new helper: single_open_size()
Same as single_open(), but preallocates the buffer of given size.
Doesn't make any sense for sizes up to PAGE_SIZE and doesn't make
sense if output of show() exceeds PAGE_SIZE only rarely - seq_read()
will take care of growing the buffer and redoing show(). If you
_know_ that it will be large, it might make more sense to look into
saner iterator, rather than go with single-shot one. If that's
impossible, single_open_size() might be for you.
Again, don't use that without a good reason; occasionally that's really
the best way to go, but very often there are better solutions.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 68a04a3..2da29ac 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -123,6 +123,7 @@
}
int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
+int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
int single_release(struct inode *, struct file *);
void *__seq_open_private(struct file *, const struct seq_operations *, int);
int seq_open_private(struct file *, const struct seq_operations *, int);