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procfs: Clean up huge if-statement in __proc_file_read()

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Switch huge if-statement in __proc_file_read() around.  This then puts the
single line loop break immediately after the if-statement and allows us to
de-indent the huge comment and make it take fewer lines.  The code following
the if-statement then follows naturally from the call to dp->read_proc().

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2013-04-04 16:32:28 +01:00 committed by Al Viro
parent f805442e13
commit ad147d011f
1 changed files with 47 additions and 51 deletions
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98
fs/proc/generic.c
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@ -71,59 +71,55 @@ __proc_file_read(struct file *file, char __user *buf, size_t nbytes,
count = min_t(size_t, PROC_BLOCK_SIZE, nbytes);
start = NULL;
if (dp->read_proc) {
/*
* How to be a proc read function
* ------------------------------
* Prototype:
* int f(char *buffer, char **start, off_t offset,
* int count, int *peof, void *dat)
*
* Assume that the buffer is "count" bytes in size.
*
* If you know you have supplied all the data you
* have, set *peof.
*
* You have three ways to return data:
* 0) Leave *start = NULL. (This is the default.)
* Put the data of the requested offset at that
* offset within the buffer. Return the number (n)
* of bytes there are from the beginning of the
* buffer up to the last byte of data. If the
* number of supplied bytes (= n - offset) is
* greater than zero and you didn't signal eof
* and the reader is prepared to take more data
* you will be called again with the requested
* offset advanced by the number of bytes
* absorbed. This interface is useful for files
* no larger than the buffer.
* 1) Set *start = an unsigned long value less than
* the buffer address but greater than zero.
* Put the data of the requested offset at the
* beginning of the buffer. Return the number of
* bytes of data placed there. If this number is
* greater than zero and you didn't signal eof
* and the reader is prepared to take more data
* you will be called again with the requested
* offset advanced by *start. This interface is
* useful when you have a large file consisting
* of a series of blocks which you want to count
* and return as wholes.
* (Hack by Paul.Russell@rustcorp.com.au)
* 2) Set *start = an address within the buffer.
* Put the data of the requested offset at *start.
* Return the number of bytes of data placed there.
* If this number is greater than zero and you
* didn't signal eof and the reader is prepared to
* take more data you will be called again with the
* requested offset advanced by the number of bytes
* absorbed.
*/
n = dp->read_proc(page, &start, *ppos,
count, &eof, dp->data);
} else
if (!dp->read_proc)
break;
/* How to be a proc read function
* ------------------------------
* Prototype:
* int f(char *buffer, char **start, off_t offset,
* int count, int *peof, void *dat)
*
* Assume that the buffer is "count" bytes in size.
*
* If you know you have supplied all the data you have, set
* *peof.
*
* You have three ways to return data:
*
* 0) Leave *start = NULL. (This is the default.) Put the
* data of the requested offset at that offset within the
* buffer. Return the number (n) of bytes there are from
* the beginning of the buffer up to the last byte of data.
* If the number of supplied bytes (= n - offset) is greater
* than zero and you didn't signal eof and the reader is
* prepared to take more data you will be called again with
* the requested offset advanced by the number of bytes
* absorbed. This interface is useful for files no larger
* than the buffer.
*
* 1) Set *start = an unsigned long value less than the buffer
* address but greater than zero. Put the data of the
* requested offset at the beginning of the buffer. Return
* the number of bytes of data placed there. If this number
* is greater than zero and you didn't signal eof and the
* reader is prepared to take more data you will be called
* again with the requested offset advanced by *start. This
* interface is useful when you have a large file consisting
* of a series of blocks which you want to count and return
* as wholes.
* (Hack by Paul.Russell@rustcorp.com.au)
*
* 2) Set *start = an address within the buffer. Put the data
* of the requested offset at *start. Return the number of
* bytes of data placed there. If this number is greater
* than zero and you didn't signal eof and the reader is
* prepared to take more data you will be called again with
* the requested offset advanced by the number of bytes
* absorbed.
*/
n = dp->read_proc(page, &start, *ppos, count, &eof, dp->data);
if (n == 0) /* end of file */
break;
if (n < 0) { /* error */