From: Sergey Senozhatsky senozhatsky@chromium.org
mainline inclusion from mainline-v6.2-rc1 commit 5561347aa598b6b12fb6069788ccec9b5e5ebec1 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I7TWVA CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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We will use non-WB variant in ZRAM page recompression path.
Link: https://lkml.kernel.org/r/20221109115047.2921851-4-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky senozhatsky@chromium.org Acked-by: Minchan Kim minchan@kernel.org Cc: Alexey Romanov avromanov@sberdevices.ru Cc: Nhat Pham nphamcs@gmail.com Cc: Nitin Gupta ngupta@vflare.org Cc: Suleiman Souhlal suleiman@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org
Conflicts: drivers/block/zram/zram_drv.c
Signed-off-by: Jinjiang Tu tujinjiang@huawei.com --- drivers/block/zram/zram_drv.c | 69 +++++++++++++++++++++++++---------- 1 file changed, 49 insertions(+), 20 deletions(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 369b24f871ce..4ebd60a1ae37 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1317,8 +1317,29 @@ static void zram_free_page(struct zram *zram, size_t index) ~(1UL << ZRAM_LOCK | 1UL << ZRAM_UNDER_WB)); }
-static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, - struct bio *bio, bool partial_io) +/* + * Reads a page from the writeback devices. Corresponding ZRAM slot + * should be unlocked. + */ +static int zram_bvec_read_from_bdev(struct zram *zram, struct page *page, + u32 index, struct bio *bio, bool partial_io) +{ + struct bio_vec bvec = { + .bv_page = page, + .bv_len = PAGE_SIZE, + .bv_offset = 0, + }; + + return read_from_bdev(zram, &bvec, zram_get_element(zram, index), bio, + partial_io); +} + +/* + * Reads (decompresses if needed) a page from zspool (zsmalloc). + * Corresponding ZRAM slot should be locked. + */ +static int zram_read_from_zspool(struct zram *zram, struct page *page, + u32 index) { struct zcomp_strm *zstrm; unsigned long handle; @@ -1326,20 +1347,6 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, void *src, *dst; int ret;
- zram_slot_lock(zram, index); - if (zram_test_flag(zram, index, ZRAM_WB)) { - struct bio_vec bvec; - - zram_slot_unlock(zram, index); - - bvec.bv_page = page; - bvec.bv_len = PAGE_SIZE; - bvec.bv_offset = 0; - return read_from_bdev(zram, &bvec, - zram_get_element(zram, index), - bio, partial_io); - } - handle = zram_get_handle(zram, index); if (!handle || zram_test_flag(zram, index, ZRAM_SAME)) { unsigned long value; @@ -1349,7 +1356,6 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, mem = kmap_atomic(page); zram_fill_page(mem, PAGE_SIZE, value); kunmap_atomic(mem); - zram_slot_unlock(zram, index); return 0; }
@@ -1371,17 +1377,40 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, zcomp_stream_put(zram->comps[ZRAM_PRIMARY_COMP]); } zs_unmap_object(zram->mem_pool, handle); - zram_slot_unlock(zram, index); + return ret; +} + +static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, + struct bio *bio, bool partial_io) +{ + int ret; + + zram_slot_lock(zram, index); + if (!zram_test_flag(zram, index, ZRAM_WB)) { + /* Slot should be locked through out the function call */ + ret = zram_read_from_zspool(zram, page, index); + zram_slot_unlock(zram, index); + } else { + /* Slot should be unlocked before the function call */ + zram_slot_unlock(zram, index); + + /* A null bio means rw_page was used, we must fallback to bio */ + if (!bio) + return -EOPNOTSUPP; + + ret = zram_bvec_read_from_bdev(zram, page, index, bio, + partial_io); + }
/* Should NEVER happen. Return bio error if it does. */ - if (WARN_ON(ret)) + if (WARN_ON(ret < 0)) pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
return ret; }
static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, - u32 index, int offset, struct bio *bio) + u32 index, int offset, struct bio *bio) { int ret; struct page *page;