdio_redirect_has_input(struct stdio_redirect *stdio)
+{
+ return stdio->input.buf.nr || stdio->done;
+}
+
+static bool stdio_redirect_has_output(struct stdio_redirect *stdio)
+{
+ return stdio->output.buf.nr || stdio->done;
+}
+
+static bool stdio_redirect_has_input_space(struct stdio_redirect *stdio)
+{
+ return stdio->input.buf.nr < STDIO_REDIRECT_BUFSIZE || stdio->done;
+}
+
+static bool stdio_redirect_has_output_space(struct stdio_redirect *stdio)
+{
+ return stdio->output.buf.nr < STDIO_REDIRECT_BUFSIZE || stdio->done;
+}
+
+static void stdio_buf_init(struct stdio_buf *buf)
+{
+ spin_lock_init(&buf->lock);
+ init_waitqueue_head(&buf->wait);
+ darray_init(&buf->buf);
+}
+
+int stdio_redirect_read(struct stdio_redirect *stdio, char *ubuf, size_t len)
+{
+ struct stdio_buf *buf = &stdio->input;
+
+ wait_event(buf->wait, stdio_redirect_has_input(stdio));
+ if (stdio->done)
+ return -1;
+
+ spin_lock(&buf->lock);
+ int ret = min(len, buf->buf.nr);
+ memcpy(ubuf, buf->buf.data, ret);
+ darray_remove_items(&buf->buf, buf->buf.data, ret);
+ spin_unlock(&buf->lock);
+
+ wake_up(&buf->wait);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(stdio_redirect_read);
+
+int stdio_redirect_readline(struct stdio_redirect *stdio, char *ubuf, size_t len)
+{
+ struct stdio_buf *buf = &stdio->input;
+ size_t copied = 0;
+ ssize_t ret = 0;
+again:
+ wait_event(buf->wait, stdio_redirect_has_input(stdio));
+ if (stdio->done) {
+ ret = -1;
+ goto out;
+ }
+
+ spin_lock(&buf->lock);
+ size_t b = min(len, buf->buf.nr);
+ char *n = memchr(buf->buf.data, '\n', b);
+ if (n)
+ b = min_t(size_t, b, n + 1 - buf->buf.data);
+ memcpy(ubuf, buf->buf.data, b);
+ darray_remove_items(&buf->buf, buf->buf.data, b);
+ ubuf += b;
+ len -= b;
+ copied += b;
+ spin_unlock(&buf->lock);
+
+ wake_up(&buf->wait);
+
+ if (!n && len)
+ goto again;
+out:
+ return copied ?: ret;
+}
+EXPORT_SYMBOL_GPL(stdio_redirect_readline);
+
+__printf(3, 0)
+static void darray_vprintf(darray_char *out, gfp_t gfp, const char *fmt, va_list args)
+{
+ size_t len;
+
+ do {
+ va_list args2;
+ va_copy(args2, args);
+
+ len = vsnprintf(out->data + out->nr, darray_room(*out), fmt, args2);
+ } while (len + 1 > darray_room(*out) && !darray_make_room_gfp(out, len + 1, gfp));
+
+ out->nr += min(len, darray_room(*out));
+}
+
+void stdio_redirect_vprintf(struct stdio_redirect *stdio, bool nonblocking,
+ const char *fmt, va_list args)
+{
+ struct stdio_buf *buf = &stdio->output;
+ unsigned long flags;
+
+ if (!nonblocking)
+ wait_event(buf->wait, stdio_redirect_has_output_space(stdio));
+ else if (!stdio_redirect_has_output_space(stdio))
+ return;
+ if (stdio->done)
+ return;
+
+ spin_lock_irqsave(&buf->lock, flags);
+ darray_vprintf(&buf->buf, nonblocking ? GFP_NOWAIT : GFP_KERNEL, fmt, args);
+ spin_unlock_irqrestore(&buf->lock, flags);
+
+ wake_up(&buf->wait);
+}
+EXPORT_SYMBOL_GPL(stdio_redirect_vprintf);
+
+void stdio_redirect_printf(struct stdio_redirect *stdio, bool nonblocking,
+ const char *fmt, ...)
+{
+
+ va_list args;
+ va_start(args, fmt);
+ stdio_redirect_vprintf(stdio, nonblocking, fmt, args);
+ va_end(args);
+}
+EXPORT_SYMBOL_GPL(stdio_redirect_printf);
+
+/* thread with file: */
+
+void thread_with_file_exit(struct thread_with_file *thr)
{
if (thr->task) {
kthread_stop(thr->task);
put_task_struct(thr->task);
}
}
+EXPORT_SYMBOL_GPL(thread_with_file_exit);

