Specifying an initial output buffer size can reduce the number of regenerations of the seq_<output> buffers when the buffer overflows.
Add another version of __seq_open_private that takes an initial buffer size. Signed-off-by: Joe Perches <[email protected]> --- fs/seq_file.c | 31 +++++++++++++++++++++++++++++++ include/linux/seq_file.h | 3 +++ 2 files changed, 34 insertions(+) diff --git a/fs/seq_file.c b/fs/seq_file.c index b8ac757e..d98fa77 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -652,6 +652,37 @@ int seq_open_private(struct file *filp, const struct seq_operations *ops, } EXPORT_SYMBOL(seq_open_private); +void *__seq_open_private_bufsize(struct file *f, + const struct seq_operations *ops, + int psize, size_t bufsize) +{ + int rc; + void *private; + struct seq_file *seq; + + private = kzalloc(psize, GFP_KERNEL); + if (private == NULL) + goto out; + + rc = seq_open(f, ops); + if (rc < 0) + goto out_free; + + seq = f->private_data; + seq->private = private; + + kfree(seq->buf); + seq->buf = seq_buf_alloc(seq->size = round_up(bufsize, PAGE_SIZE)); + + return private; + +out_free: + kfree(private); +out: + return NULL; +} +EXPORT_SYMBOL(__seq_open_private_bufsize); + void seq_putc(struct seq_file *m, char c) { if (m->count >= m->size) diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h index e305b66..719f1b8 100644 --- a/include/linux/seq_file.h +++ b/include/linux/seq_file.h @@ -136,6 +136,9 @@ 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); +void *__seq_open_private_bufsize(struct file *f, + const struct seq_operations *ops, + int psize, size_t bufsize); int seq_open_private(struct file *, const struct seq_operations *, int); int seq_release_private(struct inode *, struct file *); -- 2.8.0.rc4.16.g56331f8
