[PATCH v2] null_blk: Fix the description of the cache_size module argument

[Genjian <zhanggenjian@xxxxxxx>]

From: Genjian Zhang <zhanggenjian@xxxxxxxxxx>

When executing modinfo null_blk, there is an error in the description
of module parameter mbps, and the output information of cache_size is
incomplete.The output of modinfo before and after applying this patch
is as follows:

Before:
[...]
parm:           cache_size:ulong
[...]
parm:           mbps:Cache size in MiB for memory-backed device.
		Default: 0 (none) (uint)
[...]

After:
[...]
parm:           cache_size:Cache size in MiB for memory-backed device.
		Default: 0 (none) (ulong)
[...]
parm:           mbps:Limit maximum bandwidth (in MiB/s).
		Default: 0 (no limit) (uint)
[...]

Fixes: 058efe000b31 ("null_blk: add module parameters for 4 options")
Signed-off-by: Genjian Zhang <zhanggenjian@xxxxxxxxxx>
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
---
 drivers/block/null_blk/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 91642c9a3b29..f982027e8c85 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -223,7 +223,7 @@ MODULE_PARM_DESC(discard, "Support discard operations (requires memory-backed nu
 
 static unsigned long g_cache_size;
 module_param_named(cache_size, g_cache_size, ulong, 0444);
-MODULE_PARM_DESC(mbps, "Cache size in MiB for memory-backed device. Default: 0 (none)");
+MODULE_PARM_DESC(cache_size, "Cache size in MiB for memory-backed device. Default: 0 (none)");
 
 static bool g_fua = true;
 module_param_named(fua, g_fua, bool, 0444);
-- 
2.25.1