On Thu, 15 Oct 2026, [email protected] wrote:
> From: Frank Li <[email protected]>
>
> Remove the dependency on the async_tx framework from dm-integrity's
> xor_journal() function. The async_xor() + async_tx_issue_pending_all()
> pattern is replaced with direct kmap_local_page() + memcpy() +
> crypto_xor() + kunmap_local() per page, which is simpler and removes
> the need for #include <linux/async_tx.h>.
>
> async_tx adds significant complexity and maintenance overhead while
> providing little practical benefit on modern systems, where RAID parity
> computation is typically performed more efficiently by CPU-based XOR/PQ
> implementations than by DMA engine offload.
>
> Signed-off-by: Frank Li <[email protected]>
Reviewed-by: Mikulas Patocka <[email protected]>
> ---
> drivers/md/dm-integrity.c | 26 ++++++++++++++------------
> 1 file changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
> index 802b377613b06..6bd0623b6402a 100644
> --- a/drivers/md/dm-integrity.c
> +++ b/drivers/md/dm-integrity.c
> @@ -23,7 +23,6 @@
> #include <crypto/hash.h>
> #include <crypto/skcipher.h>
> #include <crypto/utils.h>
> -#include <linux/async_tx.h>
> #include <linux/dm-bufio.h>
>
> #include "dm-audit.h"
> @@ -896,7 +895,6 @@ static void complete_journal_op(void *context)
> static void xor_journal(struct dm_integrity_c *ic, bool encrypt, unsigned
> int section,
> unsigned int n_sections, struct journal_completion
> *comp)
> {
> - struct async_submit_ctl submit;
> size_t n_bytes = (size_t)(n_sections * ic->journal_section_sectors) <<
> SECTOR_SHIFT;
> unsigned int pl_index, pl_offset, section_index;
> struct page_list *source_pl, *target_pl;
> @@ -913,14 +911,11 @@ static void xor_journal(struct dm_integrity_c *ic, bool
> encrypt, unsigned int se
>
> atomic_add(roundup(pl_offset + n_bytes, PAGE_SIZE) >> PAGE_SHIFT,
> &comp->in_flight);
>
> - init_async_submit(&submit, ASYNC_TX_XOR_ZERO_DST, NULL,
> complete_journal_op, comp, NULL);
> -
> section_index = pl_index;
>
> do {
> size_t this_step;
> - struct page *src_pages[2];
> - struct page *dst_page;
> + void *src0, *src1, *dst;
>
> while (unlikely(pl_index == section_index)) {
> unsigned int dummy;
> @@ -935,11 +930,20 @@ static void xor_journal(struct dm_integrity_c *ic, bool
> encrypt, unsigned int se
> }
>
> this_step = min(n_bytes, (size_t)PAGE_SIZE - pl_offset);
> - dst_page = target_pl[pl_index].page;
> - src_pages[0] = source_pl[pl_index].page;
> - src_pages[1] = ic->journal_xor[pl_index].page;
>
> - async_xor(dst_page, src_pages, pl_offset, 2, this_step,
> &submit);
> + src0 = kmap_local_page(source_pl[pl_index].page);
> + src1 = kmap_local_page(ic->journal_xor[pl_index].page);
> + dst = kmap_local_page(target_pl[pl_index].page);
> +
> + memcpy(dst + pl_offset, src0 + pl_offset, this_step);
> + crypto_xor(dst + pl_offset, src1 + pl_offset, this_step);
> +
> + kunmap_local(dst);
> + kunmap_local(src1);
> + kunmap_local(src0);
> +
> + /* mirror async_tx per-page completion accounting */
> + complete_journal_op(comp);
>
> pl_index++;
> pl_offset = 0;
> @@ -947,8 +951,6 @@ static void xor_journal(struct dm_integrity_c *ic, bool
> encrypt, unsigned int se
> } while (n_bytes);
>
> BUG_ON(n_sections);
> -
> - async_tx_issue_pending_all();
> }
>
> static void complete_journal_encrypt(void *data, int err)
>
> --
> 2.43.0
>
