bcachefs: thread_with_file

Abstract out a new helper from the data job code, for connecting a
kthread to a file descriptor.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/chardev.c b/fs/bcachefs/chardev.c
index ba0436ae6b05833869fe9989585ffe74f13f82e4..30a70cef11743ed2596808601037088847151bc6 100644 (file)
--- a/fs/bcachefs/chardev.c
+++ b/fs/bcachefs/chardev.c
@@ -29,6 +29,62 @@ static int copy_to_user_errcode(void __user *to, const void *from, unsigned long
        return copy_to_user(to, from, n) ? -EFAULT : 0;
 }
 
+struct thread_with_file {
+       struct task_struct      *task;
+       int                     ret;
+};
+
+static void thread_with_file_exit(struct thread_with_file *thr)
+{
+       kthread_stop(thr->task);
+       put_task_struct(thr->task);
+}
+
+__printf(4, 0)
+static int run_thread_with_file(struct thread_with_file *thr,
+                               const struct file_operations *fops,
+                               int (*fn)(void *), const char *fmt, ...)
+{
+       va_list args;
+       struct file *file = NULL;
+       int ret, fd = -1;
+       struct printbuf name = PRINTBUF;
+       unsigned fd_flags = O_RDONLY|O_CLOEXEC|O_NONBLOCK;
+
+       va_start(args, fmt);
+       prt_vprintf(&name, fmt, args);
+       va_end(args);
+
+       thr->ret = 0;
+       thr->task = kthread_create(fn, thr, name.buf);
+       ret = PTR_ERR_OR_ZERO(thr->task);
+       if (ret)
+               goto err;
+
+       ret = get_unused_fd_flags(fd_flags);
+       if (ret < 0)
+               goto err_stop_task;
+       fd = ret;
+
+       file = anon_inode_getfile(name.buf, fops, thr, fd_flags);
+       ret = PTR_ERR_OR_ZERO(file);
+       if (ret)
+               goto err_put_fd;
+
+       fd_install(fd, file);
+       get_task_struct(thr->task);
+       wake_up_process(thr->task);
+       printbuf_exit(&name);
+       return fd;
+err_put_fd:
+       put_unused_fd(fd);
+err_stop_task:
+       kthread_stop(thr->task);
+err:
+       printbuf_exit(&name);
+       return ret;
+}
+
 /* returns with ref on ca->ref */
 static struct bch_dev *bch2_device_lookup(struct bch_fs *c, u64 dev,
                                          unsigned flags)
@@ -299,31 +355,27 @@ static long bch2_ioctl_disk_set_state(struct bch_fs *c,
 }
 
 struct bch_data_ctx {
+       struct thread_with_file         thr;
+
        struct bch_fs                   *c;
        struct bch_ioctl_data           arg;
        struct bch_move_stats           stats;
-
-       int                             ret;
-
-       struct task_struct              *thread;
 };
 
 static int bch2_data_thread(void *arg)
 {
-       struct bch_data_ctx *ctx = arg;
-
-       ctx->ret = bch2_data_job(ctx->c, &ctx->stats, ctx->arg);
+       struct bch_data_ctx *ctx = container_of(arg, struct bch_data_ctx, thr);
 
+       ctx->thr.ret = bch2_data_job(ctx->c, &ctx->stats, ctx->arg);
        ctx->stats.data_type = U8_MAX;
        return 0;
 }
 
 static int bch2_data_job_release(struct inode *inode, struct file *file)
 {
-       struct bch_data_ctx *ctx = file->private_data;
+       struct bch_data_ctx *ctx = container_of(file->private_data, struct bch_data_ctx, thr);
 
-       kthread_stop(ctx->thread);
-       put_task_struct(ctx->thread);
+       thread_with_file_exit(&ctx->thr);
        kfree(ctx);
        return 0;
 }
@@ -331,7 +383,7 @@ static int bch2_data_job_release(struct inode *inode, struct file *file)
 static ssize_t bch2_data_job_read(struct file *file, char __user *buf,
                                  size_t len, loff_t *ppos)
 {
-       struct bch_data_ctx *ctx = file->private_data;
+       struct bch_data_ctx *ctx = container_of(file->private_data, struct bch_data_ctx, thr);
        struct bch_fs *c = ctx->c;
        struct bch_ioctl_data_event e = {
                .type                   = BCH_DATA_EVENT_PROGRESS,
@@ -357,10 +409,8 @@ static const struct file_operations bcachefs_data_ops = {
 static long bch2_ioctl_data(struct bch_fs *c,
                            struct bch_ioctl_data arg)
 {
-       struct bch_data_ctx *ctx = NULL;
-       struct file *file = NULL;
-       unsigned flags = O_RDONLY|O_CLOEXEC|O_NONBLOCK;
-       int ret, fd = -1;
+       struct bch_data_ctx *ctx;
+       int ret;
 
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
@@ -375,36 +425,12 @@ static long bch2_ioctl_data(struct bch_fs *c,
        ctx->c = c;
        ctx->arg = arg;
 
-       ctx->thread = kthread_create(bch2_data_thread, ctx,
-                                    "bch-data/%s", c->name);
-       if (IS_ERR(ctx->thread)) {
-               ret = PTR_ERR(ctx->thread);
-               goto err;
-       }
-
-       ret = get_unused_fd_flags(flags);
+       ret = run_thread_with_file(&ctx->thr,
+                                  &bcachefs_data_ops,
+                                  bch2_data_thread,
+                                  "bch-data/%s", c->name);
        if (ret < 0)
-               goto err;
-       fd = ret;
-
-       file = anon_inode_getfile("[bcachefs]", &bcachefs_data_ops, ctx, flags);
-       if (IS_ERR(file)) {
-               ret = PTR_ERR(file);
-               goto err;
-       }
-
-       fd_install(fd, file);
-
-       get_task_struct(ctx->thread);
-       wake_up_process(ctx->thread);
-
-       return fd;
-err:
-       if (fd >= 0)
-               put_unused_fd(fd);
-       if (!IS_ERR_OR_NULL(ctx->thread))
-               kthread_stop(ctx->thread);
-       kfree(ctx);
+               kfree(ctx);
        return ret;
 }