Instead of walking the page array just walk the kernel virtual
address in ->b_addr. This prepares for using vmalloc for buffers
and removing the b_pages array.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/xfs/xfs_buf.c | 93 ++++++++++++++----------------------------------
fs/xfs/xfs_buf.h | 2 --
2 files changed, 26 insertions(+), 69 deletions(-)
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 1bfd89dbb78d79..ddd917bed22e34 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -343,7 +343,6 @@ xfs_buf_alloc_kmem(
bp->b_addr = NULL;
return -ENOMEM;
}
- bp->b_offset = offset_in_page(bp->b_addr);
bp->b_pages = bp->b_page_array;
bp->b_pages[0] = kmem_to_page(bp->b_addr);
bp->b_page_count = 1;
@@ -1426,79 +1425,47 @@ 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 page_index;
- unsigned int total_nr_pages = bp->b_page_count;
- int nr_pages;
struct bio *bio;
- sector_t sector = bp->b_maps[map].bm_bn;
int size;
- int offset;
-
- /* skip the pages in the buffer before the start offset */
- page_index = 0;
- offset = *buf_offset;
- while (offset >= PAGE_SIZE) {
- page_index++;
- offset -= PAGE_SIZE;
- }
/*
* 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;
+ size = min_t(unsigned int, BBTOB(bp->b_maps[map].bm_len),
+ BBTOB(bp->b_length) - *buf_offset);
+ if (WARN_ON_ONCE(bp->b_page_count > BIO_MAX_VECS)) {
+ xfs_buf_ioerror(bp, -EIO);
+ return;
+ }
-next_chunk:
atomic_inc(&bp->b_io_remaining);
- nr_pages = bio_max_segs(total_nr_pages);
- bio = bio_alloc(bp->b_target->bt_bdev, nr_pages, op, GFP_NOIO);
- bio->bi_iter.bi_sector = sector;
+ bio = bio_alloc(bp->b_target->bt_bdev, bp->b_page_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_pages; nr_pages--, page_index++) {
- int rbytes, nbytes = PAGE_SIZE - offset;
+ do {
+ void *data = bp->b_addr + *buf_offset;
+ struct page *page = kmem_to_page(data);
+ unsigned int off = offset_in_page(data);
+ unsigned int len = min_t(unsigned, size, PAGE_SIZE - off);
- if (nbytes > size)
- nbytes = size;
+ __bio_add_page(bio, page, len, off);
+ size -= len;
+ *buf_offset += len;
+ } while (size);
- rbytes = bio_add_page(bio, bp->b_pages[page_index], nbytes,
- offset);
- if (rbytes < nbytes)
- break;
-
- offset = 0;
- sector += BTOBB(nbytes);
- size -= nbytes;
- total_nr_pages--;
+ if (xfs_buf_is_vmapped(bp)) {
+ flush_kernel_vmap_range(bp->b_addr,
+ xfs_buf_vmap_len(bp));
}
-
- 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);
- }
-
+ submit_bio(bio);
}
STATIC void
@@ -1507,8 +1474,7 @@ _xfs_buf_ioapply(
{
struct blk_plug plug;
blk_opf_t op;
- int offset;
- int size;
+ unsigned int offset = 0;
int i;
/*
@@ -1564,16 +1530,9 @@ _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 379d58c4cb9a27..2116fed2b53026 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -186,8 +186,6 @@ struct xfs_buf {
atomic_t b_pin_count; /* pin count */
atomic_t b_io_remaining; /* #outstanding I/O requests */
unsigned int b_page_count; /* size of page array */
- unsigned int b_offset; /* page offset of b_addr,
- only for _XBF_KMEM buffers */
int b_error; /* error code on I/O */
/*
--
2.39.2
