2007-10-29 06:32:54

by Vasily Averin

Subject: i2o: CONFIG_DEBUG_SG compilation fixed

i2o crashed when CONFIG_DEBUG_SG is enabled because i2o_block_request structure
includes array of scatterlists that should be initialised

Signed-off-by: Vasily Averin <[email protected]>
--- a/drivers/message/i2o/i2o_block.c
+++ b/drivers/message/i2o/i2o_block.c
@@ -1137,6 +1137,18 @@ static struct i2o_driver i2o_block_driver = {
*
* Returns 0 on success or negative error code on failure.
*/
+
+#ifdef CONFIG_DEBUG_SG
+static void i2o_block_req_ctor(struct kmem_cache *cachep, void *objp) {
+ sg_init_table(((struct i2o_block_request *)(objp))->sg_table,
+ I2O_MAX_PHYS_SEGMENTS);
+}
+
+#define I2O_BLK_CTOR &i2o_block_req_ctor
+#else
+#define I2O_BLK_CTOR NULL
+#endif
+
static int __init i2o_block_init(void)
{
int rc;
@@ -1147,7 +1159,7 @@ static int __init i2o_block_init(void)
/* Allocate request mempool and slab */
size = sizeof(struct i2o_block_request);
i2o_blk_req_pool.slab = kmem_cache_create("i2o_block_req", size, 0,
- SLAB_HWCACHE_ALIGN, NULL);
+ SLAB_HWCACHE_ALIGN, I2O_BLK_CTOR);
if (!i2o_blk_req_pool.slab) {
osm_err("can't init request slab\n");
rc = -ENOMEM;

2007-10-29 09:01:18

by Jens Axboe

Subject: Re: i2o: CONFIG_DEBUG_SG compilation fixed

On Mon, Oct 29 2007, Vasily Averin wrote:
> i2o crashed when CONFIG_DEBUG_SG is enabled because i2o_block_request structure
> includes array of scatterlists that should be initialised
>
> Signed-off-by: Vasily Averin <[email protected]>
> --- a/drivers/message/i2o/i2o_block.c
> +++ b/drivers/message/i2o/i2o_block.c
> @@ -1137,6 +1137,18 @@ static struct i2o_driver i2o_block_driver = {
> *
> * Returns 0 on success or negative error code on failure.
> */
> +
> +#ifdef CONFIG_DEBUG_SG
> +static void i2o_block_req_ctor(struct kmem_cache *cachep, void *objp) {
> + sg_init_table(((struct i2o_block_request *)(objp))->sg_table,
> + I2O_MAX_PHYS_SEGMENTS);
> +}
> +
> +#define I2O_BLK_CTOR &i2o_block_req_ctor
> +#else
> +#define I2O_BLK_CTOR NULL
> +#endif
> +
> static int __init i2o_block_init(void)
> {
> int rc;
> @@ -1147,7 +1159,7 @@ static int __init i2o_block_init(void)
> /* Allocate request mempool and slab */
> size = sizeof(struct i2o_block_request);
> i2o_blk_req_pool.slab = kmem_cache_create("i2o_block_req", size, 0,
> - SLAB_HWCACHE_ALIGN, NULL);
> + SLAB_HWCACHE_ALIGN, I2O_BLK_CTOR);
> if (!i2o_blk_req_pool.slab) {
> osm_err("can't init request slab\n");
> rc = -ENOMEM;

This should already work, since Oct 24. Your i2o_block_request_alloc()
should look like this:

static inline struct i2o_block_request *i2o_block_request_alloc(void)
{
struct i2o_block_request *ireq;

ireq = mempool_alloc(i2o_blk_req_pool.pool, GFP_ATOMIC);
if (!ireq)
return ERR_PTR(-ENOMEM);

INIT_LIST_HEAD(&ireq->queue);
sg_init_table(ireq->sg_table, I2O_MAX_PHYS_SEGMENTS);

return ireq;
}

Note that I also don't like your solution, no need to change this to be
a constructor setup and you definitely should not guard sg_init_table()
with CONFIG_DEBUG_SG. It needs to be done always.

--
Jens Axboe