projects / mirror_zfs.git / blame
| Commit | Line | Data |
|---|---|---|
| 2404b014 BB |
1 | dnl # |
| 2 | dnl # 2.6.30 API change | |
| 3 | dnl # | |
| 4 | dnl # The bdev_physical_block_size() interface was added to provide a way | |
| 5 | dnl # to determine the smallest write which can be performed without a | |
| 6 | dnl # read-modify-write operation. From the kernel documentation: | |
| 7 | dnl # | |
| 8 | dnl # What: /sys/block/<disk>/queue/physical_block_size | |
| 9 | dnl # Date: May 2009 | |
| 10 | dnl # Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 11 | dnl # Description: | |
| 12 | dnl # This is the smallest unit the storage device can write | |
| 13 | dnl # without resorting to read-modify-write operation. It is | |
| 14 | dnl # usually the same as the logical block size but may be | |
| 15 | dnl # bigger. One example is SATA drives with 4KB sectors | |
| 16 | dnl # that expose a 512-byte logical block size to the | |
| 17 | dnl # operating system. | |
| 18 | dnl # | |
| 19 | dnl # Unfortunately, this interface isn't entirely reliable because | |
| 20 | dnl # drives are sometimes known to misreport this value. | |
| 21 | dnl # | |
| 22 | AC_DEFUN([ZFS_AC_KERNEL_BDEV_PHYSICAL_BLOCK_SIZE], [ | |
| 23 | AC_MSG_CHECKING([whether bdev_physical_block_size() is available]) | |
| 24 | tmp_flags="$EXTRA_KCFLAGS" | |
| e191b54e | 25 | EXTRA_KCFLAGS="${NO_UNUSED_BUT_SET_VARIABLE}" |
| 2404b014 BB |
26 | ZFS_LINUX_TRY_COMPILE([ |
| 27 | #include <linux/blkdev.h> | |
| 28 | ],[ | |
| 29 | struct block_device *bdev = NULL; | |
| 30 | bdev_physical_block_size(bdev); | |
| 31 | ],[ | |
| 32 | AC_MSG_RESULT(yes) | |
| 33 | AC_DEFINE(HAVE_BDEV_PHYSICAL_BLOCK_SIZE, 1, | |
| 34 | [bdev_physical_block_size() is available]) | |
| 35 | ],[ | |
| 36 | AC_MSG_RESULT(no) | |
| 37 | ]) | |
| 38 | EXTRA_KCFLAGS="$tmp_flags" | |
| 39 | ]) |