Linux-5.11 Patch

[meke]

The part_stat_read function has changed in Linux-5.11, so I made a patch for it.

I am not sure about it, so please review it.

[akiradeveloper]

Here is the compile error message with 2.2.13 and 5.11. With 5.10, it was ok.

/home/akira/dm-writeboost/src/dm-writeboost-daemon.c: In function ‘writeback_modulator_proc’:
/home/akira/dm-writeboost/src/dm-writeboost-daemon.c:484:48: error: ‘struct block_device’ has no member named ‘bd_part’; did you mean ‘bd_partno’?
  struct hd_struct *hd = wb->backing_dev->bdev->bd_part;
                                                ^~~~~~~
                                                bd_partno
In file included from /home/akira/dm-writeboost/src/dm-writeboost-daemon.c:25:
./include/linux/part_stat.h:35:15: error: dereferencing pointer to incomplete type ‘struct hd_struct’
  typeof((part)->bd_stats->field) res = 0;   \
               ^~
/home/akira/dm-writeboost/src/dm-writeboost-daemon.c:489:26: note: in expansion of macro ‘part_stat_read’
   new = jiffies_to_msecs(part_stat_read(hd, io_ticks));
                          ^~~~~~~~~~~~~~
make[2]: *** [scripts/Makefile.build:279: /home/akira/dm-writeboost/src/dm-writeboost-daemon.o] Error 1
make[1]: *** [Makefile:1800: /home/akira/dm-writeboost/src] Error 2
make[1]: Leaving directory '/home/akira/linux'
make: *** [Makefile:11: all] Error 2

[akiradeveloper]

Confirmed that the patch fixes the compile error.

[akiradeveloper]

Let's look at a code in a main tree. (drivers/nvme/target/admin-cmd.c)

5.10

    xa_for_each(&ctrl->subsys->namespaces, idx, ns) {
        /* we don't have the right data for file backed ns */
        if (!ns->bdev)
            continue;
        host_reads += part_stat_read(ns->bdev->bd_part, ios[READ]);

5.11

    xa_for_each(&ctrl->subsys->namespaces, idx, ns) {
        /* we don't have the right data for file backed ns */
        if (!ns->bdev)
            continue;
        host_reads += part_stat_read(ns->bdev, ios[READ]);

[akiradeveloper]

@meke I will drop this one because piso77 has submitted a complete PR. I expected you to update the patch quickly so I can approve it.