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Commit ad147d01 authored by David Howells's avatar David Howells Committed by Al Viro
Browse files

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



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: default avatarDavid Howells <dhowells@redhat.com>
parent f805442e

fs/proc/generic.c

+47 −51
Original line number Diff line number Diff line
@@ -71,9 +71,10 @@ __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

		if (!dp->read_proc)

			break;



		/* How to be a proc read function

		 * ------------------------------

		 * Prototype:

		 *    int f(char *buffer, char **start, off_t offset,
@@ -81,48 +82,43 @@ __proc_file_read(struct file *file, char __user *buf, size_t nbytes, 
		 *

		 * Assume that the buffer is "count" bytes in size.

		 *

			 * If you know you have supplied all the data you

			 * have, set *peof.

		 * 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.

		 *

		 * 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

		 *

		 * 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

			break;

		n = dp->read_proc(page, &start, *ppos, count, &eof, dp->data);



		if (n == 0)   /* end of file */

			break;