diff options
Diffstat (limited to 'debian/patches-rt/0247-drivers-zram-Don-t-disable-preemption-in-zcomp_strea.patch')
| -rw-r--r-- | debian/patches-rt/0247-drivers-zram-Don-t-disable-preemption-in-zcomp_strea.patch | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/debian/patches-rt/0247-drivers-zram-Don-t-disable-preemption-in-zcomp_strea.patch b/debian/patches-rt/0247-drivers-zram-Don-t-disable-preemption-in-zcomp_strea.patch new file mode 100644 index 000000000..e12dd3c3c --- /dev/null +++ b/debian/patches-rt/0247-drivers-zram-Don-t-disable-preemption-in-zcomp_strea.patch @@ -0,0 +1,107 @@ +From fcbeb7ab5dc2a2e2f1243df805e9a4f0103b212b Mon Sep 17 00:00:00 2001 +From: Mike Galbraith <umgwanakikbuti@gmail.com> +Date: Thu, 20 Oct 2016 11:15:22 +0200 +Subject: [PATCH 247/347] drivers/zram: Don't disable preemption in + zcomp_stream_get/put() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +In v4.7, the driver switched to percpu compression streams, disabling +preemption via get/put_cpu_ptr(). Use a per-zcomp_strm lock here. We +also have to fix an lock order issue in zram_decompress_page() such +that zs_map_object() nests inside of zcomp_stream_put() as it does in +zram_bvec_write(). + +Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> +[bigeasy: get_locked_var() -> per zcomp_strm lock] +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/block/zram/zcomp.c | 12 ++++++++++-- + drivers/block/zram/zcomp.h | 1 + + drivers/block/zram/zram_drv.c | 5 +++-- + 3 files changed, 14 insertions(+), 4 deletions(-) + +diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c +index 4ed0a78fdc09..dd65a27ae2cc 100644 +--- a/drivers/block/zram/zcomp.c ++++ b/drivers/block/zram/zcomp.c +@@ -116,12 +116,19 @@ ssize_t zcomp_available_show(const char *comp, char *buf) + + struct zcomp_strm *zcomp_stream_get(struct zcomp *comp) + { +- return *get_cpu_ptr(comp->stream); ++ struct zcomp_strm *zstrm; ++ ++ zstrm = *this_cpu_ptr(comp->stream); ++ spin_lock(&zstrm->zcomp_lock); ++ return zstrm; + } + + void zcomp_stream_put(struct zcomp *comp) + { +- put_cpu_ptr(comp->stream); ++ struct zcomp_strm *zstrm; ++ ++ zstrm = *this_cpu_ptr(comp->stream); ++ spin_unlock(&zstrm->zcomp_lock); + } + + int zcomp_compress(struct zcomp_strm *zstrm, +@@ -171,6 +178,7 @@ int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node) + pr_err("Can't allocate a compression stream\n"); + return -ENOMEM; + } ++ spin_lock_init(&zstrm->zcomp_lock); + *per_cpu_ptr(comp->stream, cpu) = zstrm; + return 0; + } +diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h +index 41c1002a7d7d..d424eafcbf8e 100644 +--- a/drivers/block/zram/zcomp.h ++++ b/drivers/block/zram/zcomp.h +@@ -14,6 +14,7 @@ struct zcomp_strm { + /* compression/decompression buffer */ + void *buffer; + struct crypto_comp *tfm; ++ spinlock_t zcomp_lock; + }; + + /* dynamic per-device compression frontend */ +diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c +index 04e4297f8318..2919ad13bce9 100644 +--- a/drivers/block/zram/zram_drv.c ++++ b/drivers/block/zram/zram_drv.c +@@ -1028,6 +1028,7 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, + unsigned long handle; + unsigned int size; + void *src, *dst; ++ struct zcomp_strm *zstrm; + + if (zram_wb_enabled(zram)) { + zram_slot_lock(zram, index); +@@ -1062,6 +1063,7 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, + + size = zram_get_obj_size(zram, index); + ++ zstrm = zcomp_stream_get(zram->comp); + src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO); + if (size == PAGE_SIZE) { + dst = kmap_atomic(page); +@@ -1069,14 +1071,13 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, + kunmap_atomic(dst); + ret = 0; + } else { +- struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp); + + dst = kmap_atomic(page); + ret = zcomp_decompress(zstrm, src, size, dst); + kunmap_atomic(dst); +- zcomp_stream_put(zram->comp); + } + zs_unmap_object(zram->mem_pool, handle); ++ zcomp_stream_put(zram->comp); + zram_slot_unlock(zram, index); + + /* Should NEVER happen. Return bio error if it does. */ +-- +2.36.1 + |