This patch introduces a count parameter to exfat_get_cluster, which
serves as an input parameter for the caller to specify the desired
number of clusters, and as an output parameter to store the length
of consecutive clusters.
This patch can improve read performance by reducing the number of
get_block calls in sequential read scenarios. speacially in small
cluster size.
According to my test data, the performance improvement is
approximately 10% when read FAT_CHAIN file with 512 bytes of
cluster size.
454 MB/s -> 511 MB/s
Suggested-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Change exfat_cache_lookup to return the cluster number of the last
cluster before the next cache (i.e., the end of the current cache range)
or the given 'end' if there is no next cache. This allows the caller to
know whether the next cluster after the current cache is cached.
The function signature is changed to accept an 'end' parameter, which
is the upper bound of the search range. The function now stops early
if it finds a cache that starts within the current cache's tail, meaning
caches are contiguous. The return value is the cluster number at which
the next cache starts (minus one) or the original 'end' if no next cache
is found.
The new behavior is illustrated as follows:
cache: [ccccccc-------ccccccccc]
search: [..................]
return: ^
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
The current cache mechanism does not support reading clusters starting
from a file offset of zero. This patch enables that feature in
preparation for subsequent reads of contiguous clusters from offset zero.
1. support finding clusters with zero offset.
2. allow clusters with zero offset to be cached.
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Since exfat_ent_get supports cache buffer head, we can use this option to
reduce sb_bread calls when fetching consecutive entries.
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Remove parameter 'fclus' and 'allow_eof':
- The fclus parameter is changed to a local variable as it is not
needed to be returned.
- The passed allow_eof parameter was always 1, remove it and the
associated error handling.
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
The cache_id remains unchanged on a cache miss; its value is always
exactly what was set by cache_init. Therefore, checking this value
again is meaningless.
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
The infinite cluster chain loop check is not work because the
loop will terminate when fclus reaches the parameter cluster,
and the parameter cluster value is never greater than
ei->valid_size.
The following relationship holds:
'fclus' < 'cluster' ≤ ei->valid_size ≤ sb->num_clusters
The check would only be triggered if a cluster number greater than
sb->num_clusters is passed, but no caller currently does this.
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
This patch is part 2 of cached buffer head for exfat_ent_get,
it introduces an argument for exfat_ent_get, and make sure this
routine releases buffer head refcount when any error return.
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
asm/unaligned.h is always an include of asm-generic/unaligned.h;
might as well move that thing to linux/unaligned.h and include
that - there's nothing arch-specific in that header.
auto-generated by the following:
for i in `git grep -l -w asm/unaligned.h`; do
sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i
done
for i in `git grep -l -w asm-generic/unaligned.h`; do
sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i
done
git mv include/asm-generic/unaligned.h include/linux/unaligned.h
git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h
sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild
sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h
Yes, yes, I know the slab people were planning on going slow and letting
every subsystem fight this thing on their own. But let's just rip off
the band-aid and get it over and done with. I don't want to see a
number of unnecessary pull requests just to get rid of a flag that no
longer has any meaning.
This was mainly done with a couple of 'sed' scripts and then some manual
cleanup of the end result.
Link: https://lore.kernel.org/all/CAHk-=wji0u+OOtmAOD-5JV3SXcRJF___k_+8XNKmak0yd5vW1Q@mail.gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
