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