[RFC][PATCH 6/9] zram: make stream find and release functions static

From: Sergey Senozhatsky
Date: Mon Sep 21 2015 - 09:15:43 EST


Hide (make static) zstrm find and release function and introduce
zcomp_compress_begin()/zcomp_compress_end(). We will have begin
and end functions around compression (this patch) and decompression
(next patch). So the work flow is evolving to:

zstrm = foo_begin();
foo(zstrm);
foo_end(zstrm);

where foo is compress or decompress zcomp functions.

This patch is a preparation to make crypto API-powered zcomp
possible. The reasoning is that some crypto compression backends
require zstrm for decompression.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
drivers/block/zram/zcomp.c | 27 +++++++++++++++++++++++++--
drivers/block/zram/zcomp.h | 8 ++++++--
drivers/block/zram/zram_drv.c | 6 +++---
3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 5cb13ca..52d5b04 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -296,16 +296,39 @@ bool zcomp_set_max_streams(struct zcomp *comp, int num_strm)
return comp->set_max_streams(comp, num_strm);
}

-struct zcomp_strm *zcomp_strm_find(struct zcomp *comp)
+static struct zcomp_strm *zcomp_strm_find(struct zcomp *comp)
{
return comp->strm_find(comp);
}

-void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm)
+static void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm)
{
comp->strm_release(comp, zstrm);
}

+/* Never return NULL, may sleep */
+struct zcomp_strm *zcomp_compress_begin(struct zcomp *comp)
+{
+ return zcomp_strm_find(comp);
+}
+
+void zcomp_compress_end(struct zcomp *comp, struct zcomp_strm *zstrm)
+{
+ zcomp_strm_release(comp, zstrm);
+}
+
+/* May return NULL, may sleep */
+struct zcomp_strm *zcomp_decompress_begin(struct zcomp *comp)
+{
+ return NULL;
+}
+
+void zcomp_decompress_end(struct zcomp *comp, struct zcomp_strm *zstrm)
+{
+ if (zstrm)
+ zcomp_strm_release(comp, zstrm);
+}
+
int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
const unsigned char *src, size_t *dst_len)
{
diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
index 46e2b9f..616e013 100644
--- a/drivers/block/zram/zcomp.h
+++ b/drivers/block/zram/zcomp.h
@@ -56,12 +56,16 @@ bool zcomp_available_algorithm(const char *comp);
struct zcomp *zcomp_create(const char *comp, int max_strm);
void zcomp_destroy(struct zcomp *comp);

-struct zcomp_strm *zcomp_strm_find(struct zcomp *comp);
-void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm);
+
+struct zcomp_strm *zcomp_compress_begin(struct zcomp *comp);
+void zcomp_compress_end(struct zcomp *comp, struct zcomp_strm *zstrm);

int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
const unsigned char *src, size_t *dst_len);

+struct zcomp_strm *zcomp_decompress_begin(struct zcomp *comp);
+void zcomp_decompress_end(struct zcomp *comp, struct zcomp_strm *zstrm);
+
int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
size_t src_len, unsigned char *dst);

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index c93aeb8..7dda8a5 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -673,7 +673,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
goto out;
}

- zstrm = zcomp_strm_find(zram->comp);
+ zstrm = zcomp_compress_begin(zram->comp);
user_mem = kmap_atomic(page);

if (is_partial_io(bvec)) {
@@ -744,7 +744,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
memcpy(cmem, src, clen);
}

- zcomp_strm_release(zram->comp, zstrm);
+ zcomp_compress_end(zram->comp, zstrm);
zstrm = NULL;
zs_unmap_object(meta->mem_pool, handle);

@@ -764,7 +764,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
atomic64_inc(&zram->stats.pages_stored);
out:
if (zstrm)
- zcomp_strm_release(zram->comp, zstrm);
+ zcomp_compress_end(zram->comp, zstrm);
if (is_partial_io(bvec))
kfree(uncmem);
return ret;
--
2.6.0.rc2.10.gf4d9753

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