mirror of https://github.com/torvalds/linux.git
b0377ee804
slot_free() basically completely resets the slots by clearing all of
its flags and attributes. While zram_writeback_complete() restores
some of flags back (those that are necessary for async read
decompression) we still lose a lot of slot's metadata. For example,
slot's ac-time, or ZRAM_INCOMPRESSIBLE.
More importantly, restoring flags/attrs requires extra attention as
some of the flags are directly affecting zram device stats. And the
original code did not pay that attention. Namely ZRAM_HUGE slots
handling in zram_writeback_complete(). The call to slot_free() would
decrement ->huge_pages, however when zram_writeback_complete() restored
the slot's ZRAM_HUGE flag, it would not get reflected in an incremented
->huge_pages. So when the slot would finally get freed, slot_free()
would decrement ->huge_pages again, leading to underflow.
Fix this by open-coding the required memory free and stats updates in
zram_writeback_complete(), rather than calling the destructive
slot_free(). Since we now preserve the ZRAM_HUGE flag on written-back
slots (for the deferred decompression path), we also update slot_free()
to skip decrementing ->huge_pages if ZRAM_WB is set.
Link: https://lkml.kernel.org/r/20260320023143.2372879-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20260319034912.1894770-1-senozhatsky@chromium.org
Fixes:
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|---|---|---|
| .. | ||
| aoe | ||
| drbd | ||
| mtip32xx | ||
| null_blk | ||
| rnbd | ||
| rnull | ||
| xen-blkback | ||
| zram | ||
| Kconfig | ||
| Makefile | ||
| amiflop.c | ||
| ataflop.c | ||
| brd.c | ||
| floppy.c | ||
| loop.c | ||
| n64cart.c | ||
| nbd.c | ||
| ps3disk.c | ||
| ps3vram.c | ||
| rbd.c | ||
| rbd_types.h | ||
| sunvdc.c | ||
| swim.c | ||
| swim3.c | ||
| swim_asm.S | ||
| ublk_drv.c | ||
| virtio_blk.c | ||
| xen-blkfront.c | ||
| z2ram.c | ||
| zloop.c | ||