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gfs2: avoid inefficient use of crc32_le_shift()

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__get_log_header() was using crc32_le_shift() to update a CRC with four
zero bytes.  However, this is about 5x slower than just CRC'ing four
zero bytes in the normal way.  Just do that instead.

(We could instead make crc32_le_shift() faster on short lengths.  But
all its callers do just fine without it, so I'd like to just remove it.)

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
This commit is contained in:
Eric Biggers 2025-05-11 11:31:33 -07:00 committed by Andreas Gruenbacher
parent 87faee382d
commit b6ccde39b1
1 changed files with 2 additions and 1 deletions
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3
fs/gfs2/recovery.c
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@ -118,6 +118,7 @@ void gfs2_revoke_clean(struct gfs2_jdesc *jd)
int __get_log_header(struct gfs2_sbd *sdp, const struct gfs2_log_header *lh,
unsigned int blkno, struct gfs2_log_header_host *head)
{
const u32 zero = 0;
u32 hash, crc;
if (lh->lh_header.mh_magic != cpu_to_be32(GFS2_MAGIC) ||
@ -126,7 +127,7 @@ int __get_log_header(struct gfs2_sbd *sdp, const struct gfs2_log_header *lh,
return 1;
hash = crc32(~0, lh, LH_V1_SIZE - 4);
hash = ~crc32_le_shift(hash, 4); /* assume lh_hash is zero */
hash = ~crc32(hash, &zero, 4); /* assume lh_hash is zero */
if (be32_to_cpu(lh->lh_hash) != hash)
return 1;