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author | Al Viro <viro@zeniv.linux.org.uk> | 2014-11-19 18:02:53 (GMT) |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2014-11-19 18:02:53 (GMT) |
commit | 8ce74dd6057832618957fc2cbd38fa959c3a0a6c (patch) | |
tree | af3bede951087ebc58988ad073182a85bf899e27 /Documentation | |
parent | 78d28e651f97866d608d9b41f8ad291e65d47dd5 (diff) | |
parent | 9761536e1d9e9e1f325fb04d4ad46b15a39eb94a (diff) | |
download | linux-8ce74dd6057832618957fc2cbd38fa959c3a0a6c.tar.xz |
Merge tag 'trace-seq-file-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into for-next
Pull the beginning of seq_file cleanup from Steven:
"I'm looking to clean up the seq_file code and to eventually merge the
trace_seq code with seq_file as well, since they basically do the same thing.
Part of this process is to remove the return code of seq_printf() and friends
as they are rather inconsistent. It is better to use the new function
seq_has_overflowed() if you want to stop processing when the buffer
is full. Note, if the buffer is full, the seq_file code will throw away
the contents, allocate a bigger buffer, and then call your code again
to fill in the data. The only thing that breaking out of the function
early does is to save a little time which is probably never noticed.
I started with patches from Joe Perches and modified them as well.
There's many more places that need to be updated before we can convert
seq_printf() and friends to return void. But this patch set introduces
the seq_has_overflowed() and does some initial updates."
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/filesystems/debugfs.txt | 2 | ||||
-rw-r--r-- | Documentation/filesystems/seq_file.txt | 22 | ||||
-rw-r--r-- | Documentation/filesystems/vfs.txt | 2 |
3 files changed, 15 insertions, 11 deletions
diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt index 3a863f6..88ab81c 100644 --- a/Documentation/filesystems/debugfs.txt +++ b/Documentation/filesystems/debugfs.txt @@ -140,7 +140,7 @@ file. struct dentry *parent, struct debugfs_regset32 *regset); - int debugfs_print_regs32(struct seq_file *s, struct debugfs_reg32 *regs, + void debugfs_print_regs32(struct seq_file *s, struct debugfs_reg32 *regs, int nregs, void __iomem *base, char *prefix); The "base" argument may be 0, but you may want to build the reg32 array diff --git a/Documentation/filesystems/seq_file.txt b/Documentation/filesystems/seq_file.txt index 8ea3e90..b797ed3 100644 --- a/Documentation/filesystems/seq_file.txt +++ b/Documentation/filesystems/seq_file.txt @@ -180,23 +180,19 @@ output must be passed to the seq_file code. Some utility functions have been defined which make this task easy. Most code will simply use seq_printf(), which works pretty much like -printk(), but which requires the seq_file pointer as an argument. It is -common to ignore the return value from seq_printf(), but a function -producing complicated output may want to check that value and quit if -something non-zero is returned; an error return means that the seq_file -buffer has been filled and further output will be discarded. +printk(), but which requires the seq_file pointer as an argument. For straight character output, the following functions may be used: - int seq_putc(struct seq_file *m, char c); - int seq_puts(struct seq_file *m, const char *s); - int seq_escape(struct seq_file *m, const char *s, const char *esc); + seq_putc(struct seq_file *m, char c); + seq_puts(struct seq_file *m, const char *s); + seq_escape(struct seq_file *m, const char *s, const char *esc); The first two output a single character and a string, just like one would expect. seq_escape() is like seq_puts(), except that any character in s which is in the string esc will be represented in octal form in the output. -There is also a pair of functions for printing filenames: +There are also a pair of functions for printing filenames: int seq_path(struct seq_file *m, struct path *path, char *esc); int seq_path_root(struct seq_file *m, struct path *path, @@ -209,6 +205,14 @@ root is desired, it can be used with seq_path_root(). Note that, if it turns out that path cannot be reached from root, the value of root will be changed in seq_file_root() to a root which *does* work. +A function producing complicated output may want to check + bool seq_has_overflowed(struct seq_file *m); +and avoid further seq_<output> calls if true is returned. + +A true return from seq_has_overflowed means that the seq_file buffer will +be discarded and the seq_show function will attempt to allocate a larger +buffer and retry printing. + Making it all work diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 20bf204..43ce050 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -835,7 +835,7 @@ struct file_operations { ssize_t (*splice_read)(struct file *, struct pipe_inode_info *, size_t, unsigned int); int (*setlease)(struct file *, long arg, struct file_lock **, void **); long (*fallocate)(struct file *, int mode, loff_t offset, loff_t len); - int (*show_fdinfo)(struct seq_file *m, struct file *f); + void (*show_fdinfo)(struct seq_file *m, struct file *f); }; Again, all methods are called without any locks being held, unless |