Change 130f315a introduced a bug in the handling of incompressible
pages which resulted in memory allocation failure for such pages.
The fix is to store the page as-is i.e. without compression if the
compressed size exceeds a threshold (max_zpage_size) and request
exactly PAGE_SIZE sized buffer from zsmalloc.

Signed-off-by: Nitin Gupta <ngu...@vflare.org>
Reported-by: viech...@gmail.com
Reported-by: paer...@gmail.com
Reported-by: wu.to...@gmail.com
Tested-by: wu.to...@gmail.com
Tested-by: mich...@zugelder.org
---
 drivers/staging/zram/zram_drv.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 653b074..6edefde 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -223,8 +223,13 @@ static int zram_bvec_read(struct zram *zram, struct 
bio_vec *bvec,
        cmem = zs_map_object(zram->mem_pool, zram->table[index].handle,
                                ZS_MM_RO);
 
-       ret = lzo1x_decompress_safe(cmem, zram->table[index].size,
+       if (zram->table[index].size == PAGE_SIZE) {
+               memcpy(uncmem, cmem, PAGE_SIZE);
+               ret = LZO_E_OK;
+       } else {
+               ret = lzo1x_decompress_safe(cmem, zram->table[index].size,
                                    uncmem, &clen);
+       }
 
        if (is_partial_io(bvec)) {
                memcpy(user_mem + bvec->bv_offset, uncmem + offset,
@@ -342,8 +347,11 @@ static int zram_bvec_write(struct zram *zram, struct 
bio_vec *bvec, u32 index,
                goto out;
        }
 
-       if (unlikely(clen > max_zpage_size))
+       if (unlikely(clen > max_zpage_size)) {
                zram_stat_inc(&zram->stats.bad_compress);
+               src = uncmem;
+               clen = PAGE_SIZE;
+       }
 
        handle = zs_malloc(zram->mem_pool, clen);
        if (!handle) {
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to