| Message ID | 20241216083248.1816638-1-arnd@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | btrfs: avoid opencoded 64-bit div/mod operation | expand |
在 2024/12/16 19:02, Arnd Bergmann 写道: > From: Arnd Bergmann <arnd@arndb.de> > > Dividing 64-bit numbers causes a link failure on 32-bit builds: > > arm-linux-gnueabi-ld: fs/btrfs/sysfs.o: in function `btrfs_read_policy_store': > sysfs.c:(.text+0x3ce0): undefined reference to `__aeabi_ldivmod' > > Use an explicit call to div_u64_rem() here to work around this. It would > be possible to optimize this further, but this is not a performance > critical operation. > > Fixes: 185fa5c7ac5a ("btrfs: introduce RAID1 round-robin read balancing") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > fs/btrfs/sysfs.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c > index 50bc4b6cb821..67bc8fa4d6ab 100644 > --- a/fs/btrfs/sysfs.c > +++ b/fs/btrfs/sysfs.c > @@ -1433,7 +1433,9 @@ static ssize_t btrfs_read_policy_store(struct kobject *kobj, > #ifdef CONFIG_BTRFS_EXPERIMENTAL > if (index == BTRFS_READ_POLICY_RR) { > if (value != -1) { > - if ((value % fs_devices->fs_info->sectorsize) != 0) { > + u32 rem; > + div_u64_rem(value, fs_devices->fs_info->sectorsize, &rem); The original check is already bad, it's just a IS_ALIGNED(). So a much simpler solution is: + if (!IS_ALIGNED(value, fs_info->sectorsize)) { Thanks, Qu > + if (rem) { > btrfs_err(fs_devices->fs_info, > "read_policy: min_contiguous_read %lld should be multiples of the sectorsize %u", > value, fs_devices->fs_info->sectorsize);
>> @@ -1433,7 +1433,9 @@ static ssize_t btrfs_read_policy_store(struct >> kobject *kobj, >> #ifdef CONFIG_BTRFS_EXPERIMENTAL >> if (index == BTRFS_READ_POLICY_RR) { >> if (value != -1) { >> - if ((value % fs_devices->fs_info->sectorsize) != 0) { >> + u32 rem; >> + div_u64_rem(value, fs_devices->fs_info->sectorsize, &rem); > > The original check is already bad, it's just a IS_ALIGNED(). > > So a much simpler solution is: > > + if (!IS_ALIGNED(value, fs_info->sectorsize)) { Right, this was also in the review comment by David, and the change is already in the local work-space. I will be sending v4 out. Currently dealing with some rebase issues. Thanks, Anand
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 50bc4b6cb821..67bc8fa4d6ab 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -1433,7 +1433,9 @@ static ssize_t btrfs_read_policy_store(struct kobject *kobj, #ifdef CONFIG_BTRFS_EXPERIMENTAL if (index == BTRFS_READ_POLICY_RR) { if (value != -1) { - if ((value % fs_devices->fs_info->sectorsize) != 0) { + u32 rem; + div_u64_rem(value, fs_devices->fs_info->sectorsize, &rem); + if (rem) { btrfs_err(fs_devices->fs_info, "read_policy: min_contiguous_read %lld should be multiples of the sectorsize %u", value, fs_devices->fs_info->sectorsize);