-int bch2_run_thread_with_file(struct thread_with_file *thr,
- const struct file_operations *fops,
- int (*fn)(void *))
+int run_thread_with_file(struct thread_with_file *thr,
+ const struct file_operations *fops,
+ int (*fn)(void *))
{
struct file *file = NULL;
int ret, fd = -1;
@@ -63,37 +197,7 @@ int bch2_run_thread_with_file(struct thread_with_file *thr,
kthread_stop(thr->task);
return ret;
}
-
-/* stdio_redirect */
-
-static bool stdio_redirect_has_input(struct stdio_redirect *stdio)
-{
- return stdio->input.buf.nr || stdio->done;
-}
-
-static bool stdio_redirect_has_output(struct stdio_redirect *stdio)
-{
- return stdio->output.buf.nr || stdio->done;
-}
-
-#define STDIO_REDIRECT_BUFSIZE 4096
-
-static bool stdio_redirect_has_input_space(struct stdio_redirect *stdio)
-{
- return stdio->input.buf.nr < STDIO_REDIRECT_BUFSIZE || stdio->done;
-}
-
-static bool stdio_redirect_has_output_space(struct stdio_redirect *stdio)
-{
- return stdio->output.buf.nr < STDIO_REDIRECT_BUFSIZE || stdio->done;
-}
-
-static void stdio_buf_init(struct stdio_buf *buf)
-{
- spin_lock_init(&buf->lock);
- init_waitqueue_head(&buf->wait);
- darray_init(&buf->buf);
-}
+EXPORT_SYMBOL_GPL(run_thread_with_file);

/* thread_with_stdio */

@@ -126,10 +230,7 @@ static ssize_t thread_with_stdio_read(struct file *file, char __user *ubuf,
ubuf += b;
len -= b;
copied += b;
- buf->buf.nr -= b;
- memmove(buf->buf.data,
- buf->buf.data + b,
- buf->buf.nr);
+ darray_remove_items(&buf->buf, buf->buf.data, b);
}
spin_unlock_irq(&buf->lock);
}
@@ -137,18 +238,6 @@ static ssize_t thread_with_stdio_read(struct file *file, char __user *ubuf,
return copied ?: ret;
}

-static int thread_with_stdio_release(struct inode *inode, struct file *file)
-{
- struct thread_with_stdio *thr =
- container_of(file->private_data, struct thread_with_stdio, thr);
-
- bch2_thread_with_file_exit(&thr->thr);
- darray_exit(&thr->stdio.input.buf);
- darray_exit(&thr->stdio.output.buf);
- thr->exit(thr);
- return 0;
-}
-
static ssize_t thread_with_stdio_write(struct file *file, const char __user *ubuf,
size_t len, loff_t *ppos)
{
@@ -221,6 +310,18 @@ static __poll_t thread_with_stdio_poll(struct file *file, struct poll_table_stru
return mask;
}

+static int thread_with_stdio_release(struct inode *inode, struct file *file)
+{
+ struct thread_with_stdio *thr =
+ container_of(file->private_data, struct thread_with_stdio, thr);
+
+ thread_with_file_exit(&thr->thr);
+ darray_exit(&thr->stdio.input.buf);
+ darray_exit(&thr->stdio.output.buf);
+ thr->exit(thr);
+ return 0;
+}
+
static const struct file_operations thread_with_stdio_fops = {
.llseek = no_llseek,
.read = thread_with_stdio_read,
@@ -242,117 +343,18 @@ static int thread_with_stdio_fn(void *arg)
return 0;
}

