From: Christoph Hellwig <hch@xxxxxx>
Instead of walking the folio array just walk the kernel virtual
address in ->b_addr. This prepares for using vmalloc for buffers
and removing the b_folio array.
[dchinner: ported to folios-based buffers.]
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
fs/xfs/xfs_buf.c | 110 +++++++++++++----------------------------------
fs/xfs/xfs_buf.h | 2 -
2 files changed, 29 insertions(+), 83 deletions(-)
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index a77e2d8c8107..303945554415 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -358,7 +358,6 @@ xfs_buf_alloc_kmem(
}
bp->b_folios = bp->b_folio_array;
bp->b_folios[0] = kmem_to_folio(bp->b_addr);
- bp->b_offset = offset_in_folio(bp->b_folios[0], bp->b_addr);
bp->b_folio_count = 1;
bp->b_flags |= _XBF_KMEM;
return 0;
@@ -1549,87 +1548,44 @@ xfs_buf_bio_end_io(
static void
xfs_buf_ioapply_map(
struct xfs_buf *bp,
- int map,
- int *buf_offset,
- int *count,
+ unsigned int map,
+ unsigned int *buf_offset,
blk_opf_t op)
{
- int folio_index;
- unsigned int total_nr_folios = bp->b_folio_count;
- int nr_folios;
struct bio *bio;
- sector_t sector = bp->b_maps[map].bm_bn;
int size;
- int offset;
- /*
- * If the start offset if larger than a single page, we need to be
- * careful. We might have a high order folio, in which case the indexing
- * is from the start of the buffer. However, if we have more than one
- * folio single page folio in the buffer, we need to skip the folios in
- * the buffer before the start offset.
- */
- folio_index = 0;
- offset = *buf_offset;
- if (bp->b_folio_count > 1) {
- while (offset >= PAGE_SIZE) {
- folio_index++;
- offset -= PAGE_SIZE;
- }
+ /* Limit the IO size to the length of the current vector. */
+ size = min_t(unsigned int, BBTOB(bp->b_maps[map].bm_len),
+ BBTOB(bp->b_length) - *buf_offset);
+
+ if (WARN_ON_ONCE(bp->b_folio_count > BIO_MAX_VECS)) {
+ xfs_buf_ioerror(bp, -EIO);
+ return;
}
- /*
- * Limit the IO size to the length of the current vector, and update the
- * remaining IO count for the next time around.
- */
- size = min_t(int, BBTOB(bp->b_maps[map].bm_len), *count);
- *count -= size;
- *buf_offset += size;
-
-next_chunk:
atomic_inc(&bp->b_io_remaining);
- nr_folios = bio_max_segs(total_nr_folios);
- bio = bio_alloc(bp->b_target->bt_bdev, nr_folios, op, GFP_NOIO);
- bio->bi_iter.bi_sector = sector;
+ bio = bio_alloc(bp->b_target->bt_bdev, bp->b_folio_count, op, GFP_NOIO);
+ bio->bi_iter.bi_sector = bp->b_maps[map].bm_bn;
bio->bi_end_io = xfs_buf_bio_end_io;
bio->bi_private = bp;
- for (; size && nr_folios; nr_folios--, folio_index++) {
- struct folio *folio = bp->b_folios[folio_index];
- int nbytes = folio_size(folio) - offset;
-
- if (nbytes > size)
- nbytes = size;
-
- if (!bio_add_folio(bio, folio, nbytes,
- offset_in_folio(folio, offset)))
- break;
-
- offset = 0;
- sector += BTOBB(nbytes);
- size -= nbytes;
- total_nr_folios--;
- }
-
- if (likely(bio->bi_iter.bi_size)) {
- if (xfs_buf_is_vmapped(bp)) {
- flush_kernel_vmap_range(bp->b_addr,
- xfs_buf_vmap_len(bp));
- }
- submit_bio(bio);
- if (size)
- goto next_chunk;
- } else {
- /*
- * This is guaranteed not to be the last io reference count
- * because the caller (xfs_buf_submit) holds a count itself.
- */
- atomic_dec(&bp->b_io_remaining);
- xfs_buf_ioerror(bp, -EIO);
- bio_put(bio);
- }
-
+ do {
+ void *data = bp->b_addr + *buf_offset;
+ struct folio *folio = kmem_to_folio(data);
+ unsigned int off = offset_in_folio(folio, data);
+ unsigned int len = min_t(unsigned int, size,
+ folio_size(folio) - off);
+
+ bio_add_folio_nofail(bio, folio, len, off);
+ size -= len;
+ *buf_offset += len;
+ } while (size);
+
+ if (xfs_buf_is_vmapped(bp))
+ flush_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));
+ submit_bio(bio);
}
STATIC void
@@ -1638,8 +1594,7 @@ _xfs_buf_ioapply(
{
struct blk_plug plug;
blk_opf_t op;
- int offset;
- int size;
+ unsigned int offset = 0;
int i;
/*
@@ -1701,16 +1656,9 @@ _xfs_buf_ioapply(
* _xfs_buf_ioapply_vec() will modify them appropriately for each
* subsequent call.
*/
- offset = bp->b_offset;
- size = BBTOB(bp->b_length);
blk_start_plug(&plug);
- for (i = 0; i < bp->b_map_count; i++) {
- xfs_buf_ioapply_map(bp, i, &offset, &size, op);
- if (bp->b_error)
- break;
- if (size <= 0)
- break; /* all done */
- }
+ for (i = 0; i < bp->b_map_count; i++)
+ xfs_buf_ioapply_map(bp, i, &offset, op);
blk_finish_plug(&plug);
}
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index aef7015cf9f3..4d515407713b 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -198,8 +198,6 @@ struct xfs_buf {
atomic_t b_pin_count; /* pin count */
atomic_t b_io_remaining; /* #outstanding I/O requests */
unsigned int b_folio_count; /* size of folio array */
- unsigned int b_offset; /* page offset of b_addr,
- only for _XBF_KMEM buffers */
int b_error; /* error code on I/O */
/*
--
2.43.0
