The patch titled
Subject: zram: avoid lockdep splat by revalidate_disk
has been removed from the -mm tree. Its filename was
zram-avoid-lockdep-splat-by-revalidate_disk.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Minchan Kim <minchan@xxxxxxxxxx>
Subject: zram: avoid lockdep splat by revalidate_disk
Sasha reported lockdep warning [1] introduced by [2].
It could be fixed by doing disk revalidation out of the init_lock.
It's okay because disk capacity change is protected by init_lock
so that revalidate_disk always sees up-to-date value so there is
no race.
[1] https://lkml.org/lkml/2014/7/3/735
[2] zram: revalidate disk after capacity change
Fixes 2e32baea46ce542c56 ("zram: revalidate disk after capacity change").
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Cc: "Alexander E. Patrakov" <patrakov@xxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Jerome Marchand <jmarchan@xxxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
CC: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)
diff -puN drivers/block/zram/zram_drv.c~zram-avoid-lockdep-splat-by-revalidate_disk drivers/block/zram/zram_drv.c
--- a/drivers/block/zram/zram_drv.c~zram-avoid-lockdep-splat-by-revalidate_disk
+++ a/drivers/block/zram/zram_drv.c
@@ -622,11 +622,18 @@ static void zram_reset_device(struct zra
memset(&zram->stats, 0, sizeof(zram->stats));
zram->disksize = 0;
- if (reset_capacity) {
+ if (reset_capacity)
set_capacity(zram->disk, 0);
- revalidate_disk(zram->disk);
- }
+
up_write(&zram->init_lock);
+
+ /*
+ * Revalidate disk out of the init_lock to avoid lockdep splat.
+ * It's okay because disk's capacity is protected by init_lock
+ * so that revalidate_disk always sees up-to-date capacity.
+ */
+ if (reset_capacity)
+ revalidate_disk(zram->disk);
}
static ssize_t disksize_store(struct device *dev,
@@ -666,8 +673,15 @@ static ssize_t disksize_store(struct dev
zram->comp = comp;
zram->disksize = disksize;
set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
- revalidate_disk(zram->disk);
up_write(&zram->init_lock);
+
+ /*
+ * Revalidate disk out of the init_lock to avoid lockdep splat.
+ * It's okay because disk's capacity is protected by init_lock
+ * so that revalidate_disk always sees up-to-date capacity.
+ */
+ revalidate_disk(zram->disk);
+
return len;
out_destroy_comp:
_
Patches currently in -mm which might be from minchan@xxxxxxxxxx are
origin.patch
dma-cma-separate-core-cma-management-codes-from-dma-apis.patch
dma-cma-support-alignment-constraint-on-cma-region.patch
dma-cma-support-arbitrary-bitmap-granularity.patch
dma-cma-support-arbitrary-bitmap-granularity-fix.patch
cma-generalize-cma-reserved-area-management-functionality.patch
ppc-kvm-cma-use-general-cma-reserved-area-management-framework.patch
mm-cma-clean-up-cma-allocation-error-path.patch
mm-cma-change-cma_declare_contiguous-to-obey-coding-convention.patch
mm-cma-clean-up-log-message.patch
mm-vmscan-remove-remains-of-kswapd-managed-zone-all_unreclaimable.patch
mm-vmscan-rework-compaction-ready-signaling-in-direct-reclaim.patch
mm-vmscan-remove-all_unreclaimable.patch
mm-vmscan-move-swappiness-out-of-scan_control.patch
mm-vmallocc-clean-up-map_vm_area-third-argument.patch
mm-refactor-page-index-offset-getters.patch
mm-refactor-page-index-offset-getters-fix.patch
mm-compactionc-isolate_freepages_block-small-tuneup.patch
zram-rename-struct-table-to-zram_table_entry.patch
zram-remove-unused-sector_size-define.patch
zram-use-size_t-instead-of-u16.patch
zram-remove-global-tb_lock-with-fine-grain-lock.patch
mm-zbud-change-zbud_alloc-size-type-to-size_t.patch
mm-zpool-implement-common-zpool-api-to-zbud-zsmalloc.patch
mm-zpool-zbud-zsmalloc-implement-zpool.patch
mm-zpool-update-zswap-to-use-zpool.patch
debugging-keep-track-of-page-owners.patch
page-owners-correct-page-order-when-to-free-page.patch
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