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xfs: buffer items don't straddle pages anymore

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Unmapped buffers don't exist anymore, so the page straddling
detection and slow path code can go away now.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
This commit is contained in:
Dave Chinner 2025-03-10 14:19:12 +01:00 committed by Carlos Maiolino
parent a2f790b285
commit fd87851680
1 changed files with 0 additions and 124 deletions
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124
fs/xfs/xfs_buf_item.c
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@ -57,31 +57,6 @@ xfs_buf_log_format_size(
(blfp->blf_map_size * sizeof(blfp->blf_data_map[0]));
}
/*
* We only have to worry about discontiguous buffer range straddling on unmapped
* buffers. Everything else will have a contiguous data region we can copy from.
*/
static inline bool
xfs_buf_item_straddle(
struct xfs_buf *bp,
uint offset,
int first_bit,
int nbits)
{
void *first, *last;
if (bp->b_page_count == 1)
return false;
first = xfs_buf_offset(bp, offset + (first_bit << XFS_BLF_SHIFT));
last = xfs_buf_offset(bp,
offset + ((first_bit + nbits) << XFS_BLF_SHIFT));
if (last - first != nbits * XFS_BLF_CHUNK)
return true;
return false;
}
/*
* Return the number of log iovecs and space needed to log the given buf log
* item segment.
@ -98,11 +73,8 @@ xfs_buf_item_size_segment(
int *nvecs,
int *nbytes)
{
struct xfs_buf *bp = bip->bli_buf;
int first_bit;
int nbits;
int next_bit;
int last_bit;
first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0);
if (first_bit == -1)
@ -115,15 +87,6 @@ xfs_buf_item_size_segment(
nbits = xfs_contig_bits(blfp->blf_data_map,
blfp->blf_map_size, first_bit);
ASSERT(nbits > 0);
/*
* Straddling a page is rare because we don't log contiguous
* chunks of unmapped buffers anywhere.
*/
if (nbits > 1 &&
xfs_buf_item_straddle(bp, offset, first_bit, nbits))
goto slow_scan;
(*nvecs)++;
*nbytes += nbits * XFS_BLF_CHUNK;
@ -138,43 +101,6 @@ xfs_buf_item_size_segment(
} while (first_bit != -1);
return;
slow_scan:
ASSERT(bp->b_addr == NULL);
last_bit = first_bit;
nbits = 1;
while (last_bit != -1) {
*nbytes += XFS_BLF_CHUNK;
/*
* This takes the bit number to start looking from and
* returns the next set bit from there. It returns -1
* if there are no more bits set or the start bit is
* beyond the end of the bitmap.
*/
next_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
last_bit + 1);
/*
* If we run out of bits, leave the loop,
* else if we find a new set of bits bump the number of vecs,
* else keep scanning the current set of bits.
*/
if (next_bit == -1) {
if (first_bit != last_bit)
(*nvecs)++;
break;
} else if (next_bit != last_bit + 1 ||
xfs_buf_item_straddle(bp, offset, first_bit, nbits)) {
last_bit = next_bit;
first_bit = next_bit;
(*nvecs)++;
nbits = 1;
} else {
last_bit++;
nbits++;
}
}
}
/*
@ -287,8 +213,6 @@ xfs_buf_item_format_segment(
struct xfs_buf *bp = bip->bli_buf;
uint base_size;
int first_bit;
int last_bit;
int next_bit;
uint nbits;
/* copy the flags across from the base format item */
@ -333,15 +257,6 @@ xfs_buf_item_format_segment(
nbits = xfs_contig_bits(blfp->blf_data_map,
blfp->blf_map_size, first_bit);
ASSERT(nbits > 0);
/*
* Straddling a page is rare because we don't log contiguous
* chunks of unmapped buffers anywhere.
*/
if (nbits > 1 &&
xfs_buf_item_straddle(bp, offset, first_bit, nbits))
goto slow_scan;
xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
first_bit, nbits);
blfp->blf_size++;
@ -357,45 +272,6 @@ xfs_buf_item_format_segment(
} while (first_bit != -1);
return;
slow_scan:
ASSERT(bp->b_addr == NULL);
last_bit = first_bit;
nbits = 1;
for (;;) {
/*
* This takes the bit number to start looking from and
* returns the next set bit from there. It returns -1
* if there are no more bits set or the start bit is
* beyond the end of the bitmap.
*/
next_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
(uint)last_bit + 1);
/*
* If we run out of bits fill in the last iovec and get out of
* the loop. Else if we start a new set of bits then fill in
* the iovec for the series we were looking at and start
* counting the bits in the new one. Else we're still in the
* same set of bits so just keep counting and scanning.
*/
if (next_bit == -1) {
xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
first_bit, nbits);
blfp->blf_size++;
break;
} else if (next_bit != last_bit + 1 ||
xfs_buf_item_straddle(bp, offset, first_bit, nbits)) {
xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
first_bit, nbits);
blfp->blf_size++;
first_bit = next_bit;
last_bit = next_bit;
nbits = 1;
} else {
last_bit++;
nbits++;
}
}
}
/*