zram: use zcomp compressing backends

Do not perform direct LZO compress/decompress calls, initialise
and use zcomp LZO backend (single compression stream) instead.

[akpm@linux-foundation.org: resolve conflicts with zram-delete-zram_init_device-fix.patch]
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 36 insertions, 43 deletions

diff --git a/drivers/block/zram/Makefile b/drivers/block/zram/Makefile
index cb0f9ced6a93..757c6a5cadff 100644
--- a/drivers/block/zram/Makefile
+++ b/drivers/block/zram/Makefile
@@ -1,3 +1,3 @@
-zram-y  :=      zram_drv.o
+zram-y  :=      zcomp_lzo.o zcomp.o zram_drv.o
 
 obj-$(CONFIG_ZRAM)      +=      zram.o
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 76ba67673a90..98823f9ca8b1 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -29,7 +29,6 @@
 #include <linux/genhd.h>
 #include <linux/highmem.h>
 #include <linux/slab.h>
-#include <linux/lzo.h>
 #include <linux/string.h>
 #include <linux/vmalloc.h>
 
@@ -38,6 +37,7 @@
 /* Globals */
 static int zram_major;
 static struct zram *zram_devices;
+static const char *default_compressor = "lzo";
 
 /* Module params (documentation at end) */
 static unsigned int num_devices = 1;
@@ -160,8 +160,6 @@ static inline int valid_io_request(struct zram *zram, struct bio *bio)
 static void zram_meta_free(struct zram_meta *meta)
 {
         zs_destroy_pool(meta->mem_pool);
-        kfree(meta->compress_workmem);
-        free_pages((unsigned long)meta->compress_buffer, 1);
         vfree(meta->table);
         kfree(meta);
 }
@@ -173,22 +171,11 @@ static struct zram_meta *zram_meta_alloc(u64 disksize)
         if (!meta)
                 goto out;
 
-        meta->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
-        if (!meta->compress_workmem)
-                goto free_meta;
-
-        meta->compress_buffer =
-                (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
-        if (!meta->compress_buffer) {
-                pr_err("Error allocating compressor buffer space\n");
-                goto free_workmem;
-        }
-
         num_pages = disksize >> PAGE_SHIFT;
         meta->table = vzalloc(num_pages * sizeof(*meta->table));
         if (!meta->table) {
                 pr_err("Error allocating zram address table\n");
-                goto free_buffer;
+                goto free_meta;
         }
 
         meta->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM);
@@ -198,15 +185,10 @@ static struct zram_meta *zram_meta_alloc(u64 disksize)
         }
 
         rwlock_init(&meta->tb_lock);
-        mutex_init(&meta->buffer_lock);
         return meta;
 
 free_table:
         vfree(meta->table);
-free_buffer:
-        free_pages((unsigned long)meta->compress_buffer, 1);
-free_workmem:
-        kfree(meta->compress_workmem);
 free_meta:
         kfree(meta);
         meta = NULL;
@@ -280,8 +262,7 @@ static void zram_free_page(struct zram *zram, size_t index)
 
 static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
 {
-        int ret = LZO_E_OK;
-        size_t clen = PAGE_SIZE;
+        int ret = 0;
         unsigned char *cmem;
         struct zram_meta *meta = zram->meta;
         unsigned long handle;
@@ -301,12 +282,12 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
         if (size == PAGE_SIZE)
                 copy_page(mem, cmem);
         else
-                ret = lzo1x_decompress_safe(cmem, size, mem, &clen);
+                ret = zcomp_decompress(zram->comp, cmem, size, mem);
         zs_unmap_object(meta->mem_pool, handle);
         read_unlock(&meta->tb_lock);
 
         /* Should NEVER happen. Return bio error if it does. */
-        if (unlikely(ret != LZO_E_OK)) {
+        if (unlikely(ret)) {
                 pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
                 atomic64_inc(&zram->stats.failed_reads);
                 return ret;
@@ -349,7 +330,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 
         ret = zram_decompress_page(zram, uncmem, index);
         /* Should NEVER happen. Return bio error if it does. */
-        if (unlikely(ret != LZO_E_OK))
+        if (unlikely(ret))
                 goto out_cleanup;
 
         if (is_partial_io(bvec))
@@ -374,11 +355,10 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
         struct page *page;
         unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
         struct zram_meta *meta = zram->meta;
+        struct zcomp_strm *zstrm;
         bool locked = false;
 
         page = bvec->bv_page;
-        src = meta->compress_buffer;
-
         if (is_partial_io(bvec)) {
                 /*
                  * This is a partial IO. We need to read the full page
@@ -394,7 +374,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
                         goto out;
         }
 
