Re: [patch] [SCSI] target: return -ENOMEM instead of -1 in target_core_rd.c

Nicholas A. Bellinger
2011-01-26T22:42:07Z

On Wed, 2011-01-26 at 11:51 +0300, Dan Carpenter wrote:
> -1 is -EPERM but -ENOMEM is more appropriate for allocation errors.
>
> Signed-off-by: Dan Carpenter <error27@gmail.com>
>

Hi Dan,

> diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
> index 979aebf..e7fc512 100644
> --- a/drivers/target/target_core_rd.c
> +++ b/drivers/target/target_core_rd.c
> @@ -161,7 +161,7 @@ static int rd_build_device_space(struct rd_dev *rd_dev)
> if (!(sg_table)) {
> printk(KERN_ERR "Unable to allocate memory for Ramdisk"
> " scatterlist tables\n");
> - return -1;
> + return -ENOMEM;
> }
>
> rd_dev->sg_table_array = sg_table;
> @@ -176,7 +176,7 @@ static int rd_build_device_space(struct rd_dev *rd_dev)
> if (!(sg)) {
> printk(KERN_ERR "Unable to allocate scatterlist array"
> " for struct rd_dev\n");
> - return -1;
> + return -ENOMEM;
> }
>
> sg_init_table((struct scatterlist *)&sg[0], sg_per_table);
> @@ -192,7 +192,7 @@ static int rd_build_device_space(struct rd_dev *rd_dev)
> if (!(pg)) {
> printk(KERN_ERR "Unable to allocate scatterlist"
> " pages for struct rd_dev_sg_table\n");
> - return -1;
> + return -ENOMEM;
> }
> sg_assign_page(&sg[j], pg);
> sg[j].length = PAGE_SIZE;

Ok, these first three are fine for propigating up the proper errno in
configfs attribute context from within rd_build_device_space() ->
rd_create_virtdevice()

> @@ -780,7 +780,7 @@ static int rd_DIRECT_without_offset(
> se_mem = kmem_cache_zalloc(se_mem_cache, GFP_KERNEL);
> if (!(se_mem)) {
> printk(KERN_ERR "Unable to allocate struct se_mem\n");
> - return -1;
> + return -ENOMEM;
> }
> INIT_LIST_HEAD(&se_mem->se_list);
>

This one is actually within TCM backend struct
se_subsystem_api->do_task() execution context, and should be using the
PYX_TRANSPORT_* failure codes from target_core_transport.h. I think
this needs to be returning PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES or
PYX_TRANSPORT_LU_COMM_FAILURE, which is then converted up to SCSI status
+sense for struct se_cmd in transport_generic_request_failure().

How about the following patch to address rd_build_device_space() with
errno.., and we address the rd_DIRECT_*_offset() allocation failure
cases in a seperate patch..?

Thanks!

--nab

diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
index 0d0a583..663177e 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -151,7 +151,7 @@ static int rd_build_device_space(struct rd_dev *rd_dev)
if (rd_dev->rd_page_count <= 0) {
printk(KERN_ERR "Illegal page count: %u for Ramdisk device\n",
rd_dev->rd_page_count);
- return -1;
+ return -EINVAL;
}
total_sg_needed = rd_dev->rd_page_count;

@@ -161,7 +161,7 @@ static int rd_build_device_space(struct rd_dev *rd_dev)
if (!(sg_table)) {
printk(KERN_ERR "Unable to allocate memory for Ramdisk"
" scatterlist tables\n");
- return -1;
+ return -ENOMEM;
}

rd_dev->sg_table_array = sg_table;
@@ -176,7 +176,7 @@ static int rd_build_device_space(struct rd_dev *rd_dev)
if (!(sg)) {
printk(KERN_ERR "Unable to allocate scatterlist array"
" for struct rd_dev\n");
- return -1;
+ return -ENOMEM;
}

sg_init_table((struct scatterlist *)&sg[0], sg_per_table);
@@ -192,7 +192,7 @@ static int rd_build_device_space(struct rd_dev *rd_dev)
if (!(pg)) {
printk(KERN_ERR "Unable to allocate scatterlist"
" pages for struct rd_dev_sg_table\n");
- return -1;
+ return -ENOMEM;
}
sg_assign_page(&sg[j], pg);
sg[j].length = PAGE_SIZE;
@@ -254,15 +254,14 @@ static struct se_device *rd_create_virtdevice(
struct se_dev_limits dev_limits;
struct rd_dev *rd_dev = p;
struct rd_host *rd_host = hba->hba_ptr;
- int dev_flags = 0, ret = -EINVAL;
+ int dev_flags = 0, ret;
char prod[16], rev[4];

memset(&dev_limits, 0, sizeof(struct se_dev_limits));

- if (rd_build_device_space(rd_dev) < 0) {
- ret = -ENOMEM;
+ ret = rd_build_device_space(rd_dev);
+ if (ret < 0)
goto fail;
- }

snprintf(prod, 16, "RAMDISK-%s", (rd_dev->rd_direct) ? "DR" : "MCP");
snprintf(rev, 4, "%s", (rd_dev->rd_direct) ? RD_DR_VERSION :