// Block I/O tapset
// Copyright (C) 2006 Intel Corp.
// Copyright (C) 2006 IBM Corp.
//
// This file is part of systemtap, and is free software.  You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.

%{
#include <linux/bio.h>
#include <linux/genhd.h>
%}

/* get i-node number of mapped file */
function __bio_ino:long(bio:long)
%{ /* pure */
    struct bio *bio = (struct bio *)(long)THIS->bio;
    struct page *bv_page = bio? kread(&(bio->bi_io_vec[0].bv_page)) : NULL;
    struct address_space *mapping;
    struct inode *host;
    THIS->__retvalue = -1;
    if (bv_page && !PageSlab(bv_page) && !PageSwapCache(bv_page)) {
        mapping = kread(&(bv_page->mapping));
        if (mapping && ((unsigned long)mapping & PAGE_MAPPING_ANON) == 0) {
            host = kread(&(mapping->host));
            if (host)
                THIS->__retvalue = kread(&(host->i_ino));
        }
    }
    CATCH_DEREF_FAULT();
%}

/* returns 0 for read, 1 for write */
function bio_rw_num:long(rw:long)
%{ /* pure */
    long rw = (long)THIS->rw;
    THIS->__retvalue = (rw & (1 << BIO_RW));
%}

/* returns R for read, W for write */
function bio_rw_str(rw)
{
    return bio_rw_num(rw) == BIO_READ ? "R" : "W"
}

/* returns start sector */
function __bio_start_sect:long(bio:long)
%{ /* pure */
    struct bio *bio = (struct bio *)(long)THIS->bio;
    struct block_device *bi_bdev = bio? kread(&(bio->bi_bdev)) : NULL;
    struct hd_struct *bd_part = bi_bdev? kread(&(bi_bdev->bd_part)) : NULL;
    if (bd_part == NULL)
        THIS->__retvalue = -1;
    else
        THIS->__retvalue = kread(&(bd_part->start_sect));
    CATCH_DEREF_FAULT();
%}

/* returns the block device name */
function __bio_devname:string(bio:long)
%{ /* pure */
    char b[BDEVNAME_SIZE];
    struct bio *bio = (struct bio *)(long)THIS->bio;
    struct block_device *bdev = kread(&(bio->bi_bdev));
	if (bdev == NULL) {
		strlcpy(THIS->__retvalue, "N/A", MAXSTRINGLEN);
	} else {
		const char *name = bdevname(bdev, b); /* FIXME: deref hazard! */
		deref_string(THIS->__retvalue, name, MAXSTRINGLEN);
	}
	CATCH_DEREF_FAULT();
%}

global BIO_READ = 0, BIO_WRITE = 1


/* probe ioblock.request
 *
 *  Fires whenever making a generic block I/O request.
 *
 * Context:
 *  The process makes block I/O request
 *
 * Variables:
 *  devname   - block device name
 *  ino       - i-node number of the mapped file 
 *  sector    - beginning sector for the entire bio 
 *  flags     - see below 
 *  	BIO_UPTODATE    0       ok after I/O completion
 *  	BIO_RW_BLOCK    1       RW_AHEAD set, and read/write would block
 *  	BIO_EOF         2       out-out-bounds error
 *  	BIO_SEG_VALID   3       nr_hw_seg valid 
 *  	BIO_CLONED      4       doesn't own data
 *  	BIO_BOUNCED     5       bio is a bounce bio
 *  	BIO_USER_MAPPED 6       contains user pages
 *  	BIO_EOPNOTSUPP  7       not supported
 *  
 *  rw        - binary trace for read/write request
 *  vcnt      - bio vector count which represents number of array element (page, 
 *              offset, length) which make up this I/O request
 *  idx       - offset into the bio vector array
 *  phys_segments - number of segments in this bio after physical address
 *                  coalescing is performed.  
 *  hw_segments -   number of segments after physical and DMA remapping
 *              hardware coalescing is performed
 *  size      - total size in bytes 
 *  bdev      - target block device
 *  bdev_contains - points to the device object which contains the
 *                  partition (when bio structure represents a partition)
 *  p_start_sect -  points to the start sector of the partition
 *                  structure of the device
 */
probe ioblock.request = kernel.function ("generic_make_request")
{
        devname = __bio_devname($bio)
        ino = __bio_ino($bio)

        sector = $bio->bi_sector
        flags = $bio->bi_flags
        rw = $bio->bi_rw
        vcnt = $bio->bi_vcnt
        idx = $bio->bi_idx
        phys_segments = $bio->bi_phys_segments
        hw_segments = $bio->bi_hw_segments
        size = $bio->bi_size

        bdev = $bio->bi_bdev
        bdev_contains = $bio->bi_bdev->bd_contains
        p_start_sect = __bio_start_sect($bio)
}

/* probe ioblock.end
 *
 *  Fires whenever a block I/O transfer is complete.
 *
 * Context:
 *  The process signals the transfer is done.
 *
 * Variables:
 *  devname   - block device name
 *  ino       - i-node number of the mapped file
 *  byte_done - number of bytes transferred 
 *  sector    - beginning sector for the entire bio
 *  flags     - see below
 *      BIO_UPTODATE    0       ok after I/O completion
 *      BIO_RW_BLOCK    1       RW_AHEAD set, and read/write would block
 *      BIO_EOF         2       out-out-bounds error
 *      BIO_SEG_VALID   3       nr_hw_seg valid
 *      BIO_CLONED      4       doesn't own data
 *      BIO_BOUNCED     5       bio is a bounce bio
 *      BIO_USER_MAPPED 6       contains user pages
 *      BIO_EOPNOTSUPP  7       not supported
 *  error     - 0 on success
 *  rw        - binary trace for read/write request 
 *  vcnt      - bio vector count which represents number of array element (page,
 *              offset, length) which makes up this I/O request
 *  idx       - offset into the bio vector array
 *  phys_segments - number of segments in this bio after physical address
 *                  coalescing is performed.
 *  hw_segments -   number of segments after physical and DMA remapping
 *              hardware coalescing is performed
 *  size      - total size in bytes 
 */
probe ioblock.end = kernel.function("bio_endio")
{
        devname = __bio_devname($bio)
        ino = __bio_ino($bio)

        bytes_done = $bytes_done
        error = $error

        sector = $bio->bi_sector
        flags = $bio->bi_flags
        rw = $bio->bi_rw
        vcnt = $bio->bi_vcnt
        idx = $bio->bi_idx
        phys_segments = $bio->bi_phys_segments
        hw_segments = $bio->bi_hw_segments
        size = $bio->bi_size
}