The patch titled
Subject: zram: simplify bvec iteration in __zram_make_request
has been added to the -mm mm-unstable branch. Its filename is
zram-simplify-bvec-iteration-in-__zram_make_request.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-simplify-bvec-iteration-in-__zram_make_request.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: zram: simplify bvec iteration in __zram_make_request
Date: Thu, 6 Apr 2023 16:40:49 +0200
bio_for_each_segment synthetize bvecs that never cross page boundaries, so
don't duplicate that work in an inner loop.
Link: https://lkml.kernel.org/r/20230406144102.149231-4-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 42 ++++++++------------------------
1 file changed, 11 insertions(+), 31 deletions(-)
--- a/drivers/block/zram/zram_drv.c~zram-simplify-bvec-iteration-in-__zram_make_request
+++ a/drivers/block/zram/zram_drv.c
@@ -174,12 +174,6 @@ static inline u32 zram_get_priority(stru
return prio & ZRAM_COMP_PRIORITY_MASK;
}
-static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
-{
- *index += (*offset + bvec->bv_len) / PAGE_SIZE;
- *offset = (*offset + bvec->bv_len) % PAGE_SIZE;
-}
-
static inline void update_used_max(struct zram *zram,
const unsigned long pages)
{
@@ -1966,16 +1960,10 @@ static int zram_bvec_rw(struct zram *zra
static void __zram_make_request(struct zram *zram, struct bio *bio)
{
- int offset;
- u32 index;
- struct bio_vec bvec;
struct bvec_iter iter;
+ struct bio_vec bv;
unsigned long start_time;
- index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
- offset = (bio->bi_iter.bi_sector &
- (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
-
switch (bio_op(bio)) {
case REQ_OP_DISCARD:
case REQ_OP_WRITE_ZEROES:
@@ -1986,24 +1974,16 @@ static void __zram_make_request(struct z
}
start_time = bio_start_io_acct(bio);
- bio_for_each_segment(bvec, bio, iter) {
- struct bio_vec bv = bvec;
- unsigned int unwritten = bvec.bv_len;
-
- do {
- bv.bv_len = min_t(unsigned int, PAGE_SIZE - offset,
- unwritten);
- if (zram_bvec_rw(zram, &bv, index, offset,
- bio_op(bio), bio) < 0) {
- bio->bi_status = BLK_STS_IOERR;
- break;
- }
-
- bv.bv_offset += bv.bv_len;
- unwritten -= bv.bv_len;
-
- update_position(&index, &offset, &bv);
- } while (unwritten);
+ bio_for_each_segment(bv, bio, iter) {
+ u32 index = iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
+ u32 offset = (iter.bi_sector & (SECTORS_PER_PAGE - 1)) <<
+ SECTOR_SHIFT;
+
+ if (zram_bvec_rw(zram, &bv, index, offset, bio_op(bio),
+ bio) < 0) {
+ bio->bi_status = BLK_STS_IOERR;
+ break;
+ }
}
bio_end_io_acct(bio, start_time);
bio_endio(bio);
_
Patches currently in -mm which might be from hch@xxxxxx are
zram-remove-valid_io_request.patch
zram-make-zram_bio_discard-more-self-contained.patch
zram-simplify-bvec-iteration-in-__zram_make_request.patch
zram-move-discard-handling-to-zram_submit_bio.patch
zram-return-early-on-error-in-zram_bvec_rw.patch
zram-refactor-highlevel-read-and-write-handling.patch
zram-dont-use-highmem-for-the-bounce-buffer-in-zram_bvec_readwrite.patch
zram-rename-__zram_bvec_read-to-zram_read_page.patch
zram-directly-call-zram_read_page-in-writeback_store.patch
zram-refactor-zram_bdev_read.patch
zram-dont-pass-a-bvec-to-__zram_bvec_write.patch
zram-refactor-zram_bdev_write.patch
zram-pass-a-page-to-read_from_bdev.patch
zram-dont-return-errors-from-read_from_bdev_async.patch
zram-fix-synchronous-reads.patch
zram-return-errors-from-read_from_bdev_sync.patch
