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author | Al Viro <viro@zeniv.linux.org.uk> | 2013-03-31 17:43:23 (GMT) |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-04-09 18:13:29 (GMT) |
commit | 2043f495c7c1a06f7748b5bcd17656d93c95e1a6 (patch) | |
tree | f3d0368632a1fda88bb385ddfc01600fe450e74f /fs | |
parent | 70ef457dc92bdd03c0c8d640fce45909166983a1 (diff) | |
download | linux-2043f495c7c1a06f7748b5bcd17656d93c95e1a6.tar.xz |
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>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/seq_file.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/fs/seq_file.c b/fs/seq_file.c index 38bb59f..774c1eb 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; |