zram: pass a page to read_from_bdev

read_from_bdev always reads a whole page, so pass a page to it instead of
the bvec and remove the now pointless zram_bvec_read_from_bdev wrapper.

Link: https://lkml.kernel.org/r/20230411171459.567614-15-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 1a7fe75285e6475d350d543c00c982489c4104c8..9a35bb0f1a03dbc1af6428b292f748f280f1421b 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -588,7 +588,7 @@ static void zram_page_end_io(struct bio *bio)
 /*
  * Returns 1 if the submission is successful.
  */
-static int read_from_bdev_async(struct zram *zram, struct bio_vec *bvec,
+static int read_from_bdev_async(struct zram *zram, struct page *page,
                        unsigned long entry, struct bio *parent)
 {
        struct bio *bio;
@@ -599,7 +599,7 @@ static int read_from_bdev_async(struct zram *zram, struct bio_vec *bvec,
                return -ENOMEM;
 
        bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9);
-       if (!bio_add_page(bio, bvec->bv_page, bvec->bv_len, bvec->bv_offset)) {
+       if (!bio_add_page(bio, page, PAGE_SIZE, 0)) {
                bio_put(bio);
                return -EIO;
        }
@@ -795,7 +795,7 @@ struct zram_work {
        struct zram *zram;
        unsigned long entry;
        struct bio *bio;
-       struct bio_vec bvec;
+       struct page *page;
 };
 
 static void zram_sync_read(struct work_struct *work)
@@ -805,7 +805,7 @@ static void zram_sync_read(struct work_struct *work)
        unsigned long entry = zw->entry;
        struct bio *bio = zw->bio;
 
-       read_from_bdev_async(zram, &zw->bvec, entry, bio);
+       read_from_bdev_async(zram, zw->page, entry, bio);
 }
 
 /*
@@ -813,12 +813,12 @@ static void zram_sync_read(struct work_struct *work)
  * chained IO with parent IO in same context, it's a deadlock. To avoid that,
  * use a worker thread context.
  */
-static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec,
+static int read_from_bdev_sync(struct zram *zram, struct page *page,
                                unsigned long entry, struct bio *bio)
 {
        struct zram_work work;
 
-       work.bvec = *bvec;
+       work.page = page;
        work.zram = zram;
        work.entry = entry;
        work.bio = bio;
@@ -831,20 +831,20 @@ static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec,
        return 1;
 }
 
-static int read_from_bdev(struct zram *zram, struct bio_vec *bvec,
+static int read_from_bdev(struct zram *zram, struct page *page,
                        unsigned long entry, struct bio *parent, bool sync)
 {
        atomic64_inc(&zram->stats.bd_reads);
        if (sync) {
                if (WARN_ON_ONCE(!IS_ENABLED(ZRAM_PARTIAL_IO)))
                        return -EIO;
-               return read_from_bdev_sync(zram, bvec, entry, parent);
+               return read_from_bdev_sync(zram, page, entry, parent);
        }
-       return read_from_bdev_async(zram, bvec, entry, parent);
+       return read_from_bdev_async(zram, page, entry, parent);
 }
 #else
 static inline void reset_bdev(struct zram *zram) {};
-static int read_from_bdev(struct zram *zram, struct bio_vec *bvec,
+static int read_from_bdev(struct zram *zram, struct page *page,
                        unsigned long entry, struct bio *parent, bool sync)
 {
        return -EIO;
@@ -1328,20 +1328,6 @@ out:
                ~(1UL << ZRAM_LOCK | 1UL << ZRAM_UNDER_WB));
 }
 
-/*
- * 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;
-
-       bvec_set_page(&bvec, page, PAGE_SIZE, 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.
@@ -1402,11 +1388,14 @@ static int zram_read_page(struct zram *zram, struct page *page, u32 index,
                ret = zram_read_from_zspool(zram, page, index);
                zram_slot_unlock(zram, index);
        } else {
-               /* Slot should be unlocked before the function call */
+               /*
+                * The slot should be unlocked before reading from the backing
+                * device.
+                */
                zram_slot_unlock(zram, index);
 
-               ret = zram_bvec_read_from_bdev(zram, page, index, bio,
-                                              partial_io);
+               ret = read_from_bdev(zram, page, zram_get_element(zram, index),
+                                    bio, partial_io);
        }
 
        /* Should NEVER happen. Return bio error if it does. */