-int bch2_run_thread_with_stdio(struct thread_with_stdio *thr,
- void (*exit)(struct thread_with_stdio *),
- void (*fn)(struct thread_with_stdio *))
+int run_thread_with_stdio(struct thread_with_stdio *thr,
+ void (*exit)(struct thread_with_stdio *),
+ void (*fn)(struct thread_with_stdio *))
{
stdio_buf_init(&thr->stdio.input);
stdio_buf_init(&thr->stdio.output);
thr->exit = exit;
thr->fn = fn;

- return bch2_run_thread_with_file(&thr->thr, &thread_with_stdio_fops, thread_with_stdio_fn);
+ return run_thread_with_file(&thr->thr, &thread_with_stdio_fops, thread_with_stdio_fn);
}
+EXPORT_SYMBOL_GPL(run_thread_with_stdio);

-int bch2_stdio_redirect_read(struct stdio_redirect *stdio, char *ubuf, size_t len)
-{
- struct stdio_buf *buf = &stdio->input;
-
- wait_event(buf->wait, stdio_redirect_has_input(stdio));
- if (stdio->done)
- return -1;
-
- spin_lock(&buf->lock);
- int ret = min(len, buf->buf.nr);
- buf->buf.nr -= ret;
- memcpy(ubuf, buf->buf.data, ret);
- memmove(buf->buf.data,
- buf->buf.data + ret,
- buf->buf.nr);
- spin_unlock(&buf->lock);
-
- wake_up(&buf->wait);
- return ret;
-}
-
-int bch2_stdio_redirect_readline(struct stdio_redirect *stdio, char *ubuf, size_t len)
-{
- struct stdio_buf *buf = &stdio->input;
- size_t copied = 0;
- ssize_t ret = 0;
-again:
- wait_event(buf->wait, stdio_redirect_has_input(stdio));
- if (stdio->done) {
- ret = -1;
- goto out;
- }
-
- spin_lock(&buf->lock);
- size_t b = min(len, buf->buf.nr);
- char *n = memchr(buf->buf.data, '\n', b);
- if (n)
- b = min_t(size_t, b, n + 1 - buf->buf.data);
- buf->buf.nr -= b;
- memcpy(ubuf, buf->buf.data, b);
- memmove(buf->buf.data,
- buf->buf.data + b,
- buf->buf.nr);
- ubuf += b;
- len -= b;
- copied += b;
- spin_unlock(&buf->lock);
-
- wake_up(&buf->wait);
-
- if (!n && len)
- goto again;
-out:
- return copied ?: ret;
-}
-
-__printf(3, 0)
-static void bch2_darray_vprintf(darray_char *out, gfp_t gfp, const char *fmt, va_list args)
-{
- size_t len;
-
- do {
- va_list args2;
- va_copy(args2, args);
-
- len = vsnprintf(out->data + out->nr, darray_room(*out), fmt, args2);
- } while (len + 1 > darray_room(*out) && !darray_make_room_gfp(out, len + 1, gfp));
-
- out->nr += min(len, darray_room(*out));
-}
-
-void bch2_stdio_redirect_vprintf(struct stdio_redirect *stdio, bool nonblocking,
- const char *fmt, va_list args)
-{
- struct stdio_buf *buf = &stdio->output;
- unsigned long flags;
-
- if (!nonblocking)
- wait_event(buf->wait, stdio_redirect_has_output_space(stdio));
- else if (!stdio_redirect_has_output_space(stdio))
- return;
- if (stdio->done)
- return;
-
- spin_lock_irqsave(&buf->lock, flags);
- bch2_darray_vprintf(&buf->buf, nonblocking ? GFP_NOWAIT : GFP_KERNEL, fmt, args);
- spin_unlock_irqrestore(&buf->lock, flags);
-
- wake_up(&buf->wait);
-}
-
-void bch2_stdio_redirect_printf(struct stdio_redirect *stdio, bool nonblocking,
- const char *fmt, ...)
-{
-
- va_list args;
- va_start(args, fmt);
- bch2_stdio_redirect_vprintf(stdio, nonblocking, fmt, args);
- va_end(args);
-}
-
-#endif /* NO_BCACHEFS_FS */
+MODULE_AUTHOR("Kent Overstreet");
+MODULE_LICENSE("GPL");