Commit af8b04c6 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Andrew Morton
Browse files

zram: simplify bvec iteration in __zram_make_request 

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/20230411171459.567614-5-hch@lst.de


Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarSergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 0120dd6e

drivers/block/zram/zram_drv.c

+11 −31
Original line number Diff line number Diff line
@@ -175,12 +175,6 @@ static inline u32 zram_get_priority(struct zram *zram, u32 index) 
	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)

{
@@ -1960,16 +1954,10 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, 


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:
@@ -1980,24 +1968,16 @@ static void __zram_make_request(struct zram *zram, struct bio *bio) 
	}



	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;

	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;



		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) {

		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_end_io_acct(bio, start_time);

	bio_endio(bio);