diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2013-03-31 13:43:23 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-04-09 14:13:29 -0400 |
| commit | 2043f495c7c1a06f7748b5bcd17656d93c95e1a6 (patch) | |
| tree | f3d0368632a1fda88bb385ddfc01600fe450e74f | |
| parent | 70ef457dc92bdd03c0c8d640fce45909166983a1 (diff) | |
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>
| -rw-r--r-- | fs/seq_file.c | 18 | ||||
| -rw-r--r-- | include/linux/seq_file.h | 1 |
2 files changed, 19 insertions, 0 deletions
diff --git a/fs/seq_file.c b/fs/seq_file.c index 38bb59f3f2ad..774c1eb7f1c9 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -599,6 +599,24 @@ int single_open(struct file *file, int (*show)(struct seq_file *, void *), } EXPORT_SYMBOL(single_open); +int single_open_size(struct file *file, int (*show)(struct seq_file *, void *), + void *data, size_t size) +{ + char *buf = kmalloc(size, GFP_KERNEL); + int ret; + if (!buf) + return -ENOMEM; + ret = single_open(file, show, data); + if (ret) { + kfree(buf); + return ret; + } + ((struct seq_file *)file->private_data)->buf = buf; + ((struct seq_file *)file->private_data)->size = size; + return 0; +} +EXPORT_SYMBOL(single_open_size); + int single_release(struct inode *inode, struct file *file) { const struct seq_operations *op = ((struct seq_file *)file->private_data)->op; diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h index 68a04a343cad..2da29ac178fc 100644 --- a/include/linux/seq_file.h +++ b/include/linux/seq_file.h @@ -123,6 +123,7 @@ static inline int seq_nodemask_list(struct seq_file *m, nodemask_t *mask) } 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); |