102 lines
3.3 KiB
Diff
102 lines
3.3 KiB
Diff
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From 61751ce1ba547bd0ef0457be194e8aee3c81d577 Mon Sep 17 00:00:00 2001
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From: Mike Galbraith <umgwanakikbuti@gmail.com>
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Date: Thu, 20 Oct 2016 11:15:22 +0200
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Subject: [PATCH 311/365] drivers/zram: Don't disable preemption in
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zcomp_stream_get/put()
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In v4.7, the driver switched to percpu compression streams, disabling
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preemption via get/put_cpu_ptr(). Use a per-zcomp_strm lock here. We
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also have to fix an lock order issue in zram_decompress_page() such
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that zs_map_object() nests inside of zcomp_stream_put() as it does in
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zram_bvec_write().
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Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
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[bigeasy: get_locked_var() -> per zcomp_strm lock]
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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drivers/block/zram/zcomp.c | 12 ++++++++++--
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drivers/block/zram/zcomp.h | 1 +
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drivers/block/zram/zram_drv.c | 6 +++---
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3 files changed, 14 insertions(+), 5 deletions(-)
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diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
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index 4b5cd3a7b2b6..fa8329ad79fd 100644
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--- a/drivers/block/zram/zcomp.c
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+++ b/drivers/block/zram/zcomp.c
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@@ -118,12 +118,19 @@ ssize_t zcomp_available_show(const char *comp, char *buf)
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struct zcomp_strm *zcomp_stream_get(struct zcomp *comp)
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{
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- return *get_cpu_ptr(comp->stream);
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+ struct zcomp_strm *zstrm;
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+
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+ zstrm = *this_cpu_ptr(comp->stream);
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+ spin_lock(&zstrm->zcomp_lock);
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+ return zstrm;
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}
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void zcomp_stream_put(struct zcomp *comp)
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{
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- put_cpu_ptr(comp->stream);
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+ struct zcomp_strm *zstrm;
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+
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+ zstrm = *this_cpu_ptr(comp->stream);
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+ spin_unlock(&zstrm->zcomp_lock);
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}
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int zcomp_compress(struct zcomp_strm *zstrm,
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@@ -174,6 +181,7 @@ static int __zcomp_cpu_notifier(struct zcomp *comp,
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pr_err("Can't allocate a compression stream\n");
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return NOTIFY_BAD;
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}
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+ spin_lock_init(&zstrm->zcomp_lock);
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*per_cpu_ptr(comp->stream, cpu) = zstrm;
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break;
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case CPU_DEAD:
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diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
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index 478cac2ed465..f7a6efdc3285 100644
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--- a/drivers/block/zram/zcomp.h
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+++ b/drivers/block/zram/zcomp.h
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@@ -14,6 +14,7 @@ struct zcomp_strm {
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/* compression/decompression buffer */
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void *buffer;
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struct crypto_comp *tfm;
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+ spinlock_t zcomp_lock;
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};
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/* dynamic per-device compression frontend */
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diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
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index c864ad57348a..a9765ffa322a 100644
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--- a/drivers/block/zram/zram_drv.c
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+++ b/drivers/block/zram/zram_drv.c
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@@ -577,6 +577,7 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
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struct zram_meta *meta = zram->meta;
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unsigned long handle;
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unsigned int size;
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+ struct zcomp_strm *zstrm;
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zram_lock_table(&meta->table[index]);
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handle = meta->table[index].handle;
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@@ -588,16 +589,15 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
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return 0;
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}
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+ zstrm = zcomp_stream_get(zram->comp);
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cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
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if (size == PAGE_SIZE) {
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memcpy(mem, cmem, PAGE_SIZE);
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} else {
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- struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp);
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-
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ret = zcomp_decompress(zstrm, cmem, size, mem);
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- zcomp_stream_put(zram->comp);
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}
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zs_unmap_object(meta->mem_pool, handle);
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+ zcomp_stream_put(zram->comp);
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zram_unlock_table(&meta->table[index]);
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/* Should NEVER happen. Return bio error if it does. */
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--
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2.28.0
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