On (23/04/03 13:42), Andrew Morton wrote:
[..]
> zram_bvec_read() is called with the bio set to NULL only in
> writeback_store() function. When a writeback is triggered,
> zram_bvec_read() is called only if ZRAM_WB flag is not set. That will
> result only calling zram_read_from_zspool() in __zram_bvec_read().
>
> rw_page callback used to call read_from_bdev_async with a NULL parent bio
> but that has been removed since commit 3222d8c2a7f8 ("block: remove
> ->rw_page").
>
> We can now safely always call bio_chain() as read_from_bdev_async() will
> be called with a parent bio set. A WARN_ON_ONCE is added if this function
> is called with parent set to NULL.
>
> Link: https://lore.kernel.org/linux-mm/ZBHcl8Pz2ULb4RGD@xxxxxxxxxxxxx/ [1]
> Link: https://lore.kernel.org/linux-mm/20230322135013.197076-1-p.raghav@xxxxxxxxxxx/ [2]
> Link: https://lore.kernel.org/linux-mm/8adb0770-6124-e11f-2551-6582db27ed32@xxxxxxxxxxx/ [3]
> Link: https://lkml.kernel.org/r/20230403132221.94921-2-p.raghav@xxxxxxxxxxx
> Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: Christian Brauner <brauner@xxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Jens Axboe <axboe@xxxxxxxxx>
> Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
> Cc: Martin Brandenburg <martin@xxxxxxxxxxxx>
> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Cc: Mike Marshall <hubcap@xxxxxxxxxxxx>
> Cc: Minchan Kim <minchan@xxxxxxxxxx>
> Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Tested-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