-        mutex_lock(&meta->buffer_lock);
+        zstrm = zcomp_strm_find(zram->comp);
         locked = true;
         user_mem = kmap_atomic(page);
 
@@ -420,22 +400,20 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
                 goto out;
         }
 
-        ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen,
-                               meta->compress_workmem);
+        ret = zcomp_compress(zram->comp, zstrm, uncmem, &clen);
         if (!is_partial_io(bvec)) {
                 kunmap_atomic(user_mem);
                 user_mem = NULL;
                 uncmem = NULL;
         }
 
-        if (unlikely(ret != LZO_E_OK)) {
+        if (unlikely(ret)) {
                 pr_err("Compression failed! err=%d\n", ret);
                 goto out;
         }
-
+        src = zstrm->buffer;
         if (unlikely(clen > max_zpage_size)) {
                 clen = PAGE_SIZE;
-                src = NULL;
                 if (is_partial_io(bvec))
                         src = uncmem;
         }
@@ -457,6 +435,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
                 memcpy(cmem, src, clen);
         }
 
+        zcomp_strm_release(zram->comp, zstrm);
+        locked = false;
         zs_unmap_object(meta->mem_pool, handle);
 
         /*
@@ -475,10 +455,9 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
         atomic64_inc(&zram->stats.pages_stored);
 out:
         if (locked)
-                mutex_unlock(&meta->buffer_lock);
+                zcomp_strm_release(zram->comp, zstrm);
         if (is_partial_io(bvec))
                 kfree(uncmem);
-
         if (ret)
                 atomic64_inc(&zram->stats.failed_writes);
         return ret;
@@ -522,6 +501,7 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
                 zs_free(meta->mem_pool, handle);
         }
 
+        zcomp_destroy(zram->comp);
         zram_meta_free(zram->meta);
         zram->meta = NULL;
         /* Reset stats */
@@ -539,6 +519,7 @@ static ssize_t disksize_store(struct device *dev,
         u64 disksize;
         struct zram_meta *meta;
         struct zram *zram = dev_to_zram(dev);
+        int err;
 
         disksize = memparse(buf, NULL);
         if (!disksize)
@@ -551,10 +532,17 @@ static ssize_t disksize_store(struct device *dev,
 
         down_write(&zram->init_lock);
         if (init_done(zram)) {
-                zram_meta_free(meta);
-                up_write(&zram->init_lock);
                 pr_info("Cannot change disksize for initialized device\n");
-                return -EBUSY;
+                err = -EBUSY;
+                goto out_free_meta;
+        }
+
+        zram->comp = zcomp_create(default_compressor);
+        if (!zram->comp) {
+                pr_info("Cannot initialise %s compressing backend\n",
+                                default_compressor);
+                err = -EINVAL;
+                goto out_free_meta;
         }
 
         zram->meta = meta;
@@ -563,6 +551,11 @@ static ssize_t disksize_store(struct device *dev,
         up_write(&zram->init_lock);
 
         return len;
+
+out_free_meta:
+        up_write(&zram->init_lock);
+        zram_meta_free(meta);
+        return err;
 }
 
 static ssize_t reset_store(struct device *dev,
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 1d5b1f5786a8..45e04f7b713f 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -16,9 +16,10 @@
 #define _ZRAM_DRV_H_
 
 #include <linux/spinlock.h>
-#include <linux/mutex.h>
 #include <linux/zsmalloc.h>
 
+#include "zcomp.h"
+
 /*
  * Some arbitrary value. This is just to catch
  * invalid value for num_devices module parameter.
@@ -81,17 +82,16 @@ struct zram_stats {
 
 struct zram_meta {
         rwlock_t tb_lock;       /* protect table */
-        void *compress_workmem;
-        void *compress_buffer;
         struct table *table;
         struct zs_pool *mem_pool;
-        struct mutex buffer_lock; /* protect compress buffers */
 };
 
 struct zram {
         struct zram_meta *meta;
         struct request_queue *queue;
         struct gendisk *disk;
+        struct zcomp *comp;
+
         /* Prevent concurrent execution of device init, reset and R/W request */
         struct rw_semaphore init_lock;
         /*